E-diff 2wd quicker 1/4 mile????? [Archive] - Cherokee SRT8 Forum

: E-diff 2wd quicker 1/4 mile?????


cobrakid
05-08-2007, 09:57 PM
...can't sleep...was thinking....

wondering if I put the e-diff fuse on a switch.....

launched the truck in AWD and after it left and shifted into 2nd, flicked switch.

would the 1/4 mile inprove with less drag etc..etc..?

It wouldn't be worth doing unless it would give you a solid tenth.

any thoughts?

Also was wondering, if I did a small e-diff heat the rear tires up slightly burnout....
.....and then left it in AWD with the back tires stickier than the fronts, what
would happen?

....also, for arguments sake, say you had a slick even on just the back, and
it more or less dead hooked and the truck was in AWD and a hard launch...
What would happen?????

Would the front burn harder, like a rear that slips posi, and burns the tire
with the least resistance? interesting?

FastSRT8GC
05-08-2007, 10:03 PM
I am not sure how much the power is used up with the FWD on. Most of the Power is to the rear till there is slippage. If you follow my directions its easy enough to install the switch. Give it a shot and let us know!!

ABeasst
05-08-2007, 10:05 PM
wouldnt putting it on a switch keep it from shifting like when you try and dyno with the fuse pulled and it wont shift out of first.

AT'sGCSRT8
05-08-2007, 10:06 PM
I don't think you should switch from awd to rwd while in motion. I believe it can damage your drivetrain. I remember someone before asking about that. Hmmm let me search around........

FastSRT8GC
05-08-2007, 10:10 PM
I know with my F350 I had to get out of the hole in 4x4 then i would switch out for the driveline loss but that is a true 4x4 system, unlike ours.

cobrakid
05-08-2007, 10:19 PM
...wouldn't want to jeopardize the truck, and tear something up, just
thinking out loud.

thanks....

Street WK
05-08-2007, 10:36 PM
can't sleep? damn gramps :D

HoustonSRT-8
05-08-2007, 10:38 PM
I think using the 2wd mod to heat up the rear tires isn't a bad idea.

googone20
05-08-2007, 11:47 PM
What about just running the whole run in 2wd. TBSS's come in a 2wd version, and many guys pick these because of the less rolling resistance and difference in weight. TonyGXP has gotten his truck to go 12.6-5 on street tires with simple bolt-ons in a 2wd TBSS. I think you may be faster if you learn how to launch it.

tommy25000
05-09-2007, 01:04 AM
I know with my F350 I had to get out of the hole in 4x4 then i would switch out for the driveline loss but that is a true 4x4 system, unlike ours.



same here... i have a fast diesel but i dont think 4wd can truly dis-engage when its udnder load like that? this would seem ussless...?

HoustonSRT-8
05-09-2007, 09:14 AM
TBSS's come in a 2wd version, and many guys pick these because of the less rolling resistance and difference in weight.

Because the AWD systems in those models are removed, not just turned off.

jlandbl
05-09-2007, 10:55 AM
What about just running the whole run in 2wd. TBSS's come in a 2wd version, and many guys pick these because of the less rolling resistance and difference in weight. TonyGXP has gotten his truck to go 12.6-5 on street tires with simple bolt-ons in a 2wd TBSS. I think you may be faster if you learn how to launch it.

Thought his times were on slicks?

GotStroke?
05-09-2007, 11:41 AM
Thought his times were on slicks?

DRs I believe.

9900rpm
05-09-2007, 11:55 AM
If you do a burnout in 2WD, then make the pass on AWD, you would have to shut the truck off after the burnout, flip the switch back to AWD, restart the truck, then roll one full revolution of the wheel for the AWD to kick back in. Simply turning the switch back on will not engage AWD again. Truck has to power cycle AND move. It can be done though.

Launching in full 2WD would suck. It would blaze the sh!t out of the right rear tire and leave behind an expensive trail of rubber and smoke. Being that the GCSRT8 doesn't have a rear LSD. Leaving traction control on, in 2WD wouldn't be good either, as the traction control (the electronic brake slip control thing) would cut timing and brake on the wheel that's spining.

Drag radials on the back, in 2WD, MIGHT work. If you do it, let me know.

BuilderBill
05-09-2007, 12:38 PM
If you do a burnout in 2WD, then make the pass on AWD, you would have to shut the truck off after the burnout, flip the switch back to AWD, restart the truck, then roll one full revolution of the wheel for the AWD to kick back in. Simply turning the switch back on will not engage AWD again. Truck has to power cycle AND move. It can be done though.

Launching in full 2WD would suck. It would blaze the sh!t out of the right rear tire and leave behind an expensive trail of rubber and smoke. Being that the GCSRT8 doesn't have a rear LSD. Leaving traction control on, in 2WD wouldn't be good either, as the traction control (the electronic brake slip control thing) would cut timing and brake on the wheel that's spining.

Drag radials on the back, in 2WD, MIGHT work. If you do it, let me know.
I'm thinking the best launch would be with a 9" Ford and DR on the rear, and leave the JGC in AWD. This way the front would help slightly. I also think I will be doing rear wheel burnouts next time (hopefully with the 9" Ford or equivalent).
Bill

FastSRT8GC
05-09-2007, 12:53 PM
I'm thinking the best launch would be with a 9" Ford and DR on the rear, and leave the JGC in AWD. This way the front would help slightly. I also think I will be doing rear wheel burnouts next time (hopefully with the 9" Ford or equivalent).
Bill


Are you telling us your switching your rear end?

Did the LSD search for the DANA not pan out???

awdrocks
05-09-2007, 01:26 PM
Very interesting subject going on here. I have wanted to try the same with my X. I also wondered about doing the 2wd spin out and then launching in 4x4. Or doing only 2wd.

I have a little different system then the STR8, which I think was only offered in the 2002's and 2003, then they went AWD.

I don't have traction control. But a system called "Control Trac four-wheel-drive". It's not your typical traction control that brakes your tires when slip occurs. It just transfers the power from front to rear, and is capable of transferring 100% of the torque to the front tires, it just goes and never brakes.

I'm essentially in 2wd mode in normal driving conditions, if I get on the gas, the computer knows my intentions and automatically transfers torque to the front before the wheels even begin to spin. Its always in Auto 4X4. I can also go High 4x4 which locks my front and rear diffs, and a Low 4x4 button.

I did whats called a "brown wire" mod. Through a relay and toggle switch I can now go 100% 2wd. It disconnects a simple silonoid that activates the transfer case. The beauty is that I got the tow package that came standard with 3.73 diffs and a rear LSD. I can light up the two rear tires up like a hot rod.

So considerings all the options I have. I will test them all to see what gets the better ET's. Ill try Auto 4x4, High 4x4 and 2wd. I will need slicks on all four corners in High 4x4, I can light up all four 295's now in 4x4 locked mode. But till now the Auto 4x4 works incredible. I should also be able to launch in Auto 4x4 and switch to 2wd after about the 60' mark. Or I can try just some really light wheels and tires with Auto 4x4, or going skinnies up front with slicks... I don't know, I get a headache thinking what will ultimately be the best for the strip, I just need to get out there and try all the combos and stick to the quickest one.

But on the street my Auto 4x4 is a street killer.

I think you guys would do very good by putting a rear LSD as Bill mentioned. You are really limited without it.

awdrocks
05-09-2007, 01:38 PM
Or maybe you can just swap your rear pumpkin with a LSD diff without having to convert to a 9'' Ford?

BuilderBill
05-09-2007, 01:50 PM
Are you telling us your switching your rear end?

Did the LSD search for the DANA not pan out???
Ok, here is the plan:
No available LSD for at least 6 months for us...we all know that means a year.
Working with DTS in Michigan, they recommend a Dana 60 vs. the 9" Ford for us due to the very low pinion in the 9" and an available LSD that maxes out at 550 hp. That won't cut it!So, the plan is a custom DANA 60 with a very streetable LSD good to 950 hp. Ship DTS my spare housing that should arrive any day for them to make us a jig (I will pay the $ 500 jig fee). The brackets would then be cut off my spare and welded onto the new assy. Perfect....wait screwed again!
He thinks the SRT ABS sensors are very non-standard made to work with our small axles vs. the large STRANGE axles. He has come up with a way with STRANGE engineering on the Camero's, which are also basta*dized ABS sensors. Hope to hell it works, it is our only shot as I see it.

The cost should run me approx. $ 3000+. You guys would be at least $ 500 cheaper. If this does work, I would be willing of course to part with my original "1 wheel peel" Dana 44.
Bill

FastSRT8GC
05-09-2007, 01:56 PM
Bill, Lets just weld the crap out of the 44!!!!

awdrocks
05-09-2007, 02:29 PM
Ok, here is the plan:[LIST]
No available LSD for at least 6 months for us...we all know that means a year.
Working with DTS in Michigan, they recommend a Dana 60
Bill

Hey Bill what about a 8.8'' Ford?

BuilderBill
05-09-2007, 03:39 PM
Hey Bill what about a 8.8'' Ford?
AWDrocks,
Interesting setup you have. I'll bet it works better than ours!

A real problem with our rear ends :confused: is the LSD units. If the 9" Ford LSD is only good to a max. of 550 hp then I bet the same is true for the 8.8" Ford also.

It takes a pretty beefy unit to hold up to a supercharged or N2O engine, say maybe 600 awhp.

Wish there was another way, but the Dana 60 should hold up to anything.
GET THE WELDER OUT!:eek:
Bill

awdrocks
05-09-2007, 04:24 PM
AWDrocks,
Interesting setup you have. I'll bet it works better than ours!

A real problem with our rear ends :confused: is the LSD units. If the 9" Ford LSD is only good to a max. of 550 hp then I bet the same is true for the 8.8" Ford also.

It takes a pretty beefy unit to hold up to a supercharged or N2O engine, say maybe 600 awhp.

Wish there was another way, but the Dana 60 should hold up to anything.
GET THE WELDER OUT!:eek:
Bill

Well the 8.8'' is what the Mustangs have, I have it as well in the rear. They can be beefed up to handle gobs of power.

My first goal is 650whp before the N20 and plan on doing it with my stock 8.8''. 650wp is not as harsh on an awd vehicle as it is with a 2wd. The power is distributed to front and rear. The first thing to usually break on the diff if the case cover. Upgrading the cover is a big plus. My stock diff cover looks a lot beefier than the Mustangs 8.8''.

But yeah im surprised to see that they don't come with a standard rear LSD... well neither does the X though, just came with the Class IV tow package. But still the STR8 is a performance based SUV and would have really benefited from it, maybe the 6.4 will come with it.... Prob not though, manufactures don't love us that much.. lol

BREAK THE WELDER OUT!!!! lol

What front diff do you guys have?

BuilderBill
05-09-2007, 04:49 PM
What front diff do you guys have? The front diff is MORE of a joke than the rear, if that is possible. I have a spare stocker though. I agree that a transfer case would most likely let loose 1st. If I blow up the front diff, I will "pull the plug" on the transfer case and therefore run on the rear DR. only. i am sure not going to spend another $ 3000 on the front diff (hopefully).
Bill

GotStroke?
05-09-2007, 05:19 PM
AWDrocks,
Interesting setup you have. I'll bet it works better than ours!

A real problem with our rear ends :confused: is the LSD units. If the 9" Ford LSD is only good to a max. of 550 hp then I bet the same is true for the 8.8" Ford also.

It takes a pretty beefy unit to hold up to a supercharged or N2O engine, say maybe 600 awhp.

Wish there was another way, but the Dana 60 should hold up to anything.
GET THE WELDER OUT!:eek:
Bill

Who told you that about Ford rears? A properly built 8.8" will take 1000HP all day long, 9", you'll never break it.

BuilderBill
05-09-2007, 05:29 PM
Who told you that about Ford rears? A properly built 8.8" will take 1000HP all day long, 9", you'll never break it.
Interesting...I was surmising that! Looks like I'm busted.http://www.cherokeesrt8.com/forums/images/icons/icon11.gif
As soon as my spare arrives, I will talk to the Mike at DTS about it.
Very poor guess on my part it seems with the 8.8" Ford.
Bill

awdrocks
05-09-2007, 06:46 PM
The front diff is MORE of a joke than the rear, if that is possible. I have a spare stocker though. I agree that a transfer case would most likely let loose 1st. If I blow up the front diff, I will "pull the plug" on the transfer case and therefore run on the rear DR. only. i am sure not going to spend another $ 3000 on the front diff (hopefully).
Bill

I have a Dana Super 40 up front. Don't know if those are any good.

Well im sure you will be surprised to learn that your drivetrain might handle much more power than you think. When I started my build EVERYONE I mean EVERYONE said my transfer case was going to blow up, my tranny or something. Knock on wood but I have been running my car for about year with my stock drive train and its holding up just fine. Even still have the stock torque converter!!! (new 3,000 stall TQ is sitting in my garage).

I have what people consider to be a weak tranny, 5r55w and im not sure about my transfer case. But I have been driving my X how I want when I want and it doesn't glitch. Its the same tranny that comes in the new 05+ Mustangs, so that was GREAT news for me... performance upgrades for these trannys are becoming available.

I think the key is to be smart about how you treat your ride. I would HIGHLY recommend a tranny temp gauge. The number on reason for trannys going out is heat. Usually your torque converter goes and takes the tranny with it. Getting a stronger torque converter should also be on your list. If I see my tranny above 180* im off the gas....There are times when I will just be cruising and my tranny reads 200*.... I would never even know it if it wasn't for my gauge. Race someone at 200+* and that could be death to a tranny. I also have a tranny cooler in my garage.

Your tranny and transfer case are build for some power (well not sure about your tranny, but im sure its decent). I'm sure they will hold up a lot better than one thinks.

My tranny is sealed, and Ford recommends like a 100k oil life. Yeah right. I have 44k miles on my X and have already changed its tranny oil two times. At about 25k I felt my tranny shifting weird and lugging. Changed the oil and it was like new again.

I think manufactures sometimes want you to break down, just go with your gut and remember that you could never do your car bad by over maintenanceing (sp) it.

Once I get my twin screw Whipple on im sending my transfer case to Level Ten and they beef it up. It will be like $1,600 for the upgrade and according to them it will be bullet proof. They will also do my tranny. I have independent rear suspension so I will also upgrade my half shafts and get lighter aluminum drive shafts.

But, I might start following the philosophy "if it isn't broke, don't fix it".

BuilderBill
05-10-2007, 07:05 AM
I think the key is to be smart about how you treat your ride. I would HIGHLY recommend a tranny temp gauge. The number on reason for trannys going out is heat. Usually your torque converter goes and takes the tranny with it. Getting a stronger torque converter should also be on your list. If I see my tranny above 180* im off the gas....There are times when I will just be cruising and my tranny reads 200*.... I would never even know it if it wasn't for my gauge. Race someone at 200+* and that could be death to a tranny. I also have a tranny cooler in my garage. The Transmission temp gauge with a cooler would be a great idea.


Once I get my twin screw Whipple on im sending my transfer case to Level Ten and they beef it up. It will be like $1,600 for the upgrade and according to them it will be bullet proof. They will also do my tranny. I have independent rear suspension so I will also upgrade my half shafts and get lighter aluminum drive shafts.

But, I might start following the philosophy "if it isn't broke, don't fix it". You are as determined as we are not to have any driveline failures.
Bill

cobrakid
05-10-2007, 02:29 PM
...thanks for the info on heating up the rear in 2WD mode, then re-starting
with awd enabled.

My question concerning that method, if the back hooked better from the
heated tires, would it then cause the front to spin more?????????

awdrocks
05-10-2007, 10:04 PM
...thanks for the info on heating up the rear in 2WD mode, then re-starting
with awd enabled.

My question concerning that method, if the back hooked better from the
heated tires, would it then cause the front to spin more?????????

The SRT's awd mode should send power back and forth, depending what side is spinning, it will shift some power in the opposite direction... so if the front "wants" or "does" spin at all, the viscous coupling on the awd transfer case will put most of the power on the back, therefore reducing front wheel spin. BUT since you dont have a rear LSD you might get one front tire's to spin... hmmm

What might work well for your driveline is to put some light wheels and tires (slicks) front and rear. Like some 15x8 wheels with some 275/60-15 Micky ET Street radials and hang on.

BuilderBill
05-10-2007, 10:20 PM
The SRT's awd mode should send power back and forth, depending what side is spinning, it will shift some power in the opposite direction... so if the front "wants" or "does" spin at all, the viscous coupling on the awd transfer case will put most of the power on the back, therefore reducing front wheel spin. BUT since you dont have a rear LSD you might get one front tire's to spin... hmmm

What might work well for your driveline is to put some light wheels and tires (slicks) front and rear. Like some 15x8 wheels with some 275/60-15 Micky ET Street radials and hang on.
AWDrocks,
hmmm is correct. This issue is not an easy one to solve. Every time I believe I've got it I receive a PM (which is a good thing for us).
Thanks for all the PM's guys on the rear axle info!!!! This is one informed group.
Bill

awdrocks
05-10-2007, 10:35 PM
AWDrocks,
hmmm is correct. This issue is not an easy one to solve. Every time I believe I've got it I receive a PM (which is a good thing for us).
Thanks for all the PM's guys on the rear axle info!!!! This is one informed group.
Bill

Yep.. I know... just trying to help with some idears!!!

Your def going in the right direction by starting with installing a nice LSD.

Blown7
05-11-2007, 03:54 AM
DESCRIPTION




The NV146 transfer case provides On-Demand Active Four-Wheel Drive for optimum traction in a wide range of conditions and is used in the Grand Cherokee SRT8 vehicles. The transfer case uses an electronically controlled clutch pack to distribute between 0% and 50% of the available torque to the front axle. The NV146 electronics provide an active system because it can anticipate and prevent slip.

The NV146 single-speed transfer case provides the following benefits:

No shift lever or driver interaction required.
On-demand four-wheel drive provides smooth operation and vehicle stability under all conditions because torque is constantly being transferred.
Even torque distribution provides traction to maintain forward motion under most conditions.
The Brake Traction Control System (BTCS) works in tandem with on-demand four-wheel drive. BTCS provides resistance to any wheel that is slipping to allow additional torque transfer to wheels with traction.
Robust design and improved sealing enhance reliability.

Blown7
05-11-2007, 03:57 AM
OPERATION
Controls for the NV146 transfer case active clutch (torque biasing device) are located in the Final Drive Control Module (FDCM) and communicated on the CAN C bus. The FDCM monitors wheel speeds at the front and rear axles to detect wheel slippage. A complete vehicle dynamics model calculates slip at each tire for given vehicle-operating conditions. The clutch pack in the transfer case is engaged to minimize the speed difference between the front and rear axle, resulting in torque transfer to the axle with higher traction. The electronically controlled wet clutch pack uses an electric motor to actuate a sector plate. The sector plate actuates a clutch lever that applies normal force to the multi-disc wet clutch pack bridging the differential. The clutch discs are alternately splined to the front and rear driveshafts. When normal force is applied to this clutch pack, torque is transferred to equalize speed differences between front and rear axles

cobrakid
05-11-2007, 07:43 AM
....let me re-word this again.....and thanks for the info.

Let's say I have slicks on the back only, and it dead hooks, doesn't spin
at all.......will this cause the front tires to burn????????

....or because there is no rear tire slippage, there would be very minimal
torque.....signals sent to use the front diff?

What sucks, is when I spray at the track, if I hit the nos too early, like
right after I floor the Jeep......the tires burn, and it shifts 2nd almost instantly.

...that blows the run, and I usually end up just letting off.

I love this truck, I just wish we could flip a switch and get some more posi
action from both the front and rear diffs.

It would be great to add one of those trick torque converters and spray it,
and not have the truck spin wildly (ie alternating 4 wheel peels) b/c then
these things would run deep in the 11s.

If I was rich, and a little more crazy, I would have a good friend help figure
out how to weld the rear together, without bad consequenses???????? yeah right!

awdrocks
05-12-2007, 02:45 PM
This is prob old news but I was just at Vons and I saw a Motor Trend (I think) mag that had Hesse's STR600... the article said that he did about 10 pulls to try and beat his 12.2 time and never accomplished it. Makes you think, if he even got close to it, im sure the editor would have said something like "but he came close with a 12.3" or something. Makes me think he could not touch the 12.2 claim. And he blew his torque converter trying it!!! Oh and he can replace it for an upgraded converter for just $1,200.... :eek: What is that a gold plated torque converter!!! It was a March issue....

Anyways what caught my eye was that the torque converter went south... I think this would be a good upgrade for the STR8 even if the high stall issue/computer is still in the works, get a stock stall but a stronger one.

EDIT: He was under so much pressure to beat the claimed 12.2 that he toasted the converter... that's funny. I can picture him all pissed and desperate doing run after run after run and KABOOOOM... And he blames the converter but not his stupidity... lol

9900rpm
05-12-2007, 03:50 PM
Let's say I have slicks on the back only, and it dead hooks, doesn't spin
at all.......will this cause the front tires to burn????????

....or because there is no rear tire slippage, there would be very minimal
torque.....signals sent to use the front diff?

My guess would be that if the rears dead hook, the fronts will spin a tiny bit. Reason being that the transfer case/center diff is viscous coupling (from what I know) and that is limited slip. If te rears dead hook, the power would want to go to the front, but because there is LSD in the middle, even power will be distributed, front and rear. If you were running slicks in the rear, I'd do the 2WD thing anyway. Why send ANY power to the fronts if the rears hook? Powering the fronts is just wasted energy (drag resistance).

Blown7
05-12-2007, 04:31 PM
There isn't a coupling, viscous or otherwise just a clutch pack
http://i25.photobucket.com/albums/c96/Blown7/7a03300b.gif

Blown7
05-12-2007, 04:38 PM
That's the problem or lack thereof that makes the new GC so hard to manipulate, every single thing is controlled by all the computers that forget old school tech you gotta be a computer nerd.


Jeff

cobrakid
05-12-2007, 05:44 PM
...awdrocks.....

I heard over a month ago that the Hennesey turbo Jeep had been an all
time best of 11.96 @115 1 time???????

For about $25k less, I think I can get there by upping my shot to 150?????

anybody try a 125 or 150 shot?

I have the good plugs, and can put a little C16 race gas in it????

awdrocks
05-12-2007, 05:50 PM
...awdrocks.....

I heard over a month ago that the Hennesey turbo Jeep had been an all
time best of 11.96 @115 1 time???????

For about $25k less, I think I can get there by upping my shot to 150?????

anybody try a 125 or 150 shot?

I have the good plugs, and can put a little C16 race gas in it????

Yeah 25k... crazy. I bet the stock internals can hold up to the 6psi hes pushing with a good tune... its all in the tune!!!

awdrocks
05-12-2007, 06:09 PM
Oh yea... 10.3:1 compression is a bit high for boost.

Blown7
05-12-2007, 07:28 PM
Oh yea... 10.3:1 compression is a bit high for boost.

Well I really didn't want ot get into on this post, but what the hay,

Blower engines can have a host of compressions from 14-1 down to 6-1 what really matters is the dynamic compression final ratio
lets look at BDS compression ratio chart

Final Compression Ratio (FCR) = [ (Boost÷14.7) + 1 ] x CRBoost = Maximum blower boost14.7 = psi at sea levelCR = engine compression ratioAltitude plays an important role in determining compression ratios. If the altitude in the area where you normally drive is significantly higher than sea level, then your compression ratios will also vary. To determine the effects of the altitude on a calculated compression ratio, use the following formula: Corrected Compression Ratio = FCR - [ (altitude÷1000) x 0.2 ]BLOWER BOOST
COMP RATIO

2 4 6 8 10 12 14
6.5 7.4 8.3 9.2 10 10.9 11.8 12.7
7 8 8.9 9.9 10.8 11.8 12.7 13.6
7.5 8.5 9.5 10.6 11.6 12.6 13.6 14.6
8 9.1 10.2 11.3 12.4 13.4 14.5 15.6 \
8.5 9.7 10.8 12 13.1 14.3 15.4 16.6
10.5 11.9 13.4 14.8 16.2 17.6 19.1 20.5
11 12.5 14.0 15.5 17.0 18.5 20.0 21.5

= Pump Gas = Good Gas


This is a abbreviated chart that I cut and copied from the BDS website http://www.blowerdriveservice.com/techcharts.php#final but the bottom line is this, in a boosted engine the magic number for pump gas is approximately 12.4-1 before detonation starts. In a N/A engine your dynamic compression should be no more than about 8-1. Again any higher and detonation will commence.

What I see on these boards alot is how folks just brag about their static compression is, failing to take in account what the cam timing is. Which is more accurately described as intake valve closing time in relation to the piston travel on the upstroke.

Lets take JH 600 GC, IF HE WAS running 10.3 to 1 with 6 LBS of boost his final compression unadjusted for cam timing would be approxiamately a 16-1 final compression ratio. He would need at least 112 octaine to even stay away from massive blowtorching of the internals.

Look static compression without cam size and duration doesn't mean squat by itself. (Except to post in signatures) I myself care to build my blower engines with less than 8-1 static compression and boost higher pressures.

Jeff

Blown7
05-12-2007, 07:34 PM
Ah heck on these forums charts never line up correctly just move the 2,4,6 etc over to the right lining up over the column. Place the 2 over the 7.5 to start.

Jeff

9900rpm
05-12-2007, 10:38 PM
Blown7.. I didn't realize that our trucks had the clutch packs and not a viscous unit. Isn't it cheaper for a company to put a viscous coupling in instead of the clutch packs with electronics?

cobrakid.. I think 125hp shot of nitrous will put the GCSRT8 into the 11's on stock motor, stock heads. With some C16 in the tank and new plugs, you should be OK. The stock PCM is pretty rich, and timing isn't real aggressive. If you do it, let me know how you make out.

Derwood98
05-12-2007, 11:52 PM
If we have a Dana 44 rear axle, you can get lots of LSD, ARB air lockers or Eaton E lockers.

http://www.4wheelparts.com/PLT5589T12T237.aspx

I run a detroit locker in my off road Jeep and it works awesome. Takes a little getting used to on the road though. I would put in a ARB or Eaton E locker in the rear of the SRT8.

Blown7
05-13-2007, 06:47 AM
Blown7.. I didn't realize that our trucks had the clutch packs and not a viscous unit. Isn't it cheaper for a company to put a viscous coupling in instead of the clutch packs with electronics?


Well I don't know about cost differences and the reason for DC choices but the cluth pack IMHO lends itself to the torque management part and ESP/traction control to better interface with all the control modules.
Now to say it's the ultimate system by any means is up for debate.

Having used viscous couplings and various other forms of Full time 4 wheel drive since the 1970's I myself think that a viscous coupling will not hold up to extreme horsepower due to it's very design. Yes I have busted my far share in high horsepower off road conditions. And even cracked them in half getting out of a snow covered driveway with a stock mid 1980's Jeep grand Wagoneer rocking fore and aft.

I think the clutch pack responds very well to quick engagement.
I myself am concerned about the silent chain drive as I have replaced many of the chains in the old Borg Warner 1339 Quadra Trac's.
My new build CJ7 does have a old 1339, but over the years I have learned to replace the chain every 50K miles due to stretch, so I plan on doing the same to the new GCSRT8.

Also to those of you dragging the GC I would suggest doing the same.
If the chain breaks it will bust the case in half.

Jeff

Blown7
05-13-2007, 07:01 AM
If we have a Dana 44 rear axle, you can get lots of LSD, ARB air lockers or Eaton E lockers.

http://www.4wheelparts.com/PLT5589T12T237.aspx

I run a detroit locker in my off road Jeep and it works awesome. Takes a little getting used to on the road though. I would put in a ARB or Eaton E locker in the rear of the SRT8.

Well I have yet to get my hands on a gutted 226 RBI Big Dana 44 rear housing in the GC but I think with a little machining (again just my gut feeling) that possibly a Dana 60 locker or LSD center could be made to fit, granted the ring gear size for a 60 is around 9.25" but the ring gear size of the big 44 is 8.9" Width wise I have no idea.

One thing I do know is without seriously modifying the frame and suspension of the GC you gotta stay with the 226 RBI footprint.

Or the pinon shaft in the old school 44 is real small diameter wise and the weakest link. The 226 RBI pinon is Dana 60 size. So modifying a spool for the 226 would be the easiest for a dedicated drag car.

Just thinking while I type.............

Jeff

BuilderBill
05-13-2007, 07:48 AM
Well I have yet to get my hands on a gutted 226 RBI Big Dana 44 rear housing in the GC but I think with a little machining (again just my gut feeling) that possibly a Dana 60 locker or LSD center could be made to fit, granted the ring gear size for a 60 is around 9.25" but the ring gear size of the big 44 is 8.9" Width wise I have no idea.
Jeff,
Hope my spare diff's arrive in Charlotte soon!
We can then disassemble and see what are our options are.
Bill

awdrocks
05-13-2007, 11:27 AM
Hey Jeff,

My X has a Dana Super 60 front diff. What insight and opinion can you give me on this diff for big horsepower?

GotStroke?
05-13-2007, 12:45 PM
If we have a Dana 44 rear axle, you can get lots of LSD, ARB air lockers or Eaton E lockers.

http://www.4wheelparts.com/PLT5589T12T237.aspx

I run a detroit locker in my off road Jeep and it works awesome. Takes a little getting used to on the road though. I would put in a ARB or Eaton E locker in the rear of the SRT8.


Eaton E lockers are junk. One almost put Roxanne Sheppard into a starting line wall.

GotStroke?
05-13-2007, 12:48 PM
Lets take JH 600 GC, IF HE WAS running 10.3 to 1 with 6 LBS of boost his final compression unadjusted for cam timing would be approxiamately a 16-1 final compression ratio. He would need at least 112 octaine to even stay away from massive blowtorching of the internals.

Look static compression without cam size and duration doesn't mean squat by itself. (Except to post in signatures) I myself care to build my blower engines with less than 8-1 static compression and boost higher pressures.

Jeff


You also have to take into account cylinder head/chamber design/shape. For instance Modulars prefer more total/final compression when going boosted. You don't want anything less than 9.2:1 static or she's going to be a dog down low. The highest HP forced induction Modular runs 12.5:1 C/R with 40psi. In back to back testing, Mihovetz threw lower compression slugs in the same motor (in the 9.xx range) and ended up losing 150/250rw.

awdrocks
05-13-2007, 12:52 PM
You also have to take into account cylinder head/chamber design/shape. For instance Modulars prefer more total/final compression when going boosted. You don't want anything less than 9.2:1 static or she's going to be a dog down low. The highest HP forced induction Modular runs 12.5:1 C/R with 40psi. In back to back testing, Mihovetz threw lower compression slugs in the same motor (in the 9.xx range) and ended up losing 150/250rw.

I went with 9.3:1 on my mod motor.

GotStroke?
05-13-2007, 04:53 PM
I went with 9.3:1 on my mod motor.

Sounds like a fun piece. Prior to the Al built 5.4 I had a MP sourced (block) 324 big bore stroker with fox lake ported Navi's. They are both good people to work with.

awdrocks
05-13-2007, 09:33 PM
Sounds like a fun piece. Prior to the Al built 5.4 I had a MP sourced (block) 324 big bore stroker with fox lake ported Navi's. They are both good people to work with.

Definitely the best in the business. I ALMOST went with the 324 when they fist started building them, but there is a big debate about the stroke already being a little long stock, and stroking it just makes things worse on the 4.6, the rod angle. So I went with the 304 big bore. I'm letting some time go by with the current 324's out to see if any problems start to arise.

If all goes well ill prob do a bullit 324 from MP with some twin turbos or a 3.4L Whipple. I have actually already talked to John about also maybe doing a 5.4 and doing a big bore/stroker aluminum block with 32v heads from either Renagade or Fox Lake with a big power adder. 1000+whp easy. I would like a wet sleeve with my next setup.... oooh... ok stop day dreaming. That long block would be like 15k alone.

Did you get to use the 32v 324?

Derwood98
05-13-2007, 09:48 PM
Eaton E lockers are junk. One almost put Roxanne Sheppard into a starting line wall.

Why are they junk? I am assuming it did what it was designed to do and the driver was not used to locked diffs. If the locker failed, it would be open and you would have a one wheel wonder. Not sure what happened, but was it the lockers fault?

GotStroke?
05-14-2007, 01:00 AM
Why are they junk? I am assuming it did what it was designed to do and the driver was not used to locked diffs. If the locker failed, it would be open and you would have a one wheel wonder. Not sure what happened, but was it the lockers fault?


They tend to fail, the above was just one example. I'm not big on Eaton diffs at all personally. I blew an Eaton CF limited slip up in just six launches on slicks. The stock diff took well over 50.

GotStroke?
05-14-2007, 01:09 AM
Definitely the best in the business. I ALMOST went with the 324 when they fist started building them, but there is a big debate about the stroke already being a little long stock, and stroking it just makes things worse on the 4.6, the rod angle. So I went with the 304 big bore. I'm letting some time go by with the current 324's out to see if any problems start to arise.

You want nothing to do with a Modular stroker. A stock stroke motor will allow the piston skirt to barely peak out at BDC, with a stroker crank roughly 1/3 of the slug will hang out the bottom, causing instability and piston scoring after as little as a few thousand miles. Additionally the Kellogg sourced 4340 stroker cranks have 2" radiused Chevy journals (weaker than stock) and are rated by Kellog at 750hp at 7500rpm vs. 1400hp/9500rpm (stock). Side load is also increased, and whatever power gains you get from a few extra CI can easily be made, more safely, with a stock stroke motor spun a little higher.
Ask John about doing a 324, he'll tell you the same;)

If all goes well ill prob do a bullit 324 from MP with some twin turbos or a 3.4L Whipple. I have actually already talked to John about also maybe doing a 5.4 and doing a big bore/stroker aluminum block with 32v heads from either Renagade or Fox Lake with a big power adder. 1000+whp easy. I would like a wet sleeve with my next setup.... oooh... ok stop day dreaming. That long block would be like 15k alone.

To be honest the best foundation for a high hp forced induction Modular is a stock displacement motor with a hone of .030" or less. Obviously the upside to a big bore is the extra bore unshrouds the valves which helps flow. The downside is the minimal amount of meat left between bores can cause ring issues due to flex, and also poor gasket sealing. Ted Schwartz for example, ended up hydralocking his MP N/A big bore when one of his head gaskets failed. These are the reasons Ford's had 304CI big bores running around for over ten years, but will never greenlight them for production.

Did you get to use the 32v 324?

The motor lasted around 20 dyno pulls and 26 miles before it dropped a valve--due to the dumbass engine builder cutting the valves to the wrong length. It had the aforementioned ported big port Navi's paired to a 5" shorty 99/01 Cobra intake, and the largest cams ever fitted to a 4v (.550"/.550" lift, and 248/259@.050). Made peak TQ at 7900rpm, we never found peak HP but it was extrapolated to be at 9000rpm+. Absolutely retarded when you're backing it with a heavy synchronized trans (T56).
Anyway, the 5.4 would mop the floor with it all day long.

Jred22
05-14-2007, 04:00 AM
...can't sleep...was thinking....

wondering if I put the e-diff fuse on a switch.....

launched the truck in AWD and after it left and shifted into 2nd, flicked switch.

would the 1/4 mile inprove with less drag etc..etc..?

It wouldn't be worth doing unless it would give you a solid tenth.

any thoughts?

Also was wondering, if I did a small e-diff heat the rear tires up slightly burnout....
.....and then left it in AWD with the back tires stickier than the fronts, what
would happen?

....also, for arguments sake, say you had a slick even on just the back, and
it more or less dead hooked and the truck was in AWD and a hard launch...
What would happen?????

Would the front burn harder, like a rear that slips posi, and burns the tire
with the least resistance? interesting?
nope.

'

awdrocks
05-14-2007, 11:00 AM
Ask John about doing a 324, he'll tell you the same;)
Yep that is exactly why I did not go with the 324. I called John for the first time asking for a 324, and he said "stay faaar away". ;) Same with Johnny Langton. But you are right... the piston just dips to far. I could not be happier with my big bore.

To be honest the best foundation for a high hp forced induction Modular is a stock displacement motor with a hone of .030" or less. Obviously the upside to a big bore is the extra bore unshrouds the valves which helps flow. The downside is the minimal amount of meat left between bores can cause ring issues due to flex, and also poor gasket sealing.

Absolutely agree with you. Stock bore will have the biggest meat between the cylinders therefore handling more power. John built my BB with intension's to run 20psi... Im only at about 6-7psi now, does this big bore no justice. When the 2.3l Whipple goes in at 20psi it will seriously wake up my BB. But yes your right, once I build my new motor if I decide to go over 20psi I will go with a stock bore.


These are the reasons Ford's had 304CI big bores running around for over ten years, but will never greenlight them for production.
Wasn't the cammer a production motor?

The motor lasted around 20 dyno pulls and 26 miles before it dropped a valve--
Ouch

GotStroke?
05-14-2007, 11:52 AM
Wasn't the cammer a production motor?

No, the cammer is strictly FRPP/aftermarket.


FWIW, I just found out today that VT (stroker kings) is under new ownership.

Black07
05-14-2007, 04:04 PM
Whats a SS mini van, oops, I mean trailblazer guy doing on this site?

awdrocks
05-14-2007, 05:00 PM
Whats a SS mini van, oops, I mean trailblazer guy doing on this site?

hehe...

Mini van? By you calling an SS a mini van you might as well look in the mirror. But I don't have an SS... I have an Explorer or code named "X" that even Saleen would only dream of building.

Why am I here? Because its a public forum and we share common drive lines.

BuilderBill
05-14-2007, 10:01 PM
hehe...

Mini van? By you calling an SS a mini van you might as well look in the mirror. But I don't have an SS... I have an Explorer or code named "X" that even Saleen would only dream of building.

Why am I here? Because its a public forum and we share common drive lines.
AWDrocks....you have been most helpful. I certainly look forward to your posts.
Bill

awdrocks
05-14-2007, 10:30 PM
AWDrocks....you have been most helpful. I certainly look forward to your posts.
Bill

Thank you Bill. Ditto.

I enjoy this forum. And my hats off to the these awesome STR8's. Next to none. I wish Ford would got off their ass.

I gotta get back to the garage.... changing my TC oil. I thought it would be toast but it was actually REALLY clean. Still, theres nothing like preventive maintenance. ;)

AT'sGCSRT8
05-14-2007, 10:32 PM
Whats a SS mini van, oops, I mean trailblazer guy doing on this site?

I don't see why he can't post here. All of his posts have been very informitive, and if you would have taken the time to actually read through one of his posts you might have noticed his sig, instead of trying to "stir the pot" so to speak. Anyone who brings useful info is always welcome here, no matter what they drive.

awdrocks
05-14-2007, 10:41 PM
I don't see why he can't post here. All of his posts have been very informitive, and if you would have taken the time to actually read through one of his posts you might have noticed his sig, instead of trying to "stir the pot" so to speak. Anyone who brings useful info is always welcome here, no matter what they drive.

Thank you.

GotStroke?
05-15-2007, 12:12 AM
Leave the Ford guys alone ;)