View Full Version : Finally at the strip, only 11.57@124, opinions please?


Vetal
07-02-2012, 07:51 PM
First of all thanks to all members of this forum who helped me with the info, advises, pics of their projects and inspiration!
After 4 years of building (turbocharging and getting 4L80E in there) my TransAm is in good running state :) Go 200miles to the strip, race, and go back.
Best result, at 13psi, footbraking the car, was:
11.57@124mph
60': 1.88
1/8: 7.51@96mph
This was just old airfield, no glue. I run 12-bolt 3.73, relocating LCA brackets, Billstein shocks, WS6 springs. MT ET Drags 28x11.5 in the rear. 383ci with my own built turbo kit, with TC78. 3500 Circle-D converter.

Since this was basically my first time at the track with new setup I'm asking for opinions. How does it look? Is chassis "working"? I honestly expected better 60ft - I was racing my other car (Nissan 200SX 1.8L) and it got 60ft' of 1.72-1.75 on smaller tire. My best in TransAm was 1.83.
http://www.youtube.com/watch?v=j0WrpJH53lY
http://www.youtube.com/watch?v=lMiNbgyZ23w
Unfortunately these were only 2 clips of my runs...
What can you tell from them?
Thanks! I know this was just first track day and I'll work out "bugs" with time, I think car should run at least 10.9x with TC78 turbo?

B18B1LS1
07-02-2012, 08:11 PM
You have the mph of a 10-second car, but it's way to lazy out of the hole. How much boost is it making off the line? A transbrake and 2-step would work wonders for you.

Vetal
07-02-2012, 08:19 PM
Hmm... Just checked. I had 6-7psi on the footbrake. Do you think I need more boost off the line? I was spinning like crazy already...

B18B1LS1
07-02-2012, 09:18 PM
Ahh ok, didn't think it was spinning, I thought it was bogging. I should have payed closer attention to that first video. Time for some more suspension!

heymoej
07-02-2012, 09:27 PM
first video,sounds like you were hitting the rev limiter.?.?

MillsMotorvation
07-02-2012, 09:38 PM
first video,sounds like you were hitting the rev limiter.?.?

I agree, you over rev, and your gear is most likely to short. You need a 3.55, hell maybe even a 3.08 thats what I run, but leaving at idle 2.20 60ft, my car mph 127. So my vote is suspention, and gear. Nice car!! Oh I run a cheap ebay turbo GT45.

Vetal
07-03-2012, 02:17 AM
Yepp the car was banging off the limiter in 1st and probably 2nd too. Gearchange set at 5500, rev limiter at 6200.
Still, do you think 3.73 gear is soooooo way too much? Hell I'm not leaving at 20 psi :)) I would like to think gear is at least OK, but my 60ft suffer because of smth. else - either suspension or overall slowness when I start off the footbrake.
It looks to me like front end is not rising up much, and on the other hand rear raises a lot when I bring the revs up, is it how it should be?

nocooler
07-03-2012, 10:24 AM
No transfer - so it's not planting the tires.

Vetal
07-03-2012, 11:23 AM
I also left stock tranny tables so it shifted early into 2nd then back to 1st then 2nd then in a moment in 3rd already, also applied TC lock, crazy :bomb:

coolmanvette75
07-03-2012, 11:41 AM
A bit off topic but how much clearancing did you have to do to fit those tires? I have the same exact ones I will be installing on friday. Any pics?

Vetal
07-03-2012, 11:49 AM
A bit off topic but how much clearancing did you have to do to fit those tires? I have the same exact ones I will be installing on friday. Any pics?had to bang the inner fenders quite a bit. Also bend front lips of the rear bumper. And to get wheels perfectly centered in the wells I got my LCA's shortened few millimeters (cut and rewelded back near front bushing housing).
But back to topic :) What's wrong, what to try and what to test? :)

T6Rocket
07-03-2012, 01:58 PM
I also left stock tranny tables so it shifted early into 2nd then back to 1st then 2nd then in a moment in 3rd already, also applied TC lock, crazy :bomb:

Looks like you figured out some of the issue. If you have a 6200 rev limit, dont cut it off at 5500, let it eat!

I also agree with suspension work and 3.08 or other tall gears. That 4L80E has a low first gear.

Al

MillsMotorvation
07-03-2012, 02:18 PM
Ok well you seem to know what you need, Good luck!

chasgiv3
07-03-2012, 03:18 PM
In watching the video I don't see much weight transfer at all to the rear tires. The rear end doesn't hunker down hardly at all and I don't see much lift from the front.

What shocks are you running? What are the settings on them? Are you still running a front sway bar?

Vetal
07-04-2012, 03:46 AM
Looks like you figured out some of the issue. If you have a 6200 rev limit, dont cut it off at 5500, let it eat!

I also agree with suspension work and 3.08 or other tall gears. That 4L80E has a low first gear.

AlWell 5500 is still too high because it still bangs into rev limiter!
Yes, suspension, but what exactly?
Hmm I don't know, I saw people put 4.xx gears in theirs and hook...

Vetal
07-04-2012, 03:49 AM
In watching the video I don't see much weight transfer at all to the rear tires. The rear end doesn't hunker down hardly at all and I don't see much lift from the front.

What shocks are you running? What are the settings on them? Are you still running a front sway bar?yepp, neither do I :(
I'm running Bilstein HD shocks and WS6 springs. Yes for front sway bar.
However I remember when I was N/A and had manual tranny (in 2008 I think), it lifted the nose pretty noticeable on launch, on 26" slicks

Vetal
07-04-2012, 03:59 AM
Few pics of 2008-2009 when it was non-turbo and M6 tranny. The nose was probably a bit lighter then, when it had no turbo or intercooler hanging there in front

chasgiv3
07-04-2012, 08:33 AM
I get much better travel with the front sway bar unlinked and to lesson the front end weight even removed. My front end is really heavy also so every little bit helps.
http://i86.photobucket.com/albums/k101/chasgiv3/DSC_1727.jpg

Vetal
07-04-2012, 08:50 AM
Looks like yours hooks "a little" better :)

heymoej
07-04-2012, 01:01 PM
i cant tell in the vids,do you have lighter rims & skinnies on the front?

how much air do you have in the ET Drags 28x11.5 on those runs?

pull the front sway bar off........

N2RACINGLS1's
07-04-2012, 07:18 PM
Here is my take you changed from 26's to 28's you need to check you pinion angle on the drive shaft. You also need to either remove or at least unhook front sway bar. You also need to get adjustable shocks on the front along with the correct coil over springs for the front. If you cannot get the front end up and the weight of the car on the back tires traction will always be a problem.

I would not adjust shift points I would adjust the rev limiter to at least 6,600 RPM's to take care of the shift extension. Your gear is OK for now! The photos I included are what you need to get your car to do! Well you do not need it that high but you need the front tires with very little weight on them.

Good Luck!

N2

Vetal
07-05-2012, 12:26 PM
Here is my take you changed from 26's to 28's you need to check you pinion angle on the drive shaft. You also need to either remove or at least unhook front sway bar. You also need to get adjustable shocks on the front along with the correct coil over springs for the front. If you cannot get the front end up and the weight of the car on the back tires traction will always be a problem.

I would not adjust shift points I would adjust the rev limiter to at least 6,600 RPM's to take care of the shift extension. Your gear is OK for now! The photos I included are what you need to get your car to do! Well you do not need it that high but you need the front tires with very little weight on them.

Good Luck!

N2So when I went 26 -> 28" slicks, I had to change pinion angle? Could that really affect anything?
Everyone says about front sway bar, seems I have to do that first :)
Yes I've ordered front Strange from Midwest Chassis about 3 weeks ago but they still haven't even ordered them from Strange... Waiting...
Yes I see what you mean about shift points/rev limiter but I think it's pointless setting anything now since revs go up very quickly since I'm spinning a lot

heymoej, on the video I had street wheels. But weight of front wheels doesn't affect traction I guess, it's that front end doesn't want to raise above front wheels...

Vetal
07-05-2012, 08:00 PM
So when I went from 26" slicks to 28", my rear end raise 1", and pinion angle became more negative, but according to this post from Madman it shouldn't affect traction in a negative way...
http://ls1tech.com/forums/4507351-post8.html

heymoej
07-05-2012, 08:02 PM
front end weight is bad for weight transfer......
more weight is harder to transfer, which means you have to have your suspension that much better dialed in.

the lighter the front end the easier the weight transfer is to the rear.......then on launch it is easier to transfer that less weight to the rear end.

1ltcap
07-05-2012, 08:15 PM
it looked to me like you spun the shit outta those tires. couldn't tell if it was just on launch, or when you were trying to load the converter.... but you lost a LOT right there on the line.

Vetal
07-05-2012, 08:57 PM
Yepp exactly spun like crazy, and that's what I'm trying to solve and ask for advises... I know track is very bad, but 28x11.5 at 9-11psi should hook a lot better (and I did hook a lot better few years ago).

I don't know, maybe key is that rear end now sits so much higher relative to the front than it was back then?

Sixspeed02TA
07-06-2012, 12:30 AM
I'm normally just a browser but I'm partial to black TA's so I thought I would offer some advice.

I have not followed your build from the beginning so please excuse the ignorance for the specifics of your setup. I agree that with your trap speed (Mid 120's) you have a mid to high 10 second car. You gain or lose that time in the first 300 ft.

Starting with the obvious:
A poorly prepped track is ..... a poorly prepped track. Traction will be challenging. That being said, plan accordingly.

Launch Consistency:
You now have a turbo car. It will not react the same way a NA, S/C or N2O car does off the line. As you know, you canít drive up to the line stab the gas and go. You must learn how to effectively stage, spool and launch the car without upsetting the rear end or burning up the transmission. In the first clip you were actually spinning the tires before you ever released the brakes. In the second clip you blew the tires off in the first 3 feet. Once the tires break loose, the torque generated by your setup is going to spin the tires to the moon, irrelevant of your shift point, rev limit, or rear gear ratio. A 4L80 has so much rotational mass that getting the tires to hook back up is challenging. At a minimum for you to be consistent with your launch technique, you need a two step rev limiter. It is much easier to dial in your launch RPM and build boost if all you have to do is stand on the brake and mash the gas.

Gears?
Your final gear ratio is not your immediate problem. In fact, I run 3.73 gears with a 4L80E and stock shocks / springs with consistent 1.4X 60í times (3700lb race weight). Note: a 4L80E actually has a taller first gear (2.48) than a 4L60E (3.06). The lower rear gearing isnít such a bad thing.

Rear Setup
Check your pinion angle. (Yes it matters) MT ET Drags arenít the best but; tire pressure should be 15 - 17 psi. I would recommend MT 275/60 15 DR or a set of Hoosier DR.
Donít listen to anyone who tells you the rear of the car is supposed to ďsquatĒ. On a properly setup drag car, the rear should actually rise a half inch or so when the rear is planted into the track. The front suspension should also raise slightly indicating weight transfer. I assume you have lowered your car, hence the relocating brackets. Those should be adjustable; experiment with different settings. You want the LCAís parallel with the ground or slightly sloped down toward the rear of the car.

If you donít already have one, get a rear anti-roll bar (Not a sway bar). Wolfe and BMR make nice units. The purpose of this bar is to balance the weight of the car on the back tires. To set one up properly, you need to have the car on a set of corner scales with you in the driver seat. Adjust until the weight is evenly distributed between the rear tires. You mentioned in another post you were having problems with your posi-unit slipping. I couldnít tell in the video, but if you had one tire spinning half way down the track that wonít help you at all. If itís not a street car, throw a spool in it and be done.

Boost Controller?
A good boost controller like an AMS-1000 is irreplaceable on the track for tuning the power for the track conditions. Itís super easy to change your launch boost and ramp rate to accommodate a slippery track. All your boost coming in at once can often overload the track even if you manage to hook it out of the hole.

Rev Limit?
I donít know anything about your motor, but if you have a good set of heads with decent lifters and springs, there should be no reason why you canít turn that motor to 6500. Unless you have an exhaust side flow problem (turbo housing or exhaust), your car should be making tons of power in the 6000 rpm range. LET HER EAT!

Iím not trying to fill you with a line of crap or brag about previous accomplishments. Please take my advice at face value. Seat time will help you more than anything else at this point. Your car runs well, is a hell of a lot of fun to drive around, and will smoke the tires for 1/8th mile. Take pride in that for the brief period of time this brings you grins. The speed bug never quits and you will always want to go faster.
Peace

Vetal
07-11-2012, 06:49 PM
I didn't reply here cause I wanted to measure all angles before posting more. Finally did it.
Sooo... my torque arm is -2.5* (lower in front) and my LCAs are 6* and 7* (higher in front).
That was with 20-24 psi in slicks (street driving) so at the strip rear might sit 1/2 lower with 10-12 psi in slicks.
Suggestions please? :)

Sixspeed02TA
07-11-2012, 08:04 PM
I didn't reply here cause I wanted to measure all angles before posting more. Finally did it.
Sooo... my torque arm is -2.5* (lower in front) and my LCAs are 6* and 7* (higher in front).
That was with 20-24 psi in slicks (street driving) so at the strip rear might sit 1/2 lower with 10-12 psi in slicks.
Suggestions please? :)

Vetal,

The torque arm value you provided isn't especially useful. The Pinion Angle referenced is the angular difference between the pinion shaft inside the rear axle and your drive shaft.


Read this thread for how to properly measure pinion angle:
http://ls1tech.com/forums/suspension-brakes/974198-measuring-pinion-angle.html

The reason this value is important: As torque is applied to the axle it has a natural tendency to rotate the pinion up. For drag strip applications we typically set the pinion angle at ~ (-2.0deg) so under acceleration the drive shaft and pinion gear inside the rear axle are a straight line. However, for normal driving, this may introduce a very small amount of drive-line vibration.

I wouldn't expect dropping your tire pressure is going to have a very dramatic effect on that measurement.

Your lower control arms slope down toward the rear axle. :thumb: You never want them to slope up. That's why lowered cars usually have to run relocation brackets.

10 psi pressure in bias ply slicks can be a handful at 120 mph. Get some radials! They hook just as good.


If you don't have at least a 2 step rev limiter it will very difficult for you to get consistent launches. If you don't know what a 2 step is:

The factory computer is a 1 step rev limit....it kicks in at what ever you program it to (ie 6200) no matter what.
A 2 step gives you another rpm setpoint to limit rpms to....for your application it would be activated by your brake lights. So as long as you have your foot on the brake the motor is limited to what every you program it to (ie 2800). This lets you stand on the brake, press the gas to the floor and not instantly take off. As soon as you release the brake that rpm limit goes away. This lets you dial in your launch rpm and to some extent your launch boost. You will always have that 2 step rpm set low enough that it's impossible to spin the tires prior to releasing the brake. (Which is something I saw you do in your video.)

Go back to the track and get some more videos for us. Racing is the fun part.

Vetal
07-11-2012, 08:14 PM
Sixspeed02TA, thanks for that valuable post!
Launch Consistency:
You now have a turbo car. It will not react the same way a NA, S/C or N2O car does off the line. As you know, you canít drive up to the line stab the gas and go. You must learn how to effectively stage, spool and launch the car without upsetting the rear end or burning up the transmission. In the first clip you were actually spinning the tires before you ever released the brakes. In the second clip you blew the tires off in the first 3 feet. Once the tires break loose, the torque generated by your setup is going to spin the tires to the moon, irrelevant of your shift point, rev limit, or rear gear ratio. A 4L80 has so much rotational mass that getting the tires to hook back up is challenging. At a minimum for you to be consistent with your launch technique, you need a two step rev limiter. It is much easier to dial in your launch RPM and build boost if all you have to do is stand on the brake and mash the gas.I actually was expecting it would be much easier to launch since I went to A4. It probably is, but I'm clearly doing smth. wrong :)
P.S. Didn't notice I was spinning standing at the tree already :)
Gears?
Your final gear ratio is not your immediate problem. In fact, I run 3.73 gears with a 4L80E and stock shocks / springs with consistent 1.4X 60í times (3700lb race weight). Note: a 4L80E actually has a taller first gear (2.48) than a 4L60E (3.06). The lower rear gearing isnít such a bad thing.Yepp I also didn't think this gear is SOOO too short, I think many are running even shorter gears with tons of power

Rear Setup
Check your pinion angle. (Yes it matters) MT ET Drags arenít the best but; tire pressure should be 15 - 17 psi. I would recommend MT 275/60 15 DR or a set of Hoosier DR.It's between -2* and -2.5* depending on tire pressure. Obviously it increased when my rear end raised at the tree...
Donít listen to anyone who tells you the rear of the car is supposed to ďsquatĒ. On a properly setup drag car, the rear should actually rise a half inch or so when the rear is planted into the track. The front suspension should also raise slightly indicating weight transfer. I assume you have lowered your car, hence the relocating brackets. Those should be adjustable; experiment with different settings. You want the LCAís parallel with the ground or slightly sloped down toward the rear of the car.Yepp I learned from here solid axle doesn't have to squat. BUT my squatting much less powerful Nissan gets better 60ft LOL. I don't know whether this what you see in video is "tires planted" or the opposite, car trying to rotate over front wheels, reducing weight on rear tires...

If you donít already have one, get a rear anti-roll bar (Not a sway bar). Wolfe and BMR make nice units. The purpose of this bar is to balance the weight of the car on the back tires. To set one up properly, you need to have the car on a set of corner scales with you in the driver seat. Adjust until the weight is evenly distributed between the rear tires. You mentioned in another post you were having problems with your posi-unit slipping. I couldnít tell in the video, but if you had one tire spinning half way down the track that wonít help you at all. If itís not a street car, throw a spool in it and be done.hmm, I don't know what it is, must read then :) Although shipping to here is sooo expensive that it prohibits from ordering big heavy hardware. I didn't feel problems with spool this time - perhaps I didn't give it enough power before? :/

Boost Controller?
A good boost controller like an AMS-1000 is irreplaceable on the track for tuning the power for the track conditions. Itís super easy to change your launch boost and ramp rate to accommodate a slippery track. All your boost coming in at once can often overload the track even if you manage to hook it out of the hole.yepp controlling boost off the line might help, but can't afford 1000$ EBC...

Rev Limit?
I donít know anything about your motor, but if you have a good set of heads with decent lifters and springs, there should be no reason why you canít turn that motor to 6500. Unless you have an exhaust side flow problem (turbo housing or exhaust), your car should be making tons of power in the 6000 rpm range. LET HER EAT!Nothing too fancy - Patriot Stage2 heads, mild cam. TC78 might be limiting though (might be not, at least not at this power level)
Iím not trying to fill you with a line of crap or brag about previous accomplishments. Please take my advice at face value. Seat time will help you more than anything else at this point. Your car runs well, is a hell of a lot of fun to drive around, and will smoke the tires for 1/8th mile. Take pride in that for the brief period of time this brings you grins. The speed bug never quits and you will always want to go faster.
PeaceI very much agree with you - it was long way, enormous amount of money (and work) for me, it's loud and brutal and fun, but I want it to FLY :) Maybe not 9.x but at least mid-10's.
Problem with seat time is huge - we just don't get many races here. Perhaps 7-10 a year, most of them are on the old dead asphalt (basically - small stone chips). Hell I need AWD :)

Vetal
07-11-2012, 08:27 PM
Vetal,

The torque arm value you provided isn't especially useful. The Pinion Angle referenced is the angular difference between the pinion shaft inside the rear axle and your drive shaft.

Read this thread for how to properly measure pinion angle:
http://http://ls1tech.com/forums/suspension-brakes/974198-measuring-pinion-angle.html
TA angle = rear end = pinion angle. I actually like Madman's way of dealing with pinion angles. Angle between pinion (=rear end) and ground = pinion angle; angle between pinion and driveshaft is driveline angle; only pinion-to-ground angle affects launch traction...

I wouldn't expect dropping your tire pressure is going to have a very dramatic effect on that measurement.Well, 1" less sidewall is same as going from 28" back to 26" at the same pressure... About 0.6* if I remember correctly for 1 inch of change in rear height

Your lower control arms slope down toward the rear axle. :thumb: You never want them to slope up. That's why lowered cars usually have to run relocation brackets.Yepp they slope down toward rear, but 6-7 degrees...

10 psi pressure in bias ply slicks can be a handful at 120 mph. Get some radials! They hook just as good.I don't know, no drama actually... Yes I sail a bit but nothing that feels dangerous

If you don't have at least a 2 step rev limiter it will very difficult for you to get consistent launches. Yes I know, I think it even can be set up in HPTuners. But, it's not that hard to set RPMs with foot actually. At least not after Nissan which you rev in neutral at the tree :)

Go back to the track and get some more videos for us. Racing is the fun part.I was at my local track which is nightmare actually... 7.82 @ 98mph :) spin spin spin
here's one low-quality vid:
http://www.youtube.com/watch?v=6oTqv4uE5K4

Sixspeed02TA
07-11-2012, 08:56 PM
Sorry...fixed the link in my other post. Retard Error :drool:

LOL Well, it sounds like your having fun anyway. We are lucky enough to have numerous fantastic tracks thru ought the states. We tend to forget that.

Your car makes a lot of power early. If the track conditions are as slippery as you describe, you'll have to make a conscious effort not to hit it as hard off the line.

I believe MSD makes a 2 and 3 step for LS1 computers:
http://www.thunderracing.com/shop-by/vehicle/1998-2002-LS1-F-Body/Ignition-and-Electronics/Rev-Limiters/
Something to think about.

The rear anti-roll bar I was referencing:
http://www.bmrsuspension.com/?page=products&productid=299

Stripping all excess weight out of cars can help some, but I figure your pretty nose heavy with your Turbo. Yes.....you need to build an AWD Turbo TA. That would solve your problem.:burn:

heymoej
07-11-2012, 09:06 PM
I was at my local track which is nightmare actually... 7.82 @ 98mph :) spin spin spin
here's one low-quality vid:
http://www.youtube.com/watch?v=6oTqv4uE5K4[/QUOTE]


just for reference because of your mph......^^^^^^
my old 98 z28 a4 pt4000 373 gears on 26" et street tire dynoed 407rwhp....

it ran....
1.48 60'
7.00 1/8 @ 100mph
11.08 1/4 @ 121mph

good luck!

Vetal
07-12-2012, 03:39 AM
I was at my local track which is nightmare actually... 7.82 @ 98mph :) spin spin spin
....

just for reference because of your mph......^^^^^^
my old 98 z28 a4 pt4000 373 gears on 26" et street tire dynoed 407rwhp....

it ran....
1.48 60'
7.00 1/8 @ 100mph
11.08 1/4 @ 121mph

good luck!Damn! I was hoping I have more like 550whp, not 400, since your mph are similar :)

Vetal
07-12-2012, 03:56 AM
Just to let you know how bad our only track (this, where last video is from) is, couple of pics...

http://www.bmwpower.lv/files/member_galleries/34/3976/500/1208725638_29209.jpg
http://content20-foto.inbox.lv/albums/v/vetal/Mail-Attachments/photo.sized.jpg

Vetal
07-17-2012, 08:38 PM
Guys what do you think from the vids, did I stage my car correctly at all? Is it OK that it raised rear end considerably when I brought the revs up?

Vetal
07-24-2012, 01:03 PM
I've also remembered that my timing was around 11-12 degrees in those runs, at 11-12psi of boost, is that too low? I probably should set it to 17-20 degrees I think?

Roarin_8
07-24-2012, 04:20 PM
Those are small rocks?! :eek2: I'm sure those get very slippery.

I personally wouldn't race there especially at the trap speeds you are going, things can get nasty pretty quickly.

Vetal
07-24-2012, 07:25 PM
Those are small rocks?! :eek2: I'm sure those get very slippery.

I personally wouldn't race there especially at the trap speeds you are going, things can get nasty pretty quickly.That's the only track in my country (Latvia). Yes this is what is left from what used to be asphalt :( It's here I can only manage 7.9s in 1/8

Roarin_8
07-24-2012, 09:29 PM
oh man, becareful out there.

Vetal
06-13-2013, 11:44 AM
Hey hey, raced last weekend, finally the season started. This time I got 11.1@126mph :) :) Since last year I put lighter hood, front Strange coilovers, some 130lbs of weight in the trunk, and started using transbrake. My best was 11.1@126, with 1.74 60'. But I still feel car should have been much quicker from the line

Vetal
06-13-2013, 01:21 PM
Also I just checked converter slip just before gearchanges. I change gears at 6000rpm, and at this moment converter slip is still about 760-800 rpm. Do I change too early, should I maybe raise change points so it changes at some 6200rpm? I guess converter would catch up with engine rpms much better, but don't know if it would gain speed/ET?