Boost at the line

[hensleyt]

Two years for me ,Best 60 is 1.6 but so inconsistent it was pathetic.I finally installed a 2step and the car is right on the 11.9 ET bracket with a 1.8 60ft,car has more in it but the track wont always hold it.I leave at 2800 @ 12 psi I had to take out -8* of timing on the 2step to keep from blowing the tires off.But my last 6 time slips 11.90-11.97 @112.6-112.4 ,1/8 91.06-91.12 .Need to get my reaction time down to .1s or less and Ill be deadly in the 11.90 class. I spent a lot of time trying to get a good 60ft but finally realized I needed to put the hole race together.Thanks for all the help and good reading

 

[KEVINS]

Almost 5 years since I started this thread, and I have only dropped 2 tenths off mine. Personal best 60' of 1.50. I don't take it to the track often enough to do any suspension tuning. I know I need to work on my instant center, can't find an online calculator for it. Anyone got a link for one?

Here ya go:

http://www.baselinesuspensions.com/instant-center_general.php

ks

 

[Dave_Harris]

.I leave at 2800 @ 12 psi I had to take out -8* of timing on the 2step to keep from blowing the tires off.

I'm working on my 60 as well. While the two step helped greatly, I find that if I immediatly go to WOT on the 2-step and t-brake when I light the 2nd stage light, I barely have enough time to build 6psi before the "go" light. I have a realatively small turbo (GT6162) and a PTC 2800 stall. I have the 2 step set to 2600 rpm. How pray-tell are you building 12 psi in the beams?

I have a stage-wrong brake so I can't bump into the beams, i'm wondering if i need to put a real brake in it.

 

[Kurt04]

I'm working on my 60 as well. While the two step helped greatly, I find that if I immediatly go to WOT on the 2-step and t-brake when I light the 2nd stage light, I barely have enough time to build 6psi before the "go" light. I have a realatively small turbo (GT6162) and a PTC 2800 stall. I have the 2 step set to 2600 rpm. How pray-tell are you building 12 psi in the beams?

I have a stage-wrong brake so I can't bump into the beams, i'm wondering if i need to put a real brake in it.

Have you tried foot braking to build some boost and then bump in? You'll probably want to stage first and hope that the other guy doesn't take too long and burn you down or come in to quick when you aren't ready.

You may need your 2-step higher. Is 6 psi all it will build at that RPM?

 

[Dave_Harris]

Have you tried foot braking to build some boost and then bump in? You'll probably want to stage first and hope that the other guy doesn't take too long and burn you down or come in to quick when you aren't ready.

You may need your 2-step higher. Is 6 psi all it will build at that RPM?

Brakes wont hold any boost. I have seen 9 lbs at that RPM. The difference between 6psi and 9 psi is the difference between a 1.51 and a 1.70 60 ft time.

When I'm the slower car, and leave first, I can be pretty consistant by going WOT when my opponent lights his second stage light, but when I'm the faster car, I end up buiding more boost, lowering my 60' and really have to race the stripe on the big end.

I have really thought about going to a boost controller that uses CO2 reference so I can have it set at 6-7psi while on the brake, then increase the controller to 24psi after launch. That would require an extrernal waste gate though.

The simple method would be to figure out how to get this thing to spool up as much as it will for a given rpm in the timeframe allotted, and just let er rip. I'm thinking a little more stall....

 

[hensleyt]

Are you putting retard it the 2step? I have to It help me to build boost faster
I turn the first light on first if I can,It seems to make the other lane a pick it up.some times.as soon as he is lit the top light I start building a little boost, not WOT about 2000 RPM .
If I'm lucky they will light the bottom.I go WOT and ease of the brake just a little and slide in the second light,I have a ball bearing 5857 that spools fast and 235 front tires that help hold the car
Your right the other lane will never cooperate with a turbo car if they can make it hard,being consistent is ruff the last two months the track prep wouldn't hold a 5 PSI leave

 

[Kurt04]

Are you putting retard it the 2step? I have to It help me to build boost faster
I turn the first light on first if I can,It seems to make the other lane a pick it up.some times.as soon as he is lit the top light I start building a little boost, not WOT about 2000 RPM .
If I'm lucky they will light the bottom.I go WOT and ease of the brake just a little and slide in the second light,I have a ball bearing 5857 that spools fast and 235 front tires that help hold the car
Your right the other lane will never cooperate with a turbo car if they can make it hard,being consistent is ruff the last two months the track prep wouldn't hold a 5 PSI leave

That was my next question.

 

[hensleyt]

I just installed a PL two weeks ago,I'm looking at it with a new though because of this,
PL shows @WOT 2800 =11lb boost @3.8 TPS 2700 6 lb boost @3.0TPS 2600 4.7 lb boost
My rpm to boost dose not look that much better than yours, from 6psi -11 is .562 sec. I just ease in to it never stab it

 

[Dave_Harris]

Yes, I'm pulling timing via 2 step. I'm going to run some tests this weekend to see what spools better, retarded timing vs advanced timing and rich vs lean. I'm also curious to see if setting the 2 step rpm to the stall speed of the converter changes anything. I just want to max out boost for a given RPM on the 2 step, and be able to reach that boost level in 3 secs or so.....

 

[Dave_Harris]

Started a new thread on this here -

http://turbobuick.com/forums/threads/spool-time.382301/#post-3069067

 

[DoubleD]

1.460-1.480 consistent on a nicely prepped track
Tires: MT DR 275/60R15 18psi maybe 3-5 second burnout starting in second, shifting to 3rd then off the line lock when it hits 5000 rpm (100 ish mph). Weld alumastar wheels (15x8), MT sportsman skinny fronts
Front: QA1-R single adjustable on zero, tubular cheapy arms (gbody), taller upper and lower ball joints, all very well lubricated. Moog 5658 springs.
Rear: Rod end DA uppers, hr bushings on axle. UMI roto joint DA lowers. 3rd or 4th gen rear springs (WS6 i believe) non-variable rate. Once again well lubricated. Hellwig body mounted (pro-touring) bar on medium setting, pinion angle around -2 to -3
Brakes: Newly rebuilt stock brakes with ceramic pads... nothing fancy. Vacuum brake conversion.
Motor: TE60, 3250-3500 stall neal chance welded converter, TH400, roller cam 210-215
Technique: stomp the daylights out of the brakes. push down even harder as you start to build boost since your assist is going away... The car creeps a little bit at around 10 psi, I try to leave around 12. rpms are probably around 3600, but I don't look at them. did not have a working 2 step yet, so I will tweak that later. Get off the brakes FAST when you wanna go and put the skinny one to the wood as fast as you can. Can't go WOT on the foot brake...

thats sorta it. I keep scaring myself and shifting too soon, but that is after the 60' mark. It lifts the left front about 2-3 inches off the ground.

I think the car has more left even off the foot brake. we'll see next year.

Hopefully this helps someone! I'll admit, I like talking about my successes... I'm willing to help out where I can!

-DD

 

[Black Air]

1.460-1.480 consistent on a nicely prepped track
Tires: MT DR 275/60R15 18psi maybe 3-5 second burnout starting in second, shifting to 3rd then off the line lock when it hits 5000 rpm (100 ish mph). Weld alumastar wheels (15x8), MT sportsman skinny fronts
Front: QA1-R single adjustable on zero, tubular cheapy arms (gbody), taller upper and lower ball joints, all very well lubricated. Moog 5658 springs.
Rear: Rod end DA uppers, hr bushings on axle. UMI roto joint DA lowers. 3rd or 4th gen rear springs (WS6 i believe) non-variable rate. Once again well lubricated. Hellwig body mounted (pro-touring) bar on medium setting, pinion angle around -2 to -3
Brakes: Newly rebuilt stock brakes with ceramic pads... nothing fancy. Vacuum brake conversion.
Motor: TE60, 3250-3500 stall neal chance welded converter, TH400, roller cam 210-215
Technique: stomp the daylights out of the brakes. push down even harder as you start to build boost since your assist is going away... The car creeps a little bit at around 10 psi, I try to leave around 12. rpms are probably around 3600, but I don't look at them. did not have a working 2 step yet, so I will tweak that later. Get off the brakes FAST when you wanna go and put the skinny one to the wood as fast as you can. Can't go WOT on the foot brake...

thats sorta it. I keep scaring myself and shifting too soon, but that is after the 60' mark. It lifts the left front about 2-3 inches off the ground.

I think the car has more left even off the foot brake. we'll see next year.

Hopefully this helps someone! I'll admit, I like talking about my successes... I'm willing to help out where I can!

-DD

I'm aiming to run hi 10s with my car and any info would be appreciate. It has a 122 plus mph at the big end but I'm running the 200r with mods and art Carr 9" converter with the stock 10 bolt rear with 3.73 gears. I do have Metco lowers and adjustable uppers and I'm able to get my instant center around 100 %. So traction won't be an issue.

 

[huntsg]

Well I'm a rookie at this and trying to learn. I went to Reynolds GA this past November for my first shot at a 1/4 mile track. There was a lot going on at the line and I am sure that with a little practice I could improve and I know a better tune will get me a faster ET. The track hooked really well that weekend since at my local 1/8th track I've had traction problems in the past. I was using a foot brake to build about 5 psi of boost at the line. I probably could have built more, but it's a daily driver with a stock rear end and I didn't want to break anything. I used the same technique DoubleD used, but didn't build as much. My best 60' was 1.647 sec. I've got the upgraded larger ceramic brake pads and wheel cylinders. I've removed the front sway bar and added the bigger ATR sway bar to the rear. There is one air bag on the passenger side with about 9 psi in it and the MT drag radials were at 17-18 psi that day.

 

[DoubleD]

Black Air - Your combo certainly sounds strong in the MPH department. Mine went 99.9 mph to the 1/8 mile and 122 in the quarter and in the high 10s on all my passes, though I am using 3.42 gears. that was at 21-211 psi and 18.5 degrees of timing in a cammed iron head motor though. I think you have all the nice parts to get the job done, but I didn't see what shocks you are running? the QA1s really made a difference as far as weight transfer goes... I definitely recommend the R series on the fronts. I have a standard lakewood 50/50 in the rears of mine that have been on there for a long time.

Huntsg: It sounds like you are also on the right track for your setup, especially being new to the track! Keep in mind I was dinking around on the line waiting for the boost to be just right, so my R/T was pure crap, but when you are getting started, who cares. it isn't a money race. If I need to run one of those I just get up there and give it whatever boost it'll make before the green and drive it. usually in the 1.65 range at 5 lbs of boost, so we are on the same level I'd say. I just recently went to moser c-clips and a girdle cover on my rear end. gives you a little bit better sense of security, though I still drive the car 50 miles to the track. mmm 6262 billet. lemme get that for a few hits wink wink.

I really feel like the body mounted swaybars are a huge help to these cars, not that the ATR is a bad thing though. the front sway bar is removed on my car as well. You also generally don't need the airbags with them, so that allows the car to weight transfer very consistently. I'm going to try some duralast stock replacement non variable rate rear springs next season... I heard they transfer well and I think they will work well too. Also, take out the pinion snubbers. The fbody springs are nice since they are a smaller diameter. makes clearing the exhaust a lot easier!

damn, my brain is all over the place. sorry for the tough read.

-DD

 

[DoubleD]

I have decent powerlogger data from the passes if anyone is bored and wants to look at stuff...

 

[huntsg]

Thanks for the advice. I will say that going to the track is very addicting. My set up includes the eibach springs and bilstein shocks. Why do you say to remove the pinion snubber? I replaced my stock one with a newer bigger one. I will say that when I looked at the stock one it didn't appear to have been used much. I've also been considering beefing up the rear end. Maybe a girdle or control arms...

 

[DoubleD]

My car had an extended one on it, and I'd get decent weight transfer until it hit that thing (I think), then it would unload the tires. This was a little ways down the "track", and then it would lose traction. if you have a decent set of springs that aren't bottoming out the suspension, you don't need the snubber IMO. I also haul all my tools to the track and the car is pretty low, so I don't think you would have a problem without it. I'm no expert, but I think this has been covered previously.

I'd recommend getting control arms for sure. The less wheel hop you have, the better traction you have and the less likely you are to break axles, gears, and carriers due to shock loading. I have a set of boxed stock lower control arms with poly joints in them if you want em. I prefer a more flexible joint that allows the rear to pivot and not bind, thus letting the sway bar do it's job and still letting the rear end move freely. I like my roto joint arms. They act like a rod end but aren't super harsh on the street. they don't deform a lot either, so you can effectively set the pinion angle without a lot of variance.

 

[highboostgn]

1.8@5lbs first time

 

[DoubleD]

got any more description of what happened? did it spin right out of the box or did it spin 10 feet out? did it start rolling the tires on the footbrake? vacuum assist needs a lot of leg pressure to hold a lot of boost in my experience. Suspension modifications?

one thing I see is the extended pinion snubber. I'd use that as a paperweight. My opinion of course.

 

[highboostgn]

got any more description of what happened? did it spin right out of the box or did it spin 10 feet out? did it start rolling the tires on the footbrake? vacuum assist needs a lot of leg pressure to hold a lot of boost in my experience. Suspension modifications?

one thing I see is the extended pinion snubber. I'd use that as a paperweight. My opinion of course.

Spun and track was underwater 4 hours prior to opening