low 12's

[Shimy87]

Can low 12's be run on street tires? Yes I hear it already, get sticky tires. I plan on it next spring but there is one track day left this year and I wondered if this has been done by many?

[Steve Wood]

Not with your combo

[PacecarTA]

yes ..but good luck youll need the stocker running well to get there
with federal supersteel radials (245/50-16) i managed a 1.80 60' 12.20s
 stock turbo , duttneck, alky, THdown pipe,2800 converter (locking at line)
 i had that tuned in at 24psi pulling 109-110 in the 1/4 and would run right at 12.0s on mickeys with a  1.60 60'

[phil_long]

so much for my dreams.  so a low 12 second car on street tires is about what, a mid 11 sec run on slicks?

[Steve Wood]

Not sure how you came to the conclusion that that is the end of your dreams.

Put a TE44/TA49/5831 turbo on the car plus alky injection and it should run lower 12s ASSUMING the engine and drivetrain are in decent condition and you learn how to drive the car.

He is running a stock turbo and is a bit short on top end power on the top end to make up for hsi traction problems altho his should dip into the 12s with just a little tuning and learning how to manage the throttle at launch.

You guys all think this is something that you just buy a few parts and your problem is solved!  Kenne=Bell would have loved you guys!!!!!!!!!!!!!!!!!!  two tenths here, three tenths there,...

Hardly anyone runs slicks on street cars anymore.  They buy drag radials which seem to work better with less tuning effort which suits the parts buyers that don't want to learn how to tune and drive.

[Shimy87]

Been working on the tuning part of the problem. Have read the Vortex site tuning part over and over. I agree with what your saying Steve, i dont want to buy any more parts for this car, its a driver, not a race car. But I would like it to see its potential in this state. Do you think my lack of top end is tuning ( 792 is rich) or because the stock turbo is all in at 24 LBS.? I do want to get some Nitto's next spring but thats it for parts.
 
On the driving/launching part. Thats hard because you get limited runs at the track I can get to and what hooks there blows away on the street so its tough to practice.
 
No complaints, its all fun, as always I just want to pick the brains of you guys who have been there, done that. Prevents wasting time and energy ( and $$$) in a pointless direction.
 
Thanks!

[PacecarTA]

the more power you have the more youll loose on street tires ,  at lower power of stock its still possible to get some hook , with more power it gets harder to get street tires to move the car without spinning them

 for me on my 87 (x) back when i ran the stock turbo was  stock 87 engine with valvesprings,timing chain,50s, 2800 10.5"LU protorque.   footbraking it would only allow 2100-2400 rpm launches(in vacuum) and let it roll out  on radial street tires  vs 3100 (3-5 psi) and drop the hammer and flash it to 4200 (20 psi before moving 1 foot) with drag radials

 im going to share an old time slip from my 86gn   back in  sept 2007
back then it was more of a street  car  pump gas (with alky) tagged and legal to drive, still is today but it has a th400 trans/xfi/roller cam  and runs 9s...


back then it was closer to a stock car
 bRF 200-4r non lock with stageright brake  , stock block crank rods pistons  etc , ported stock irons with studs ,stock intake ,72lb injectors(mod ecm TTchp) , directscan , 71gtq turbo, cas V2 FMIC, atr double pump,  206 flat tappet cam , atr 3" downpipe (external) with msbc-1 boost control  through mufflers (2.75" duals), hr sway bar ,stock boxed lowers stock uppers , stock front with eibach springs, 3 way adj shocks , 33splines and spool  3500lbs

car had run 10.41 126.99 (1.43 60)  (12/06) on 275/60-15 drag radial with a ttchip

i had it dialed that week to 10.70 126 for brackets . the track had a cruise night /car show that allowed 1 free pass  (no track prep) and most cars were street cars running 14 seconds . so i decided to take it out on the street tires  (245/50-16 gtas) 
 traction was hard to nail and had to launch at 2000rpm  use the ramp stages on the electronic boost controller to walk it out  .

and heres a slip  a week or so later at cecil on drag radials with tune turned up a little more

 

[Steve Wood]

Been working on the tuning part of the problem. Have read the Vortex site tuning part over and over. I agree with what your saying Steve, i dont want to buy any more parts for this car, its a driver, not a race car. But I would like it to see its potential in this state. Do you think my lack of top end is tuning ( 792 is rich) or because the stock turbo is all in at 24 LBS.? I do want to get some Nitto's next spring but thats it for parts.
 
On the driving/launching part. Thats hard because you get limited runs at the track I can get to and what hooks there blows away on the street so its tough to practice.
 
No complaints, its all fun, as always I just want to pick the brains of you guys who have been there, done that. Prevents wasting time and energy ( and $$$) in a pointless direction.
 
Thanks!

The stock turbo gets quite inefficient a bit past 20 psi.  Alky helps cool the charge back down, but it does not make up for the low charge density created by the turbo getting out of its best efficiency range.  Remember that it is not how much boost you are reading, it is all about how many air molecules that get stuffed into the cylinder and that is a function of density.

A larger turbo like the 44/49/5831 don't really do much for you below about 18 psi (on a near stock set up) but they start coming into their own about that point with regard to efficiency and cooler charge output which results in a higher density which is very noticeable in the mid 20's.

Given that they work best with a converter that can be stalled to around 2600-2800 rpm against the foot brake producing about 6-7 psi of boost, they can be very formidable on the street with traction...Usi ng a stock converter that stalls around 2100 or so, they work pretty well with street tires because the big power comes on after it gets rolling.

And, as I have said prior, one can always soften up the power in first and second with the chip if need be.  On the street, going from a roll, it does not make too much difference unless you are going from a very slow speed.

For the average street car, I think it is best to leave the alky suggested settings alone and remove fuel from the chip in most cases.  You do appear rich on top end.  Without a data log, I am not sure on the rest but experience tells me the defaults in the chip are probably going to be rich in first and second but you have to be careful because leaner makes more power and thus more wheel spin.

Like life, tuning is often a juggling act.

[Shimy87]

Got a chance to do some tuning today. Ive got overall WOT fueling set down to 123 (128 default number) and lowest sm reading was 797. Im thinking for a street safe 770 reading I'll end up set around 119. Seems pretty lean but it is what it is. It sure is pulling good as I work on this. I know every car is different but that being said is that a pretty lean setting relative to most? Im not getting any kr so alls well, just wondered.

[Steve Wood]

What makes you think it is "Pretty Lean"?

There are no magic numbers other than timing retard.  This is not paint by numbers or tune by numbers unless one is looking at timing retard.  Tuning varies with the car and the ambient conditions.

As I have posted nine jillion times, for my cars, I keep going a bit leaner until I see a tiny hint of timing retard at the top of third gear, then I add a couple of percent back in for a margin of safety on the street because conditions vary so much.

In the end, it's your car, we cannot give you a number (altho some clown probably will).  You have to decide for yourself.

[motorhead]

You can inject alky/water pre-turbo and improve/extend the efficiency of the compressor map.

[Scoobum]

Got a chance to do some tuning today. Ive got overall WOT fueling set down to 123 (128 default number) and lowest sm reading was 797. Im thinking for a street safe 770 reading I'll end up set around 119. Seems pretty lean but it is what it is. It sure is pulling good as I work on this. I know every car is different but that being said is that a pretty lean setting relative to most? Im not getting any kr so alls well, just wondered.

As Steve said...there's no magical number and every engine is different. One thing you'll find if you're at the track enuf...is ambient air temperature plays a critical roll in tuning.