drag racing help

[mkoch1]

well I went to the local drag strip this weekend with so okay results. I was running street tires no slicks or drag radials.

Anyway first pass just took it easy and left in 2nd, shift into 3rd go me pretty side ways
r/t 1.359
60 2.090
330 5.540
1/8 8.125
1000 10.327
1/4 12.114
mph 126.49

second pass tired to leave in 2nd motor bogged down then when the boost hit is spun like crazy.
r/t .806
60 2.672
330 6.542
1/8 9.049
1000 11.225
1/4 12.984
mph 129.52

last past tried to leave in first, spun first and second pretty bad
r/t .614
60 2.581
330 5.941
1/8 8.556
1000 10.788
1/4 12.661
mph 120.67

Maybe it's just going to take some time to learn how to launch this thing. Still had a great time just a little disappointing, I know it's got a lot of potential.

Anybody know what kind of tire pressure I should be running on the stock tires? Should I leave in first or second?

mark

[boosted ls1]

Have you a mild or wild cam? Could you delay the boost or make it more progressive?

Boosted.

[mkoch1]

it's a stock 98 ls1 motor. I have a manual boost controller so there is no way to adjust the boost other than up and down.

mark

[gtrclive]

When you say Stock... Do you mean no mods at all ?? not even stiffer valve springs ??? Am very interested in building a turbo motor but don't want big power 500+ at the wheels would be fine.... So am interested as to what has to be done to the engine to make it reliable.... Have you ran this kind of engine before ???

Clive

[eliot]

gtrclive said:

So am interested as to what has to be done to the engine to make it reliable.... Have you ran this kind of engine before ???

Clive

If you keep your boost to around 6psi you can run stock internals on many engines. You will need to manage fueling and ignition mind you.
ETA: Unless your'e running high n/a compression.

Edited by eliot on Monday 12th March 19:01

[mkoch1]

gtrclive said:

When you say Stock... Do you mean no mods at all ?? not even stiffer valve springs ??? Am very interested in building a turbo motor but don't want big power 500+ at the wheels would be fine.... So am interested as to what has to be done to the engine to make it reliable.... Have you ran this kind of engine before ???

Clive

when it was completly stock I ran it at 5.5 psi. Made 413 hp / 461tq at the wheels. Motor was pulled out of a wrecked 98 vett with about 35K on it.

I slapped on a set of partriot LQ9 heads (with dual springs) to lower the compression and upped the boost to 9.5psi. now it makes 511hp / 528 tq at the wheels. Tuner though we could go up to 12 psi. I run meth injection for saftey even though it was tunned without it.

mark

[gtrclive]

Which pcm tunner did you use LS Edit ??... How much where the heads, new or second hand ??

[mkoch1]

the heads where around 1300 US. www.patriot-performance.com/ Most people would rate their heads as ok, good value for the price. I run a electromotive tecIII stand alone computer

mark

[chuntington101]

mkoch1 said:

well I went to the local drag strip this weekend with so okay results. I was running street tires no slicks or drag radials.

Anyway first pass just took it easy and left in 2nd, shift into 3rd go me pretty side ways
r/t 1.359
60 2.090
330 5.540
1/8 8.125
1000 10.327
1/4 12.114
mph 126.49

second pass tired to leave in 2nd motor bogged down then when the boost hit is spun like crazy.
r/t .806
60 2.672
330 6.542
1/8 9.049
1000 11.225
1/4 12.984
mph 129.52

last past tried to leave in first, spun first and second pretty bad
r/t .614
60 2.581
330 5.941
1/8 8.556
1000 10.788
1/4 12.661
mph 120.67

Maybe it's just going to take some time to learn how to launch this thing. Still had a great time just a little disappointing, I know it's got a lot of potential.

Anybody know what kind of tire pressure I should be running on the stock tires? Should I leave in first or second?

mark

nice one mark! think its just a case of getting used to the beast more than anything. your first attempt is the best and you where taking it easy then! once you get it hooked it should fly!

are you still not running any form of intercooler on it mark??? how does the meth do at keeping inlet temps down?? here alot of people using it to supliment an intercooler.

thanks CHris.

[mkoch1]

are you still not running any form of intercooler on it mark??? how does the meth do at keeping inlet temps down?? here alot of people using it to supliment an intercooler.

No intercooler just meth. I don't remember the esact temp drop but after we got done tuning the car we went back and did another pull with the meth, intake temp was way down and it made another 30hp. I think most people tune the car, then use meth to allow for more boost. I tuned without the meth, and just use it for cooling and increased octane.

mark

[chuntington101]

mkoch1 said:

are you still not running any form of intercooler on it mark??? how does the meth do at keeping inlet temps down?? here alot of people using it to supliment an intercooler.

No intercooler just meth. I don't remember the esact temp drop but after we got done tuning the car we went back and did another pull with the meth, intake temp was way down and it made another 30hp. I think most people tune the car, then use meth to allow for more boost. I tuned without the meth, and just use it for cooling and increased octane.

mark

your figures are even more impresive concidering you have no intercooler! so you plan on fitting one later or not? have you looked at the PWR chargecoolers?

thanks Chris.

[andygtt]

The launch makes or breaks a quarter time...... what I did with my Ultima and my old cossie (high power turbo engined car) is sit at a set rev at the lights just enought to get some wheelspin, 4000rpm in the cossie 3000rpm in the Ultima. I'd then drop the clutch but not move my foot until I judged the wheelspin was stopping and then I'd floor it.

This method puts loads of strain on the drivtrain so isn't mechanically sympathetic but was the fastest way to launch for me with road tyres..... its not an exact science though especially with the kind of power you have.

[chuntington101]

good idea andy!

i heard some of the manual turbo V8 guys in the state launch and get great 60foot times. think some where in the 1.6 second area!! a tuner said he would take the RPM upto about 5k, then when the lights go out gently lete the clutch out and gently add throttle at the same time. he even said he would just flex his ankles rather than moveing his left leg!

must have taken him ages to get it right but just goes to show ot can be done with engough practice.

thanks Chris.

[andygtt]

Chris

The problem I found with slipping the clutch to launch fast was that is it overheated the clutch and it sometimes just kept slipping.... yet the big bank approach never resulted in any clutch slip after the pedal was let out.

[gtrclive]

Don't take Andy's aproach I beat him twice with 60bhp less.....and have the video to prove it.... If so one wants to host it I can prove it.... Hay Mark ??

[andygtt]

once with a slower time.

Edited by andygtt on Wednesday 14th March 16:29

[builder]

Mark, I have only driven a couple of high-power 1/4-mile cars...none as light as an Ultima. But, here's my guess at the proper technique:

1) Start in 2nd gear and get the clutch all the way out as soon as possible without high revs.

2) Modulate wheel-spin with the throttle, shifting early into third gear if boost becomes too much to control.

3) If 3rd gear and boost at WOT produces wheel spin, short-shit again into 4th before boost hits.

Little 4-banger drag cars are turning almost 10-flat at 129. But, those are true strip machines. A GTR can't be much heavier, so it's all about the hook-up.

You better take your trailer with you, so you can bring home that extra car you'll win at the track!

[luckyp]

andygtt said:

Chris

The problem I found with slipping the clutch to launch fast was that is it overheated the clutch and it sometimes just kept slipping.... yet the big bank approach never resulted in any clutch slip after the pedal was let out.

Seconded

[tuxman]

my best run was a secong gear start with 4000rpm dialed in drop the clutch and go ,feathered a little in second just to get moving then ran to the red line in each gear ,run 19psi in the rears with my softest springs and damper setting also softened the front as well ,my best 60ft time was 1.997 which is not bad but once i was moving the car just flew hitting the 1/4 in 11,6 3rd and 4th were the most impresive just seem to hook up very well .is there no way you can map the boost down a bit until say over 1/2 throttle ?

[pee]

Goooo on the dragster.