I'm launching my car at the track but the turbo doesn't seem to come on for 100ft or more out of the gate - is this because I have too much gearing?

I believe the gear to be 3.73 right now and the turbo has an a/r of .68 - I was under the impression that boost is going to come on very fast on this car but so far i've not seen it.

I'm running a 3000 stall converter in an AOD trans but running out of gear at the end of the track.

I have a set of 3.27's that need to go in but i'm trying to make sure that there's not something else going on here - I cannot cut any better than a 1.71 60' which is what the car was cutting n/a.

I'm also installing a mallory hyfire VI with built in 2step to see if I can launch with boost but i'm really stumped on why it takes so long for the car to get going.

 

You need some time with a tuner like myself to get all your systems sorted out. What part of the country are you in?

 

I'm in NEOhio


The rear gears aren't affecting spool time at all then?

 

How are you launching it? With no trans break a 2 step is esential IMO. If you can foot break it to say 2600 rpm or so you can activate the 2 step at the point just BEFORE you push though the brakes. This will be the best launch RPM for your setup. Try the 2 step and see how well it works. Good luck.

 

I think that the reason people ask questions like the original poster did is because they either don't have the money, or would like to make the car run right themselves.

Jess

 

Also check for any exhaust leaks. I had one and when I fixed it my spool time was way better. Similar setup to yours.

 

The car is already tuned, on the dyno and runs great. I'm merely trying to get pointers on lowering the 60's at this point. The turbo seems to come on about 100' out of the hole - being that this is my first turbo, is this normal? Will the 3.27 gear help with spool time? I have a 2step but have not used it yet.

Thanks

 

I just enjoy helping other racers out and if he was close enough I would go ther to see what I could do for him. I normally only charge the pro teams.

Tuning a car for launch is a complete other system. The car should be leaving on boost. I would assume that all boost leaks and exhaust leaks would have already been tended to. One thing I would check is to make sure the wastegate is not stuck open a little. Is the dump tube where you can check it while the car is running to see if exhaust is coming out of the dump tube.

Also can you give us an idea of what turbo, engine and trans you have?

 

Thank you guys for the help here.

Combo:

306
E303 cam
Boxed upper intake/Stock lower (I know )
TEA Twisted Wedge
70mm TB
Quicktimeturbosystems kit w/Precision PT6776h .68 9lb spring

AOD
DirtyDog 3000 converter
SilverFox VB
3.73 gear

Car is roughly 2950 w/driver

http://videos.streetfire.net/video/1137-New-Best_173786.htm

 

that turbo should be spooling without an issue on your set up. Check the wastegate to make sure it is not stuck open. If everything is out there and you have no boost leaks it may be in the timing map. Can you put it on the converter and see what timing cell it goes to after a few seconds of stall. Post what those number are it may just need a few degrees more timing there to help it get up on the converter.

 

With my timing locked at 23, my car ran the same 60' times as N/A. It was not making boost for at least 40'. I have heard of cars with too much gear not making full boost in 1st gear. With a 2 step and boost retard my car makes about 2.5lbs with the 2 step set at 2200. I tried 2400, but could not hold the car back with a 3200 converter. I hope to get it to the track soon and see how much it helps.

 

Problem solved, use the two step!

 

Installed today - button next to the stock shifter.

 

That will help out on the spool!

 

Someone else already said it, but check your wastegate if your problem still persists. If its stuck open it will cause a slow spool.

 

You should be able to spool that turbo free reving in neutral....there has to be a exhaust leak before the turbo somewhere... is the fire ring installed in the wastegate properly ?

 

You absolutely need to bang this thing off of the chip to make boost down low.

Try it and get back to us.

 

Are you foot breaking on the launch? When I read your original post I assumed you had a MPT70 w/.68...those things make boos off idle.

Since you are running a larger turbo I would definately leave on the 2 step.

 

Using a single stage retard on the line will help spool even more. I have a stick car with 3.73's, before with no igntion box I would leave the line @0psi and wouldnt spool until I pulled second (GT-42) ( ) Later I put on a Digital 6 Plus and utilized the 2 step in the pre stage bulbs and once I got into the stage bulbs I would activate the single stage retard @9.9* degrees with the clutch pedal and I left on 10psi (fully spooled) 60ft's went from 1.8's to 1.4-1.45 range. If your Box has a built-in retard use it on the line!

 

You only retart the timing on a clutched car to build boost. Automatics are the exace opposite!