Vpro 2 step/launch control

[Abbey M/S]

seems us chaps running manual gearboxes need to step up a little.... a certain Auto boxed Supra went very well yesterday....

[Andy Barnes]

Was he 4WD then ?

You've got to step up, not me

[Abbey M/S]

okay....us 2wd boys......

Back on track then Stony send me a PM with your e-mail addy on I try to help you out

[Abbey M/S]

whoops

[Andy Barnes]

You should be running 6's, that RWD half backended stuff is a doddle, what I need is 4 of them-there wheels, I think I would get a minus 1 second 60ft time with them installed on each corner, Back to the Future revisited

[Stony]

My 2 STEP thing has been worked out… my problem now is my converter stalls WAY too low. We have the 2 step set at 3000 rpm which is where it stalls at and we build 3 PSI. When the brake is released rpm goes to 3300.

The problem with turbo converters is you can’t go to loose to build boost cause if you go too far you will just blow thru the converter if it’s too loose and lose mph.

I have come to the conclusion that I’m going to throw a 75-100 shot of NOS at it on the brake to see how it reacts. If we can get it off the line with a decent 60 foot I’m guessing I may see 160 mph trap speeds. On the dyno we got 160MPH at 9K in hi gear.


Anyways thanks for all the help I will keep you guys updated on my progress.

I will just not be allowed to run in classes that only allow 1 power adder

[R.I.P.S NZ]

Seems your converter is too tight and your not making any torque at such low rpm.

My first converter in the 240z stalled at 7000rpm which was 'OK' but I lost out on alot of top end mph and we just cooked it by 1/2 track.

The new converter was made based on the dyno graphs we had, the weight of the car, the diff ratio etc and we now stall at 5500rpm with as much boost as we like (up to 30psi) and we dropped 3 10ths off the 1/4 time and gained 10mph and we changed nothing else.

The problem then is stopping the car from wanting to flip on its roof so we've found we have to bring the power right back on the line now to get away with any sort of control.

1/2 track at over 130mph is possible with a gentle roll off the line and 162mph top end with a very mild tune.

Get that stall up and give it a 50-75 shot and all will come right.
IMO, don't mess with ign retard on a 2 step to build boost, been there, done that and for us, with the auto it just didn't seem to work.

On a pro tree, if the other guy stages 1st, you have to be able to get right up on boost VERY quickly or you don't stand a chance in real competition.

Good luck, looks like you have some good mph comming your way once its sorted.

Rob

[Stony]

The fuel pump we are using should be able to support what we are doing but for some reason it's not. We are going to add one of these to see if it will help with my fuel issues before adding a new pump. Marren Pro Fuel Damper

With 1000cc injectors supporting 8K+ engine rpm these guys say that it is not impossible for the rail to cavitate if you wanna call it that and not have enough fuel to support the next pulse. which would explain our lean indication.

Then also a 75 shot of nitrous to get it off the line. if that dosnt work then a new converter and fuel pump will be inline.

[R.I.P.S NZ]

What fuel rail do you have now and how is it fed (ie, ins where and out where?)

Rob

[Stony]

Its' fed from both ends of the fuel rail and the regulator pulls from the center. the -8 line splits into 2 -8 lines that go thru to earls inline filter then off to each end of the rail. pretty standard setup

This is all new ground for me. I suspect we will end up changing the fuel pump eventually but we are trying to fix it one step at a time.

here's a pic



here's a pic of where the line splits

[R.I.P.S NZ]

It looks like you have a -8 line that splits into 2 -6 lines which then go through the filters and come out as -8s that then go to each end of the rail?? Is that right or is it hard to see in the pic?

Rob

[Stony]

Yea it does look like in the pic they are smaller diameter but i can assure you that everything is -8

[R.I.P.S NZ]

ok, now we are getting somewhere............

When you go from a single -8 to a pair of -8s you get a pressure drop in the 2 lines.

If it was me, the first thing I would do is go -6 from each outlet of the filters to each end of the rail and run -6 to the reg as well and after the reg whatever you already have is fine.

Try that, it might just do the trick.

What base fuel pressure are you running?

Rob

[Stony]

45 psi. it ramps up to 60 when boost starts to come on then trails back off to below 40.

i ordered a fuel system damper since most stock systems have one and i think i will try the -6 theory.

Thanks for the help.

Are you running a wet shot or dry shot of nitrous???

[R.I.P.S NZ]

Your fuel pressure should be about 45 + boost (psi) and it shouldn't drop away while boot is present.

I run a 75 wet shot to get stall boost and I have a 6 port wet kit but havn't used it on the strip yet.

Rob