Was needing info on a stick car turbo combination. My question is how to build boost on the line with the stick since there is no load on the motor with the clutch depressed? I have heard of using a two step rev limiter to load the motor and build a small amount of boost on the line. I am not worried about building max boost at launch since i feel that my combination should have enough grunt to get itself rolling rather handily until the turbo spools completely. Here is my combo: 89 hatchback with a 380 cubic inch SB2 headed small block Chevy with a 91mm Innovative turbo and a Doug Nash five speed with Long vertical gate shifter and a Mcleod soft-lok clutch. Also while I am at it: Any opinions on boost loss when shifting? I plan to run a Godzilla bypass valve and with the vertical gate shifter I dont think that there will be enough lag between shifts to deter boost but I just wanted some opinions. ANY help will be welcomed!!

 

2 steps work great at building boost. If you were wanting to make a lot of boost, I would say that you can include a timing retard in with the 2 step as well, but it sounds like just a 2 step would work fine for you. About loosing boost on shifts. As long as you can shift fast, you won't have any problems. If you're really good, you'll be able to shift without opening the bypass valve.

 

Sheesh I have traction issues when powering higher than 1800 rpm!! Anti lag can help if built into ecu...Basically thats two stage...

 

speed shift it and you'll never loose boost. if your not familiar with that, basically you never let off the gas. hold the trottle down for the entire run and when you need to shift, you pretty much just kick the pedal in real quick while you shift. get ready to pull or push the shifter right as your kicking the pedal. the motor will rpm higher a bit between shifts and a rev limiter is definatly good here. id suggest trying this on some type of daily driver first.

when my car was N/A, i dropped over a half a second speed shifting it over letting offand shifting and back on the gas. oh, BTW, its hard on parts (like racing isnt anyways) but it sounds absolutly wicked when you get it right

 

There is alot more to this than a 2 step. A two step or three along with the right EFI tune will get you what you are after but just putting it on the limiter will not work.

 

Two step with turbo anti-lag programming of the AEM

 

i plan on running twin GT28RS ball bearing turbos for my v6 and I do have a 5 speed. I can setup my 99 v6 stang using sct software to do a two step stage setup. Do you think the two step will destroy my turbos? These are fancy ball bearings that I don't want to crack the turbine wheel.

I have a v6 so I definately wanna have boost off the line. I don't got the torque displacement off the line like you fancy v8 guys do

 

A little bit of N20 helps...I think you'll find a 3 or 4000 rpm launch will soon spin those turbo's up...Traction permited....Even though @ 4000 rpm free reving those turbo's are still moving air, boost will rise as soon as load comes on very quick.Hopefully enough to allow some traction.....

 

I have made 5-6 psi of boost with the 2step on a 5 speed 302 with a 60mm no problem. If you can pull the timing back to 0 degrees that will realy help build boost. and I have a nitrous selinoid in the line going to the wastegate so you can block the signal on the starting line to help build boost. If you think about what is taking place on the starting line .....You are trying to make boost as the boost starts to rise the wastegate is lifted off the seat allowing it by pass exhaust gas and even with 2 psi are so the waste gate is already trying to slow down and control the boost. If you block the signal to the wastegate you can have 100 % of your exhaust routed to the turbo and not begin to open the wastegate. After the boost reaches the desired level you can allow the signal back to control the wastegate.

Just my .002

 

Using my 2-step along with the timing retard tied together netted me 5-6 psi of boost within 3-4 seconds and this is with a old school dinasour carbureted system. Nothin' fancy at all.

 

I used to get 8 psi around 4500 rpm on a 2-step, no timing retard, etc.

 

Gentlemen--I have exactly the same question but a different combination. I am converting a nitrous car to turbo plus nitrous. Mine is a 3500 lb car with a 283" DOHC engine. With a 150 shot, it will do a 1.35 60' at 3500 lbs with a TKO-600, launching at 6800 rpm, with 28" tires and a 4.56 gear.

I am putting in a GT-40 single turbo on a forged 9.0 compression motor. I have the SCT Pro Racer Package and can do whatever I want with a two step and timing retard.

I am not going to be happy if I can't hold the same 60' that I have on the juice. I will run a 100 shot or so with the turbo if I have to to make the car launch.

How much timing retard should I try?

Thanks, this is a "learner" turbo, and I am going to learn how to make it work.

Joe

 

Joe, You'll just need to experiment. You're lucky in that you already know the car hooks. So you can two step it wherever it takes it to make the boost needed to duplicate that. Also, some cars don't need to retard the timing.

I'm still of the opinion that you should have tried it with the high compression motor. You do have the ability to tune the thing, so compression isn't really an issue. You should see what some of the turbo Outlaw 10.5 guys use(hint, hint 10.5 to 11:1 in some cases).

 

Shane--thanks for the note, glad you are still checking the forums. It isn't too late to try the high compression, I will have the heads off the motor by Thursday to take a look at the pistons. My goal is to have the motor in the car again for two years without taking a valve cover off, same as when I built the nitrous motor.

I guess I will try the two step first without timing retard and see what happens. Then the small shot of nitrous. Then a little timing retard on the two step. Then a bigger shot of nitrous.

I really want to hear the itty bitty Ford popping and banging at the starting line like the big boys do!!

Just kidding. Thanks again. Pics later this week of the pistons.

Joe

 

I think I'd shoot for 9.8 to 10:1 for compression. Ed and I were at 10.5:1 last year. It took all the timing we threw at it.

BTW...... the car is going back together for Clash of the Titans next year with twin GTS76s.

 

Here is the engine out of the car.
http://www.joelynch.org/engine2005/engineout.jpg

Here is a video of the nitrous car at Penwell
http://members.cox.net/joelynch11/072905allruns.wmv

The engine is running about 1.4 ratios richer than indicated on the wide band in that video, by the way.

Why do people run 8.5-9.0 compression on the wedge head Windsor motors? Do you think the open chamber with the DOHC engine will allow 10 and run OK on the street with the turbo?

Joe

 

Yes 4 valve motors can run alot higher compression...Especially with tuneable ecu...

 

That's great!! Did you break your skis?

Joe

 

Another point brought up by xr8tt. Gearing. My car currently 60's pretty good on the juice with a 3.27 low gear and a 4.56 rear. Why would this be considered too much gear with a turbo when it works so well on the nitrous?

Joe

 

Nitrous doesn't need load to build power, depending on tyre size and auto / trans? 3.45 or 3..7 final drive for turbo seems to work..
The more they're loaded up the longer and harder they pull in each gear....