9 second turbo suggestion (Again)

[karolko]

Hey boys,

I know i have asked this before, however my goals have changed a little, so i am going to try to tax your minds once more.

here is my combo


235 ci 8.5:1
212/212 roller cam w/ 1.55 t&d rockers
champion irons,
champion race intake,
96#ers
Fast XFI
3.5" downpipe

As for headers, i have recently sold mine, so i am debating on 3 or 4 bolt headers. You boys have stated that i am leaving alot on the table with a larger turbo and 3 bolt set-ups,

Converter, well currently i am running a 3200 lock-up on my 200 4r, but will be switching to a turbo 400 in the future, so the stall can be changed.

The thing i am mostly concerned about is streetability. I want this this to spool up quick and go like hell. I am not limited by class, and i plan on running nitrous assist to help give the turbo a bump.

My first question is would it be detramental if i were to stick a 70 or 71 dbb onto a 4 bolt? Should a 4 bolt setup be reserved for 76 or larger turbos?


Thanks alot for the help guys, all i need to do is kill the local liengenfelter in town


adrian

 

[KevinB]

I'd go with a 70. My engine is 234" with a 70 gtq...spool time is pretty good on the street too. Not sure of the stall, buts it is not loose.

 

[trbochrgd1]

I like my GTK-850. It's a 72 mm 4 bolt BB Turbonetics turbo.

 

[bison]

Any 4 bolt GTQ/HPQ should get it done the easiest. Id forget about 3 bolt if your buying headers. Id go for the 70 myself. You will need a converter adjustment or replacement.

 

[trbochrgd1]

I ran 9.91 @ 17 psi with this turbo and @ 22 psi ran 9.56....easily:wink:

 

[Alky V6]

You all need to read his first post again.

He plans on using nitrous for spool assist.

That opens a whole new world of possibilities.

Be careful with using too small a turbo with nitrous assist. You could end up with a combo that spools too quick. Cylinder pressure issues.

IMO a max street turbo would be a T76. With your config, it would run very efficiently. With nitrous, spooling it will be a non-issue. You should be able to stick with the 3200 stall too. Less would be better. When I had my T76 on there, my T/C was stalling at 2440 rpm. The nitrous had it up to 16 psi in .4 seconds.
You're problem won't be how long will it take for the turbo to spool. You're problem will be dialing in the nitrous so that it deosn't spool too quick. You'll probably want to use less nitrous than me.
Use a .8x a/r housing.

Shopping for new headers? 4 bolt.

 

[Alky V6]

In case you misread that last post, 16 psi in 4 tenths of one second.

 

[karolko]

Hey Donnie, i know it will take some tuning, but i am sure that i could tune in the nitrous properly with the XFI.

Also, a 76 is large, but when i would be driving it on the street without using the nitrous, how doggish would it be?

How often do you have to refill you nitrous bottle when using nitrous assist. I know that the nitrous is on for a very short time, but i hav e no idea how long it would last.

16psi, in 0.4 seconds!!! wow. that is nearly instantaneous! i am sure it will be a matter of keeping it on the ground that will become my problem.

what type of E.T's have you run with your setup?

 

[S2V6RACER]

70 GTQ or a one of the new BB turbos from Precision. The fastest TSM cars run PTE turbos for a reason, they make BIG power. After tuning and riding in Bamfords TSM car I was more than impressed with the spoolup and nitrous is just not needed.

He ran over 150MPH in the 1/4 at 26psi and we could not keep the slicks hooked up on the street with more than 19 so keep in mind how realistic it is to use the power you develop on the street.

 

[karolko]

ted. A, you are absolutely correct when it comes to usable power! if you cannot plant it down, then why have it there to brag about.

If i remember correct, i think that dusty's car is a 270CI motor, so spooling a 70 with those extra cubes will make a noticable difference. That is why i was thinking of offsetting my lower compression, and displacement with nitrous.

 

[Alky V6]

I'm wondering something, and I don't have any experience with it so maybe someone can answer this. Running a quick spooling 70 on the street and climbing a fair grade, we have those around here, would the turbo be making a fair amount of boost when we don't want it?

I have had customers that have these turbos that spool insanely quick and early in the rpm band. To the point that it's an annoyance. They suffer from detonation problems in the low midrange because these things are spooling on the slightest uphill grade. That would drive me crazy if it were my car. You don't need the boost coming in so easily that you're heating up your engine with normal commuting. I may be wrong. Let me know how this is working with you guys.

Without nitrous. 5 psi at 3200 rpm w/.82 a/r housing in about .7 seconds. Off the nitrous the power ramp up is tame. I'll post a link to a vid I have of when I had my T70 on the car without nitrous. The rollout was slow because I was using the low stall T/C. It was a test run before I started throwing nitrous into the mix.

Having a setup with or without nitrous that hits too quick will give traction problems on street tires on the street. Using a relatively larger turbo and using nitrous will allow you to easily tailor how quickly the turbo comes in. And when off the nitrous, you can climb grades without the boost creeping in on you and heating your intake air. Heated intake air in the midrange, climbing a grade gets you closer to detonation and makes tuning the midrange correctly a priority.

 

[Alky V6]

It took me a season of racing to go through two 10 pound bottles.

With the T76 I went 9.19 in the quarter with a 1.28 60 foot. Well prepped track and slicks.

 

[karolko]

Don, the 76turbo, what is the psi sweet spot for this turbo. I would like to run this turbo in the 20psi range on the street (and hoping for around 500hp at that psi level) Would this particlar turbo be too doggish at these lower boost range?

9.19 Wow! what boost level were you running at to hit those numbers?

Thanks for all you help.

Adrian

 

[Otto J]

Looking at his combo I would never recommend anything larger than a 70,Its just not needed.The Precision 70 GTQ has proven to go 9 flat on race cars and with a PROPERLY setup car will run 9s with ease.
The Dual bb unit and a proper convertor will spool great without nitrous,Throw out the whole nitrous idea,its not needed(well atleast for spoolup )
As Bison said,If your buyin headers go with a 4 bolt turbo with a small a/r housing.
Michael,don't take this wrong but IF I remember correctly your car is quite a bit lighter than most which makes a huge difference in obtaining a 9 sec or faster pass. I just don't want people to get false hopes using your turbo and boost levels if they have full weight cars.

 

[Otto J]

I have had customers that have these turbos that spool insanely quick and early in the rpm band. To the point that it's an annoyance. They suffer from detonation problems in the low midrange because these things are spooling on the slightest uphill grade.

This is more of a tuning problem than a turbo spoolup problem If you have control of fuel and timing maps.
I cant say I have ever had a problem like you state.
If your timing and fuel tables are relative to boost you should retune the maps in these area,If your finding detonaion with anything less than 20#s on pump you have something wrong.
But im sure you will have a reason something to contradict me

 

[trbochrgd1]

You all need to read his first post again.

He plans on using nitrous for spool assist.

That opens a whole new world of possibilities.

Be careful with using too small a turbo with nitrous assist. You could end up with a combo that spools too quick. Cylinder pressure issues.

IMO a max street turbo would be a T76. With your config, it would run very efficiently. With nitrous, spooling it will be a non-issue. You should be able to stick with the 3200 stall too. Less would be better. When I had my T76 on there, my T/C was stalling at 2440 rpm. The nitrous had it up to 16 psi in .4 seconds.
You're problem won't be how long will it take for the turbo to spool. You're problem will be dialing in the nitrous so that it deosn't spool too quick. You'll probably want to use less nitrous than me.
Use a .8x a/r housing.

Shopping for new headers? 4 bolt.

Don, I did read the first post. I figured with him having less cubes then I, the nitrous would be a good compliment to spool the turbo and it may not be needed all the time on the street. I am not an expert on this, just giving my opinion.

 

[Otto J]

Don, the 76turbo, what is the psi sweet spot for this turbo. I would like to run this turbo in the 20psi range on the street (and hoping for around 500hp at that psi level) Would this particlar turbo be too doggish at these lower boost range?

9.19 Wow! what boost level were you running at to hit those numbers?

Thanks for all you help.

Adrian

We have seen the PTE 70GTQ go 9.0 @ 150 on multiple cars weighing over 3500#s and running 28-30#s of boost.

Don's car is another car that is way lighter than the average Buick will be.
So unless your car is weighing less than 3300 with you in,Both Don's and Micheals cars will be faster at lower boost levels.

 

[wbrophy]

:smile:

 

[Alky V6]

Don, the 76turbo, what is the psi sweet spot for this turbo. I would like to run this turbo in the 20psi range on the street (and hoping for around 500hp at that psi level) Would this particlar turbo be too doggish at these lower boost range?

9.19 Wow! what boost level were you running at to hit those numbers?

Thanks for all you help.

Adrian

That was at 22 psi with the 11.25:1 engine. 24 psi with the 9.25:1 engine. My engine runs on pure alcohol, so ignore the CRs.

Otto's correct about the 70. These days they have smaller turbos that are putting out more than my old T76 Q trim did.

If you don't use the nitrous and you get all setup for quick spooling, just don't make it spool too easily. Like I said earlier, I've driven customer's cars that were setup that way and it just plain drove me nuts having the dang thing spooling in driving situations when there was no call for it.

 

[trbochrgd1]

Looking at his combo I would never recommend anything larger than a 70,Its just not needed.The Precision 70 GTQ has proven to go 9 flat on race cars and with a PROPERLY setup car will run 9s with ease.
The Dual bb unit and a proper convertor will spool great without nitrous,Throw out the whole nitrous idea,its not needed(well atleast for spoolup )
As Bison said,If your buyin headers go with a 4 bolt turbo with a small a/r housing.
Michael,don't take this wrong but IF I remember correctly your car is quite a bit lighter than most which makes a huge difference in obtaining a 9 sec or faster pass. I just don't want people to get false hopes using your turbo and boost levels if they have full weight cars.

Your right Otto, my car weighs 3280 with me in it, so add 320 pounds to it, would it not still be in the nines @ 22psi? (with a properly working converter too:wink: )