Reducing lag on gt40r?

[pitbull419]

My block is almost complete. Its 20 over manley rods and pistons.
I will be running 1000cc injectors 4layer mitsu gasket etc.etc.I whave all supporting mods.\
Im ordering my turbo today hopefully.A garrett gt40r
My question is what can i do to help reduce lag on this massive 78 trim with .85 a/r?
I would like it to boost like a turbo somewhere between a .73 and .80 a/r
.85 just seems like its going to have some lag issues.
This car is going to be a street car.I know that turbo shouldnt be on a street car blah blah.
My other car is a street car that runs 11's and im about to sell it so im building this moster.
Hopefully i will be done by the end of the summer.

 

[GVR4592]

It probably a divided .85 A/R, if you use a divided manifold it will probably spool just fine.

 

[pitbull419]

Isnt the gt42r a full t4?
Are you talking about using a t3/t4 divided manifold?
Will it bolt up correct?
Im sorry if i dont fully understand what you saying.

 

[GVR4592]

I'm saying the GT40R uses a divided .85 A/R T4 turbine housing. The divided housings, when used with a divided T4 manifold, usually spool quicker than an undivided turbine housing. I don't think it's going to be that bad.

 

[pitbull419]

Ok i see whta your saying now.
I was lost there for a minute.
This is going on my street car.
You dont think i should have any problems with lag?

 

[wishihadatalon]

Ok i see whta your saying now.
I was lost there for a minute.
This is going on my street car.
You dont think i should have any problems with lag?

Lag is something you deal with when you buy a turbo this size. Define problems? And just because their is late spool doesn't make it not a street car.

 

[GVR4592]

Lag is something you deal with when you buy a turbo this size. Define problems? And just because their is late spool doesn't make it not a street car.

Exactly. You're buying a GT40R, it's a huge turbo, it could be defined as laggy if you're used to a 16g. For some of us it's considered a quick spooling turbo.

 

[definitiveno]

gt42 or bust.

 

[wishihadatalon]

wow oops on the "their" its supposed to be there.

 

[arash15]

My block is almost complete. Its 20 over manley rods and pistons.
I will be running 1000cc injectors 4layer mitsu gasket etc.etc.I whave all supporting mods.\
Im ordering my turbo today hopefully.A garrett gt40r
My question is what can i do to help reduce lag on this massive 78 trim with .85 a/r?
I would like it to boost like a turbo somewhere between a .73 and .80 a/r
.85 just seems like its going to have some lag issues.
This car is going to be a street car.I know that turbo shouldnt be on a street car blah blah.
My other car is a street car that runs 11's and im about to sell it so im building this moster.
Hopefully i will be done by the end of the summer.

there are a few ways to reduce 'turbo lag'. I hope the engine your building is a 2.4. thats one of the easiest ways to reduce 'lag'. if you throw that turbo one a 2.0 setup another option you have is to add a shot of nitrous so you can achieve boost faster. if nitrous isnt an option, you can lean out your a/f and advance timing to help out with spool. good lucc!

 

[pitbull419]

Can one off you give me a ruff estimate of about where i will hit full boost?
Thanks for the info guys.Keep it coming.

 

[pitbull419]

No its for a 2.0 im not into the whole stroker scene.
Nitrous never i hate that stuff.
I think i will be able to get away with the gt40r with a little lag.As long as im not going to have to go to 8,000 rpms to hit full boost.
But still the boost this thing will put down off the line will kick a$$

 

[unlmtdndeavor]

why do you hate nitrous? it's one of the best tools you have in helping with spool

 

[turbo addict]

From what I was told, the divided turbine housing besides keeping the pulses separate the a/r dosen't count the material dividing the scroll (the metal in between). So the actual a/r is a little smaller.
Also in my opinion, as long as you don't drop out of boost between gears your fine. Just rev a little higher when you start to race.

 

[nightspeed87]

there are a few ways to reduce 'turbo lag'. I hope the engine your building is a 2.4. thats one of the easiest ways to reduce 'lag'. if you throw that turbo one a 2.0 setup another option you have is to add a shot of nitrous so you can achieve boost faster. if nitrous isnt an option, you can lean out your a/f and advance timing to help out with spool. good lucc!

What he said...
And why dont you like strokers, on a awd street car not spinning more than 8 thousand rpms I cant think of a better way to go. On a balanced bored stroked engine done correctly you could probably see about a 1thousand rpm decrease in spool time.
And on a street car I dont agree with nitrous, but at the track hell yea , it does wonders.

 

[pitbull419]

I dont like strokers because i have never built one.I want to get building 2.0's down to a science before i try to tackle the stroker thing.And since i wont put a motor in my car i didnt build, no stroker.I like the satisfaction of building it myself.I think 2 more 2.0 builds and i might try the stroker.
As far as nitrious?Not on a street car no way

Anybody have an idea of around where i might hit full boost?

 

[nightspeed87]

Well i think you need to get practicing on that stroker, cant be that much different to be honest, its just bending the oil squirters out of the way a little and installing it i think.
And this one guy i talked to with a 2g awd talon had a 42r and he said he got full spool by 4600 or something but I dont know what internals he has so guess that doesnt really help.

 

[pitbull419]

Do you know if he was running a stroker or a 2.0?
Full boost around 5 grand?Thats not that bad considering the boost i will be putting out.

 

[tkelly27]

If you're not using a header with a split flange you could try this...

http://www.theturboforums.com/smf/index.php?topic=45148.0

Or you could change out the turbine housing.

That is of course if you're not getting the boost to come on when you want.

I'm not a big fan of nitrous either.

 

[pitbull419]

Ya i like the idea about the valve.Pretty smart.
But i think going with a split flange i should be ok.

 

[dsm-onster]

See Twincharger v2.0 teaser...Photos inside. More volume displacement than a stroker (upwards of 3 litres). You can keep your built 2.0L which has better rod/stroke ratio for higher rpms. This will also guarantee that you won't be operating at or near the surge limit.

Ray got his 18G to 8 psi by 1500 rpms

 

[JOEY A]

I dont like strokers because i have never built one.I want to get building 2.0's down to a science before i try to tackle the stroker thing.And since i wont put a motor in my car i didnt build, no stroker.I like the satisfaction of building it myself.I think 2 more 2.0 builds and i might try the stroker.
As far as nitrious?Not on a street car no way

Anybody have an idea of around where i might hit full boost?

I have alot of fbody and mustang guys spraying there daily drivers, 1996 maxima with bolton spray and a 5speed with a 75 shot. A hatch with a 75 shot, I can keep naming cars and fill this page up that I know are spraying....


Why not a stroker, I do not understand your logic in this thread....Not trying to sound like a ass but a GT40 isnt a easy/ plug and play setup....alot of things need to be matched correctly to have a good running car

 

[twicks69]

You will likely see full boost in 3rd gear on the street by around 5000rpms or less with a 0.86A/R flange.

Why do I say this??? Well, I run a 4088R with a 0.96A/R divided flange and a DNP manifold, on a 2.3L stroker 9.0:1 piston setup and see full boost well before that.

It is easily streetable with a 2.3L. It will only be like 400-600rpms slower to spool than the 2.3L, and you will have the spool advantage of the smaller turbine housing. It will still easily make 600+AWHP before 32psi.

 

[Mark90gst]

6k full boost 40psi~4088r 2.0l dnp mani. and thats that, turbo suxs, laggy on spool, my bb-t-72 wipes it up on top and spools quicker.

 

[nightspeed87]

Do you know if he was running a stroker or a 2.0?
Full boost around 5 grand?Thats not that bad considering the boost i will be putting out.

Yea thats why i said it wasnt much help to say that because I dont know his internals, he just said it was built, and he was running around 30lbs that day, and then he ran a bad time because something messed up on his car .

I still think you should go 2.3 bored .40 over or something.
Especially on a street car, would be the best route, youd probably have a solid power band from 4-8k in the stroked motor with that turbo were as youd be trying to
turn 5-9k rpms on the street in the 2.0 to make that power...