Reducing lag on gt40r?

[BrokenTsi]

Even tho my 3082r fails in comparison to a GT40r, I hit full boost at 4900 and I think it spools REAL quick. I wouldn't mind a turbo that hits full boost at 5500, which I think a GT40r will spool at. Hmmmm, maybe I'll go buy one.

 

[nightspeed87]

( If i were awd with a lot more money )
Id love to do like a 2.4 on a gt35r, cams,
fully built and possibly get full spool around 4000-4500
with 7.5- 8k rpm shifts.

 

[pitbull419]

Im back.Sorry about that my keyboard took a shit on me.
Im still wanting to go with the gt40r.
I think im going to fab my custom o2 housing with an atmo dump in hopes that will help a little with spool time.
What do you guys think?

 

[2gAWDTalon]

Im back.Sorry about that my keyboard took a shit on me.
Im still wanting to go with the gt40r.
I think im going to fab my custom o2 housing with an atmo dump in hopes that will help a little with spool time.
What do you guys think?

How would that help spool?

 

[wvturbo2]

Just get a 35R. It will make plenty of power and won't spool as late. You don't seem very open minded for someone that wants to reduce lag on their turbo. Everything suggested you rejected.

 

[BrokenTsi]

Im back.Sorry about that my keyboard took a shit on me.
Im still wanting to go with the gt40r.
I think im going to fab my custom o2 housing with an atmo dump in hopes that will help a little with spool time.
What do you guys think?

I dont think it will be as laggy as you think. Just put it on and drive it. I'm sure it will be fine.

 

[pitbull419]

I know its not going to be super laggy, but it is going to have a lot of lag.
So im going to do everything i can do berfore i get it running to help with lag.
SO far im going to run a custom o2 with atmo. dump.Im thinking about running water/meth injection also not positive about that yet tho.

 

[GVR4592]

I think if you're concerned about the lag you should've gone with a smaller turbo. There isn't much you can do to significantly reduce turbo lag. You might be able to knock off a couple hundred RPM's, but that's it. I would just put the turbo on, and if it has too much lag, get a smaller turbo.

 

[2gAWDTalon]

Before you mentioned that a custom o2 housing with the open dump would help spool... how?

 

[My91TalonTSi]

I know its not going to be super laggy, but it is going to have a lot of lag.
So im going to do everything i can do berfore i get it running to help with lag.
SO far im going to run a custom o2 with atmo. dump.Im thinking about running water/meth injection also not positive about that yet tho.

Neither of those mods are going to help reduce lag. The O2 dump may prevent some creep issues and the meth/water injection will help with knock by reducing intake temps and allow for a more aggressive tune with more timing.

I think one of the earlier posts summed up all your options nicely:

Originally Posted by arash15
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!

 

[Slow99x]

The onlt way that would help would be if it was a cutout and no exhaust. The atmosphere dump does nothing for spool if you are reffering to the wastegate. By the time the exhaust from the wastegate can interfere with the exhaust flow, you are already in full boost. I have never seen a "non custom" o2 housing for a GT40R that has an internal wastegate. If you have a devided turbine housing you should be running two wastegates and atmosephere dumps anyway. You can run a single wastegate but it is better boost controll with two. There are many threads about that subject so I'll leave that alone.

 

[lordnikon_04]

Sell that afc you're using, go buy dsmlink, and then use their antilag feature. That's what it's there for

 

[Maglin]

I'm only going to hit on a topic already mentioned in this thread. If you are looking at getting a 40r what do you consider lag? Usually when someone asks me about what turbo they should run and immediately follow with "but I don't want lag" I tell them to get a E316G. It's small and not "laggy" by most peoples standards.

Lag is opinionated. Very much so. Some think spooling @ 4K is laggy. Others (a small few but they are making power) @ 5K. I personally don't care. If you are not making 500 HP now and are looking to "bolt on" a GT40r and make 700 HP then don't come here asking "how do I reduce lag". You should be asking "what fuel mods do I need". And "what size injectors should I run".

Looking at your profile you are not even close to ready to run a GT40R. One 255HP is not even close to enough fuel pump. You would have to run 2 or get a in-line Bosh. Or do it nice and get a fuel cell and A1000 fuel pump. You don't have enough injector. An AFC won't cut it. Dude spend your money on the stuff to be able to run a turbo like this. Kept the V-trim.

Upgrade your fuel system. Get a stand alone. Definitely get a WBO2. IF these are items you don't want to buy then don't waste your money on a GT40R. All you are going to do is run it at a low boost level like 22-25 PSI. It will have more lag than a GT30R and put out around the same power level.

I'm telling you this not to be rude or cut you down. It's that you are not ready for this turbo. It's a waste of money and you will most likely end up hurting the turbo from surge issues from running to low a boost level and totally flush your money down the toilet. Get at least some 850cc injectors. Get more fuel pump. Get stand alone or DSMLink at least. Get WBO2. That is around $2.5-3K in money right their. If you have this stuff update your profile. You would want to run that thing at 30+ PSI levels.

 

[pitbull419]

Maglin,
Not tyring to be rude
but if you read the whole thread you would have noticed the car with the v-trim is being sold.Along with everything else on it.THis is for the car im currently building.
If you would have kept reading you would have seen im going to run 1000cc injectors i might switch to 1600 not sure yet.I will also be running dsm link and wide band.
As far as fuel pumps im going to fab up a custom dual pump setup.
As far as what i consider laggy.I didnt consider my gt35r laggy.What will the lag be like compared to that?

 

[damnslowtsi]

if nitrous isnt an option, you can lean out your a/f and advance timing to help out with spool. good lucc!

Did you mean retard timing?

Also, pitbull can you explain more about atmo dump on the o2 housing of a gt40? Do you want to have an open exhaust at the o2? That whole thing sounded like you were talking about a Mitsubishi housing? A garrett gt housing only has turbine exducer outlet on it. Thanks.

 

[pitbull419]

Yes im going from o2housing to side exit exhaust.
No cat,muffler will be replaceable with straight pipe for track.

Any thoughts on lag compared to a gt35r?

 

[damnslowtsi]

It should be a little laggier than 35 since it is a bigger unit. There were a few estimates given and they seem to hover around 5K give or take a bit. Compare that to the spool you have on your 35 and you 'll have at least a rough idea.

You never mentioned what exactly you are looking at, 88 or 94. Obviouisly, there will be a few hundred RPM difference between the two. If you settle for the smaller of the two then I 'd look into 751470-5002 part number. That particular unit has better cold side. 4088 itself has a couple of flavors.

All in all you should be all right. Yes, strokers would spool it a bit faster. A 1K rpm advantage in spool seems a bit exagerated to me though. Usually in the real world you see more like 4-5 hundred or so. The fact that you can spin a 2.0 a bit higher thus having better powerband often gets omitted as well. Search around as well. The info is out there. By reading a few decent threads you 'll get the mental picture of what it is gonna be like more or less

 

[94Jettameowpsst]

If its a street car consider the extra lag as being a gas saver. Lag is WAY overrated and if you're having a built motor done i wouldnt worry about it at all.
I have not run a 40r but compared to a 35 i dont think, depending on the ar, there will be that big of a difference at all.
Lean it out on the low end and increase timing to reduce spool up if thats what you're worried about.
Id personally recommend a 255hp and a bosch inline fuel pump just because 1, its easier, and 2, bosch has an outstanding reputation for being reliable and such.

What kind of power are you planning to make on a daily basis? If you gut your car you could most likely go mid 10s on pump.

 

[pitbull419]

just looking to break into 10's on a dd setup.