how to reduce turbo lag

[2gmummy]

I finally got my new turbo set up on and it is a beast up top but out of boost not so much. Its a bw s256 and i want to make it spool faster, right now i have 272 cams and i was thinking about going 280s along with my 2.4l stroker block with hopefully 10.5:1 compression on e85. I also have an old venom intake manifold just sitting around i could throw on. Will these help lower turbo lag? What else can i do to spool faster? Also i dont want to lose torque and bottle are for babies

 

[Imback]

280's will increase lag as well as a smim. A stroker will certainly decrease lag.

 

[BrokenTsi]

With the exception of swapping to a 2.4L block, all those things you mentioned will hurt spool....but it will make you faster.

What does it spool at now?

 

[2gmummy]

So stick with the stock manifold and 272's and it spools at like 3k-3.5k ish and I thought higher compression will help?

 

[talonDSMerr]

Higher compression will help off-boost power. When you have the 2.4L, you will hardly notice any turbo lag. The off-boost power my 2.3L makes from 2200 up until the turbo spools is night and day compared to the 2.0L before.

 

[RT-AWD]

3-3.5 is very good spool, that's where i start getting boost with my Kelford 272s and 50-trim. maybe you need to mess with your timing because my Talon is peppy as crap even when it isn't in boost. 2nd gear a 2.5 if i floor it, it'll send you back in the seat a little annnnd then a lot.

 

[2gmummy]

Well im use to my 16g that spooled at 2200 so i guess im just not use to it yet. How else can i help off boost power? I loved the low end with the 16g but i love the top end on the new turbo. I know i will never spool as fast as the 16g but if i could come close...!

 

[newTSIguy]

You had a 16g that spooled at 2200, dayum, that makes me cry,

 

[1990AWD]

Well im use to my 16g that spooled at 2200 so i guess im just not use to it yet. How else can i help off boost power? I loved the low end with the 16g but i love the top end on the new turbo. I know i will never spool as fast as the 16g but if i could come close...!

WTF did you do to spool a 16g at 2200 rpm? My 14b only reaches 20psi at 3400 rpm.

 

[BrokenTsi]

Maybe it only started to spool at 2200...?

 

[2gmummy]

Yea no it started spooling at 2200 and i have bc 272s so they helped as well

 

[RadDsm]

More aggressive cams slow your spool time, not increase it.

 

[airmail96]

You could possible mess with the cam timing if you have adjustable cam gears or do some tunning to try and increase spool up.

 

[Boostinsideways]

The bigger cams (to a cetain point) will actually help spool on a 2.4 or 2.3. But really the only way to increase spool is to increase your exhaust gas velocity. So wrapping your manifold, turbo blanket, increase displacement, or increase compression.

 

[2gmummy]

^ so then would 280s on a 2.4l help or hurt spool? Im kind of confused on that. Ive heard 280s in a 2.4l act like 272s in a 2.0 and my 272s seemed to help me spool? Also if i fabbed up an intake manifold with a large collector like an aftermarket smim with long runners like an oem manifold how would that affect spool/ off boost power?

 

[bryanwheat]

Larger displacement = faster spool.

 

[talonDSMerr]

An intake manifold with a bigger collector/plenum will increase your spool time because the turbo will have to fill more volume in the intake tract. Long runners help low-end torque.

 

[RipperXX]

Things that help low end torque. Note I said more low end, not faster spool. Faster spool with super rich low timing tuning is silly and nets no real gain IMO.

Intake manifolds can hurt or help, depends on the design period. I have seen dyno charts with Hawver cast manifolds, that actually picked up torque in the low end and power up top. It made more power everywhere over the stocker.

Tends to be though, that a manifold with longer runners and smaller plenum will make more troque, fat plenum and short runers makes for shit low end but breaths very well up top.

Intake, beleive it or not, your intake and air filter setup can effect your performance more than you think on a turbo car. As it's pretty common to see 6-7inches of vaccume in the intake pipe. Basicly, just have a good intake pipe with a massive as #### air filter, it will help the turbo to do it's job, be more efficent and heat the air charge a little less.. obviously try to shield it element from the engine bay heat.

Exhaust manifold- Often tubular designs outperform anything cast, but the FP race manifold is a nice in between, more durable than a tubular, cheaper and flows better than a Evo III unit.

Twin scrollTurbine housings. Is there more to say?

If stuck or staying single scroll, a smaller A/R housing will increase spool in most cases, but go to small and you will choke it up top and have excessive exhaust back pressure in the manifold which can lead to back filling of the cyl's and increase the likely hood of detonation/pre-ignition

Largest, shortest exhaust you are comfortable with, manderal bends and as few of them as possible. Cutouts are nice choice too, same effect as open down pipe when open, nice and quiet when closed. Basicly the point here is little back pressure as possible on the post turbine side = faster spool.

Tune-Lower boost as low as you can then tune for a leaner A/F mixture 11.5:1 - 12:1 Once your happy with your A/F ratio, add in as much timing as you can without getting knock. Once you found the knock threashold, back it off 3-5*, slowly begin raising boost back to your target amount. If you can reach it without hitting any knock, add in timing until you do, then back off 1-2*.

Higher timing makes for a more responsive engine that makes more power at any boost level. Example. 27psi @ 10* advance will feel slow and slugish next to 21psi and 17* of timing.

Also like someone mentioned above, adjustable cam gears. Get a set if you really want to milk your engine for everything it's got, and go to a dyno. Advancing normally makes for more low end but hurts the top end, and visa versa retarding normally gets you a few more hp up top but hurts the bottom end power.

Cams Keep them reasonable in size, and compaire more than JUST the advertised duration! IMO GSC S1's look to be about perfect for 70-80% of DSMers out there. 268* cam, 110* lobe seperation, 8* over lap. I forget the rest of the numbers, but they don't lose any low end, but open up the mid and top a decent amount. Obviously im talking about 2.0L here, a bigger engine = bigger cam needed.

Obviously a stroker or 4G64 will yeild more exhaust and spool up turbos much faster.

N20 50 shot

Thats about all I can think of that will help with low end power off the top of my head.

 

[2gmummy]

^ awesome that helped a lot with your afr's are you saying that in regards to e85? And the cams I were talking about were th bc 280s BrianCrower.com | RunBC.com // Mitsubishi // 4G63 link with the specs. And as far as filters i thought size doesnt matter as much as location because regardless of the filter size the turbo can only suck in "x" amount of air at one time? Also bottles are for babies haha so im not running N2O

 

[Evo-Jr]

I know this is a little old, but im having almost the same problem. I dyno my car today and i was very upset with the results.. 2.3 stroker 9.1, t4 housing pte6262 with 68a/r, hks 272/264.. This turbo its super laggy, i dont know if the cams are holding me back or the turbo.

Kind of crazy how i made 460hp at 28psi, and how long it takes to make 28psi Please guys i need some advice before i go nuts.. Feel free to ask me any question if i missed anything....

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[Rocketman1000R]

I have a 2.3 with HKS 272's, stock intake, S90 TB port matched everything and tubular single scroll header with a S256 with the .55 DSM ar. The trick that made the difference was when the tuner played with cam degreeing. Once we deviated from the cam card things happened real fast.

Here is my dyno chart. My DSM had NO lag and is limited by the DSM 55 ar.

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[airmail96]

Cam timing can play a huge roll in how the turbo comes in and how the power is made. Keltalon tested a bunch of cams and messed with degreeing them to get the most power out of them and best spool up and did a really good job posting his results in this post .