turbo lag.... any solutions?

[Mattheww044]

hey guys i just bought kelly's old radioflyer ss. its got an avo 320 turbo which i realize is huge compared to the VF-11. but the turbo just has a rediculous amount of lag until about 4500 RPMs which almost makes it seem worthless. at about 5k it actually hits and launches like no other... but is there anyway to get that boost before im about to shift? thanks guys

[Aerotech]

Sure, spend $2K for engine management with launch-control and anti-lag ability, which will destroy your valves fairly quickly. (That's the flame-throwin' back-firing system you see in operation on rally cars, it keeps the turbo spooled up by retarding igntion and dumping gas into the intake, turning the turbo into a small jet engine)

Other than that, get a smaller turbo, or learn to live with it... push the revs up to redline on each shift to get any use out of it.

[93forestpearl]

Hmmmm. I can't find the AVO 320 on their website, but the AVO 380 they rate at 44 lb/min. 4500rpm seems pretty late for a turbo that size to hit hard.

What are you using for EM? Timing and fuel can make a pretty decent difference in terms of spool-up.

[Mattheww044]

i know it has a piggyback ECU, but the car is completely built. i didnt build it so im not quite sure on all the specs for it... should i take it to a performance place and have them tune it? if it comes down to it i might just sell the turbo and get a td06. im pretty sure that would do the job. the dude i bought it from said that if i got an external wastegate that would reduce turbo lag. and also he hammered in the DP in order to make it clear the firewall, but some of the guys on here said that that wouldnt effect the turbo lag

[93forestpearl]

Ummmmm, define "completely built." The fact that it has a piggy-back means it is not completely built.



An EWG is not going to improve your spool by that much, if you are looking for 1000 rpm or more.

[555BCTurbo]

Sure, spend $2K for engine management with launch-control and anti-lag ability, which will destroy your valves fairly quickly. (That's the flame-throwin' back-firing system you see in operation on rally cars, it keeps the turbo spooled up by retarding igntion and dumping gas into the intake, turning the turbo into a small jet engine)

Not really how antilag works:

It actually retard the timing and subsequently combusts the fuel in the exhaust system, which in turn spools the turbo...


Highly destructive...


You could just get a 2 step rev limiter...they work very well for boost building...and don't hurt the motor too much

[92ss satinsvoice]

the avo turbo's are known for slow spooling .


get a TD05 18g, that would be a fun turbo. even the 16g is pretty fun too.

[Mattheww044]

hmm... ya i read that the avo 320 costs 2200$$.. which is a bit rediculous personally. i could sell the turbo and buy a smaller one for faster spool and do a bunch of other things to get the car the way i want it.... and trust me its completely built... go to the link in my next post

[Mattheww044]

http://bbs.legacycentral.org/viewtopic. ... sc&start=0

[Kelly]

Its got a vacum leak at the throttle body. I never made a plate to seal it up correctlly, just made a cork gasket. It would explain the idle issue too.

[GodSquadMandrake]

You could go with a ball bearing turbo for quicker spool and keep the same power level.

If you want to keep that turbo...
Port and polish the turbo, heads, manifolds. Gasket match the manifolds and head.
Ceramic coating on the manifolds, heads, and pistons.
Increase compression.
Lighter pistons.

For tuning you could...
Lean it out before 4,500 RPM. More lean is more heat which is quicker spool. Switching to a higher grade of fuel or E85 or water/meth injection can help you accomplish this.
Pull the timing, once again same issues with detonation unless you do water injection, meth, or run higher grade of fuel. Keep your combustion chamber cooler also helps with detonation. Cermaic coatings assist with keeping heat OUT of your pistons and combustion chamber and help it flow into the exhaust.

You could also stroke the engine and increase the displacement that way, that'll decrease spool for sure!

Your intake and intercooler piping has a lot to do with it. People who switch to under the manifold silicone inlet piping report quicker spool, usually around 250 RPMS quicker. Smoother bends or higher flowing intercoolers can help too. I'm not sure what you have but your turbo is pushing the limits of a WRX or STI TMIC.

There isn't too much you can do without changing stuff on the engine. You can fine tune it and that will help, but you have to physically change something to really get a big benefit.

[GodSquadMandrake]

Is this your mods list?

Current mods 6/6/2008

Fresh ej22t
ej20h twin turbo heads (JDM)
AVO 320 turbo
AVO BOV
3" stainless Espilar exhaust
Custom rotated turbo mount
Custom FMIC
440cc injectors
Perfect Power 6 piggyback ECU
Innovative wideband o2
Knock Link
big aluminum radiator

03 WRX 5mt trans
Exedy stage 1 clutch kit
3.9 VLSD rear end
04 WRX struts
Perrin springs
05 LGT front brakes (12.9")?
Deleted ABS
225/45/17 Toyo Proxes
Black Racing wheels
Interstate battery in trunk

And lots of other little bits here and there. Very Happy

It looks really nice! Most of the big stuff has been taken care of already. There's lots of little stuff you can still do though. You could get phenolic spacers for that intake manifold. I have the same manifold and it's pretty bumpy on the inside, you could smooth it out a lot and gasket match it to the block. You could put heatshielding under those intake pipes where they cross under the manifold to make sure they don't get heat soaked from the hot block.
Are your injectors like maxed?! I didn't know you could get 320 HP out of 440 CC injectors.
What kind of exhaust manifolds do you have?
You could port that throttle body. It's really easy to take apart and then you just shave down the bolt that holds the butterfly to make it less round and more flat. You can make it real thin and it'll help with throttle response especially.
Have you ever though of moving the MAF to right before the intake or switching to a MAP sensor? Your PP6 will let you do that. Where you have it now is fine but it adds some lag because the air as measured thru the MAF has to travel all the way thru the turbo and your intercooler. You'll get faster/better response with it closer to the throttle body. OR you could switch to a MAP sensor. I haven't heard of this being that great with PP6 but you could do it and it would help with your BOV too.

[BXSS]

Sure, spend $2K for engine management with launch-control and anti-lag ability, which will destroy your valves fairly quickly. (That's the flame-throwin' back-firing system you see in operation on rally cars, it keeps the turbo spooled up by retarding igntion and dumping gas into the intake, turning the turbo into a small jet engine)

Not really how antilag works:

It actually retard the timing and subsequently combusts the fuel in the exhaust system, which in turn spools the turbo...


Highly destructive...


You could just get a 2 step rev limiter...they work very well for boost building...and don't hurt the motor too much

2 step will work but it can kill your motor too.
If your look @ EGTS while 2stepping you'll see the temp jump towards 1600* quick, hold the 2 step for too long & you'll melt down...

NOS has helped spool many a turbo....

[dscoobydoo]

Welcome to what happens when you buy an already built car.

You now get to spend the money un-doing some of what the previous owner did.

The car was previously built for serious power. this means mostly top end power.
Your spool times move up as the turbo gets larger. also having a front mount makes it spool a little slower due to the further distance the air has to run.

SO, that said, the EASY way to adjust ( as stated before) is to downgrade the turbo.

I would suggest for ease and low cost, to hunt down a VF-39/43/48 off of NASIOC.

Ours is putting down 300/300 on a conservative tune. Full spool is at a decent 3k.

I would also suggest upping the injectors to 565/650s. I think the 440s might be a bit small.

CN: Get 650s, get a cheap VF-43/48 ( or 39 or 18G) and re-tune.

[douglas vincent]

First off, FIX the leak at the throttle body!!!! This will cause issues at idle and then leak boost which causes lagginess as well!


You can tune the PP6 to cause quicker spool by richening up the fuel down low, but you get worse milage.... I was able to move full spool over by about 500 rpm on the dyno...

[Mattheww044]

wow guys this is great im really happy to be a part of this community...

how much $$ do you think i could get for that avo 320? it seems like its a pretty rediculous turbo for a DD. im guessing a vf-39(from an sti correct?) would be more than enough.

the previous owner (not you Kelly) isnt really providing me with the info that im looking for as far as how to turn the boost up. I know that if i get a laptop i can turn it up with the perfect power program. but im confused on how to turn it up manually because there is only one wire attached to what i believe is the stock boost solenoid, so it seems like its not even hooked up.

Im not the most mechanically inclined person on here by any means which probably doesnt justify why i bought this car but i love subarus especially the legacy turbo, so im sure i will learn alot about the subaru motors from having this car.

For the throttle body vaccum leak, is there an aftermarket part that i can buy? or should i just make one/get one made?

thanks for any/all input guys

[GodSquadMandrake]

Look on the turbo, there should be a vacuum line on the outlet side and then it should run to the wastegate actuator. If there is a manual boost control if will be on that line. I wasn't aware PP6 was also an electronic boost controller.

I don't know for the throttle body. I'm not even sure what the problem is.

[Mattheww044]

from what he told me, you can turn up the boost and all that jazz by plugging a laptop into a cord that is ran under my seat... i dont have a laptop tho but he said there is another way to turb it up and he said he would email me how to do that.... it has been weeks and still no email... go figure. i will check for that vaccum line your talking about and thanks..

[93forestpearl]

For tuning you could...
Lean it out before 4,500 RPM. More lean is more heat which is quicker spool. Switching to a higher grade of fuel or E85 or water/meth injection can help you accomplish this.
Pull the timing, once again same issues with detonation unless you do water injection, meth, or run higher grade of fuel. Keep your combustion chamber cooler also helps with detonation. Cermaic coatings assist with keeping heat OUT of your pistons and combustion chamber and help it flow into the exhaust.

Unfortunately, he only has control over fuel, as far as what I understand of the PP6. Lowering the timing advance a little can pay good dividends in the spoolup area. A later spark means more heat in the exhaust as well.

[Kelly]

Dont sell that turbo, you'll regret it. Its not laggy.
I had full boost by 2700 to redline. Seriouslly, REDLINE!

Its baisiclly a GT28RS with a bit larger exhaust housing.
It is ball bearing, I believe the RS means Dual Ball Bearing.


VF39 would be a huge downgrade, so would the 30 and at least a 34 is somewhat respectable. Even the VF22 and 23 were crap in my oponion. And 16g, 18g? When the turbo thats in there is a Garrett GTrs cartrige? Dont bolt in some Mitsu Crap. (like trading Lobster for a freakin Big Mac)

It is internally wastegated.
Dont touch the boost. MAF and injectors were maxed @ 13psi. I was happy with the power. Those injectors wont do anymore than that, but the turbo should do 18psi easilly.

Dont stroke it.
Dont anti lag
For christ's sake dont lean it out!
In fact, dont listen to any of these guys.

Get in touch with Doug, go to his shop, take him some beer, ask him questions that he WILL know the awnsers to, and give him a little pat on the ass for me!

I would HIGHLLY suggest getting someone who knows Subarus to read it on the DYNO ASAP! Theres no telling what the two guys after me have done to it. And 100 bucks on the dyno will be a helluva lot cheaper than new pistons.

PS I heard it already went to PDX once and those asshats just scratched their stupid bald heads and stared at, so I might reccomend Bobby at PRE, or someone else who isn't a complete fuckin asshat.

Thanks.
Kelly

[Kelly]

BTW.

This is what you need to fix the vacum leak.



Coutersey of SLOdrive's buildup thread, page 2.
He goes into good detail about the issue and does quite nice work too!

I used some squishy cork at the time due to a lack of tooling to fab the plate and forgot about till after I sold the car. It was temporary, sorry.

Carry on.

[Mattheww044]

ok. so is there a part number for that? or should i just have my stepdad make me something like that? (hes a welder)

[93forestpearl]

I believe the RS means Dual Ball Bearing.

R means ball bearing. The S is a special designation by Garrett to differentiate it from a similar model.

In fact, dont listen to any of these guys.

I'll agree with not leaning it out without knowing what is going on via proper data logging, but statements like this are rather immature and do very little to help people and a community like this. I you have something to refute, quote and disagree in a professional manner.

[douglas vincent]

93forestpearl/Dan, not sure if you were aware, But this WAS Kellys car, so he has SOME say in who to listen too when he hears stuff that SHOULD NOT be done to the car. He never blew it up, (well there was that one valve incident ), he did run it with a wide band and so forth. So he does know (or has a strong opinion) on what NOT to do.....

I worked on this car a little when the 2nd owner after Kelly had it (the guy who sold it to Mattheww044. There were some issues with it that I diagnosed but were unable to correct at the time (O2 sensor and Knock sensor). I didnt play with the PP6 at all, other than to confirm it was working (it was). I have NO IDEA what the tune was with regards to AFR.

[93forestpearl]

That's totally fine, and I respect that, Doug. I am just asking him to not be rude. A little background information can go a long ways when making bold statements. If he would have explained what you just told me, I would not have taken offense.