Reducing Turbo Lag / Intake Options

[pixel8r]

Hi guys,

This one isn't about what turbo to buy, as turbo lag affects pretty much all turbos, to various degrees.

I'm actually after some fairly general info on things that can be done (hopefully inexpensive!!) to reduce turbo lag or increase low-end power/response.

Some things I have thought of so far are:

* 3" exhaust with good flowing dump pipe - I already have a custom 3" turbo-back exhaust, and it made a HUGE improvement to turbo-lag and response.

Q: Would wrapping it in heat-wrap stuff help at all? particularly the dump pipe off the turbo? Also the stock turbo heat shield had to be removed to fit the exhaust - should I be looking at creating a heat shield to replace it?

* Cold Air Intake - This is the main one I want to investigate. I'm guessing if I can either open up the air intake a bit or make sure the only air entering the intake is cold air, then this should have a positive affect on overall response. Wondering if any heat shielding or heat wrap could be used on intake piping to improve things here as well?

I've heard of people using pvc or flexible aluminium piping running into the airbox, or even multiple cold air intakes into the airbox? This would be fairly cheap to do I imagine...but does it bring results?

Other things to reduce lag are:

*Apexi SITC (super ignition timing computer/converter) - these are hard to find, but can be very effective in reducing lag (i dont have one yet...)

* EBC - apparently a good boost controller can also build boost quicker and hold it better etc. I do have a turbotech-style manual boost controller which works well for boost build-up.

Thats about all I can think of, other than actually replacing the turbo etc. - let me know if you can think of any relatively inexpensive ways of improving the low end for turbo RB cars.

For the record I have a GT30/hybrid (standard R34 exhaust housing I think) fitted by ATS (Adelaide Turbo Services).

Boost is first noticeable at ~2500rpm and full boost is around 4000rpm, although it comes on hard around 3000-3500rpm.

Edited April 29, 2007 by pixel8r

[paulr33]

my top 10 list

1. stand alone ecu

2. tune

3. tune

4. tune

5. tune

6. tune

7. tune

8. exhaust manifold / housing setup

9. good boost controller

10. good cold air instake

[pixel8r]

my top 10 list

1. stand alone ecu

2. tune

3. tune

4. tune

5. tune

6. tune

7. tune

8. exhaust manifold / housing setup

9. good boost controller

10. good cold air instake

As mentioned in my sig, I do have a SAFC, which was tuned by boostworx here in SA.

Please expand on what you mean by good cold air intake...is this as simple as re-routing the intake piping from the front of the airbox?

[BAMR33]

Big side mount intercooler - reduced piping, lower pressure drop.

Pre-turbo water/methanol injection

ex-cam gear

de-cat

tune

[paulr33]

get a stand alone ecu

get a real tune

unless you are auto?

if so get a remap or get safc & sitc and tune tune tune tune

forget the cold air intake as long as you arent sucking in hot hot air it wont help much

also make sure you arent bleeding via a stupid bleed valve and a leaky actuator

ideally do a dyno run with the boost line removed (unlimited boost mode bang bang) and see what the ramp looks like

you may find the bleed valve and actuator are opening early

[pixel8r]

get a stand alone ecu

get a real tune

unless you are auto?

if so get a remap or get safc & sitc and tune tune tune tune

forget the cold air intake as long as you arent sucking in hot hot air it wont help much

also make sure you arent bleeding via a stupid bleed valve and a leaky actuator

ideally do a dyno run with the boost line removed (unlimited boost mode bang bang) and see what the ramp looks like

you may find the bleed valve and actuator are opening early

yeah its auto. a SITC is on the shopping list however...

not using a bleed valve, its a JRD manaul boost controller off ebay - same concept as the turbotech mbc. It restricts pressure to the wastegate, rather than bleeding it off, so therefore building boost quicker and more reliable than a bleed valve. search for $22 boost controller in this forum...was near the top a few days ago...

I really think the SITC is required for the tuning side of things. The SAFC has improved the mid-range a bit but I think lag-gains are mainly achieved with the SITC...

Would the stock snorkel be sucking in hot air? I'd be happy to rig up a CAI if there was going to be a noticeable improvement in intake air temps...

[govich]

I'm actually after some fairly general info on things that can be done (hopefully inexpensive!!) to reduce turbo lag or increase low-end power/response

Properly matched turbo, good cam timing, well designed inlet and exhaust manifolds (not cheap), minimise piping and number of bends, use large radius bends, efficient intercooler, light flywheel/tailshaft, light wheels (etc), good EBC, proper engine management and finish it all with a good tune!

Edited April 29, 2007 by govich

[pixel8r]

So can I gather from the responses that the stock air intake does not pose any restriction?

I was of the understanding (or hoping) that maybe a bigger snorkel or improved intake piping (ie. in front of the airbox) or heat shielding may make a noticeable improvement...

[series2r33]

This is how i made my CAI

As for improvement one can only imagine that its getting alot more cold air directed right at it so its gotta be better

[Risking]

I wouldnt be using those apexi things. To start with they are not very acurate and frankly why would you want to tune something so rough??

Buy yourself something like an emanage etc and tune it properly.

I agree with the cam gear suggestions tunned well they can make respectable gains.

A good EBC is also an excellent idea, however I dont think CAI is really an major player when it comes to lag. Does the turbo really care what temperature the air entering it is?? Yes on a cold night there is a remarkable difference but honestly intake temps on a normal day will not drop that much with a CAI.

[paulr33]

i agree emanage is a good idea get that

let you tune as much as you can

im thinking of gettting an emanage so i can do a faq on it

wouldnt mind it

given pfcs are hard to source now

[Risking]

they are good but for a serious tune you need a knock box or at least know what your doing with ignition timing maps

[pixel8r]

Haven't heard of a single person getting good results from the emanage on an auto stagea. The ones that have been done here in SA have had all sorts of problems including coilpacks packing up.

SAFC's are used by a LOT of people on here and all with great results. Not sure how you can say they are inaccurate when you can run dyno after dyno showing a clear and clean AFR graph. They are set in 500rpm increments and will do a smooth blend between each point. Thats as much accuracy as you need - any more points would not be noticeable in real life anyway. All they do is modify the AFM signal - so no big task, and they handle that very well.

They have limits to how much they can adjust because it will affect ignition timing - but coupled with a SITC they can be tuned VERY well.

It may not be as clever as a full computer but IMHO a full replacement computer will never be as good/nice overall as the stock ECU. It may give more performance and efficiency but as far as all the features programmed into a standard factory ecu, it wont do all the same things. Apparently factory ecu's are a LOT more complex than the aftermarket ones. Take that how you will - I'm more talking about keeping the car as nice to drive for a daily driver as possible.

My car is purring at the moment - runs like a dream.

Was just after a hopefully cheap improvement to turbo spool-up time.

IMO the Apexi SITC is probably the best way for me to do that.

Many people have managed 200+awkw using the SAFC & SITC combo. I'm not that interested in pushing my max power up, more just to optimize lag as much as possible without replacing my turbo...(i'm not at all unhappy with the turbo).

[paulr33]

given you are stuck with the stock ecu i reckon the emanage is your best bet

but you need it installed correctly and a competent tuner for it

there was some early installl issues and frying coilpacks but i think thats all fixed now

[jazza08]

Better actuator and elc boost controller will bring on boost as quickly as it can.

No point in runnin 9psi on a bigger turbo... Find a HKS 1 bar actuator (or generic and make it fit) and just use that, will work well with the bigger turbo, also check to make sure 12 to 1 AFRs are ok on that boost level and its not pinging! Most ppl tune to around 11.5ish to 1 that ive seen on the rb25's.

[InterCooL]

the only thing i think you will really notice to reduce turbo lag will be nitrous or a smaller turbo..

[Pauly33GTS-t]

pixel8r im running same turbo kit as you, identical. Do you know if fitting a different actuator to it is something that we can do? I'm not sure what actuator bill is using on his hybrids, they look new though. could be one provided by garrett?

[Pauly33GTS-t]

Sorry for the doub post, but pixel, I think that it is possible that fitting a proper ECU like an emanage or a PFC would eliminate any lag issues that are easily fixed, and would improve economy and driveability... Instead of tricking the ecu, it will be working with it, or in a PFC case, working with itself. Emanage would be the best bet, I think its problems are all sorted now.

[pixel8r]

Sorry for the doub post, but pixel, I think that it is possible that fitting a proper ECU like an emanage or a PFC would eliminate any lag issues that are easily fixed, and would improve economy and driveability... Instead of tricking the ecu, it will be working with it, or in a PFC case, working with itself. Emanage would be the best bet, I think its problems are all sorted now.

Emanage might be worth looking into later then - wasn't aware of anyone running this successfully in an auto yet...

Also I'm not sure an actuator is what I want to do - IMO this is just doing the same thing as having a good boost controller set to 1bar...

and at the moment I dont have the supporting mods to run any higher than about 12psi (need better fuel pump, injectors?, fuel lines, brakes, SITC - just too expensive right now...).

Dont really wanna make that jump until I can afford it which is several years away...(need to save for a home loan )

[Tangles]

SITC's are worth it mate, with the auto. they do reduce the turbo lag effect, slightly, once tuned. they make a difference.

look youve got a nice safc tune already, grab the sitc ($220usd off ebay) and have it installed and retuned.

figure out what sort of boost you want to run and work around that, telling the tuner to work on response, but surely a minimum of 1bar is called for - its not as if you can always use it in adelaide traffic anyway, but its good to have it when you want it.

currently I have 190rwkw at 14psi dropping to 12psi as the muffler is a huge restriction. welding a highflow muffler on this arvo, hopefully, for $80. then fitting the exhaust cam gear wheel and have a final tune tune tune, up it from 14 to 15 and hopefully it holds steady, and Id expect around that 220rwkw mark utilising a freely flowing exhaust (incl adj cam gear) and intake (using return air feed apexi cooler and a cai with pod using snorkel and radiator air guide) with highflow slide turbo, adj fuel pressure regulator and direct battery-fed large fuel pump, z32 afm, sitc and safc. response will be fantastic without doubt.

with the 190rwkw tune she is nice and docile in traffic never building boost if you dont want it (saving fuel), or rips thru to 14psi with a niiice surge in power/torque. a true street sleeper. with the slight increase in boost, highflow Kakimoto muffler and the exhaust cam gear wheel I have no doubt that the Stagea will be a true pleasure to drive, and that turbo lag wont be a problem.

SITC ftw!!11!!!111!!!