fixing lag? - Page 3 - Perth-WRX.com

Kato · #21 28-09-2010, 01:57 PM

Quote:

Originally Posted by fatboy

I agree, i am starting to wonder if there is something amiss with the tune, compared to what i am seeing with other cars with similar mods i am starting to think that it might not be quite right!

I'd ask them what your injector duty cycles are.

From what I have read 260+hp is 90+% on the IDC. This may be the limiting factor.

Also have you upgraded the fuel pump?

jesstamic · #22 28-09-2010, 01:58 PM

I dont believe its the tune, I think you need alot more supporting mods for the engine to be compatible with that turbo. Most of the power with it is in the high rpm and currently it cant support it which is why its laggy.

fatboy · #23 28-09-2010, 02:17 PM

Quote:

Originally Posted by jesstamic

I dont believe its the tune, I think you need alot more supporting mods for the engine to be compatible with that turbo. Most of the power with it is in the high rpm and currently it cant support it which is why its laggy.

Yeah but what i have done is fairly common on an MY08 and most dyno graphs i am seeing are more responsive down low!

I spoke to Mark at GT Pumps and he reckons i am at least 500-750 revs higher up the rev range than most customers with similar setups!

he mentioned to play with the avcs and only fucus on what is going on below 4k as above that seems pretty normal

Quote:

Originally Posted by Kato

Also have you upgraded the fuel pump?

No i havn't, but there is an issue with the 08 that it kills walboro pumps after only a couple of months (or so i am told)

RUSSGT · #24 28-09-2010, 02:36 PM

Quote:

Originally Posted by BALISTC

It's physics.

Tube & Fin cores have better external aerodynamics than a bar and plate core, the external air flows around the tubes better. The internal air cools better, which means its denser.. which means less lag.

That being said, bar and plate suffers from heat soak less, due to its heavier construction, and internal surface area is larger which generally means less pressure drop through the core..

Its splitting hairs in a street or mild (>400WHP) application, but just FYI, the 08 STi TMIC has a massive surface (9,600 fins just on the surface layers on the front and back, not including the internal fin area), is cheap, and is worth giving a shot to see if it works better..

Either core needs a very good water spray setup to maximise the efficiency of it.

I'll be trying this shortly and I'm hoping for some decent results

Yeah i too cant see any gains to be had from switching.

Quote:

Originally Posted by Kato

Still haven't seen proof that the PW TMIC is better than the STi TMIC too. Which was promised when they were first made.

Tbh, it makes sweet f.all difference in the applications most people are talking about. I'd be willing to bet both will act the same, which is why there is no 'proof' that one is better than the other.

I just wouldnt stuff around changing the TMIC for maybe 2rpm difference.

Also which is which with the graph you posted?

Kato · #25 28-09-2010, 02:43 PM

Quote:

Originally Posted by RUSSGT

Yeah i too cant see any gains to be had from switching.

I just wouldnt stuff around changing the TMIC for maybe 2rpm difference.

Also which is which with the graph you posted?

No, if you have the PW, no point changing.

Red line is a GD spec TMIC, lower blue line is PW.

fatboy · #26 28-09-2010, 03:09 PM

here is a graph of the same car with exactly the same mods but tuned with ECUTEK (and running 15psi)

This looks a lot more agreeable to me than what i have?

Below for easy comparison

monkeee · #27 28-09-2010, 10:04 PM

What about a VF34/P20 + Intake + Equal length headers. Smaller turbo but it would be more responsive on a 2.5L and you wouldn't be at a loss (at least torque wise).

All in the name of a useable power band.

Just throwing it out there as another idea

jEstEr? · #28 29-09-2010, 01:53 AM

It will be the Quad AVCS. My Quad AVCS motor is also a laggy POS. I think Sean just needs more time with them.

EJ20Y, Kando equal length, VF48, V10STI TopMount. Thin line is TD04 tune

type25 · #29 29-09-2010, 08:06 AM

Big fuel pump+bigger injectors+E85+more aggressive tune=moving the graph to the left (the result you're after)

207 de · #30 29-09-2010, 02:02 PM

Joe and John are right, with that turbo on a 2.5 you should be seeing full boost before 3500rpm.

Tuning, fuel etc. Both a hell of a -lot cheaper and simpler to sort out than cams etc.

If you really want to spend some cash, get some proven headers (coated/wrapped obviously) and re-tune.

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