Jim in Tucson

iTrader: (3)

I've been following with great interest razorlab's thread on Well set-up ECU-controlled boost. I've been most impressed with the 24.5psi spike on 91 octane. Awesome!!!

I realize this was on a IX and I have an VIII, but where is the weak sauce in my set-up?

My mods are:
K&N drop-in
Hallman MBC (21psi spike tapering to 18psi)
IX bypass valve
Helix down pipe
Helix test pipe
Greddy EVO2 cat-back (modified)
HKS 264/264 cams
Nisei LICP
Walbro 255Lph fuel pump
IX turbo
PPI ported ex manifold
SS O2 housing
318whp/311trq on MD (prior to Mellon Tune and FMIC)
Mellon Tuned
ETS 3” FMIC

Any suggestions???

Thanks,
Jim

tephra

iTrader: (6)

Have you tried running more boost?

lemmonhead

i only have a full 3" TBE. I had trouble holding 25psi on 92 gas(had 2-3 counts of knock). I had to retard timing way to much for my liking to get rid of knock, BUT i also had a very aggresive MIVEC map. In the end I reduced my MIVEC in the 240-300 load range and was able to increase my timing back and hold 25 psi, 20-21psi redline.
I say fiddle with the MIVEC a bit keeping all else same and see if it helps.

ChuckP

iTrader: (7)

Have Razorlab tune you car?

But seriously, all evos are different. And im pretty sure he mentioned this was a "freak."

RazorLab

iTrader: (8)

Evo 9's are much much much more tolerant to boost than Evo 8's from my experience. I contribute it to the head design and mivec.

Yours looks like a pretty solid setup. If you want to hold more boost up top, look towards ecu-controlled boost and a upgraded actuator.

Wicked E

iTrader: (26)

The advantage is having the IX block with MIVEC...

tabio42

iTrader: (15)

It might also be falsely showing knock because the knock filters get more sensitive as the boost goes up. Like picking up engine noise.

badhabit90

iTrader: (13)

uhhh...reading comprehension is good here...hehehe

codgi

iTrader: (22)

His is an VIII so he has no MIVEC .

JohnBradley

iTrader: (30)

Timing is irrelevant to a point. After reading what Mark Shead had to say in the Magnus intake manifold thread (before it disappeared), I decided to go out and try running as much boost on pump without knock as possible. I also log WHP as a function of load so I can quantify changes.

Best with 25-22psi and timing ranging from 2-3* to 14* by redline was 375whp

Best with 28.9 tapering to 25 and timing going from 0* to 9* was 405whp. I dont have an EGT probe, but there was also no knock. I have one log from testing running that level of boost but there was some knock but not till it tapered to almost 23 (that was just a simple miscalculation).

cliffs- drop timing, keep AFR's where you want them, raise boost...profit?

tephra

iTrader: (6)

so boost is better than timing?

so the golden question, how much boost is safe for a street car (23 to 20?) and how much is safe for a track car (19flat?)

DrivinMissDaisy

iTrader: (1)

My car boost spikes at 25psi at 3.5k and then tappers down to 19 at redline. I have no knock. I even raised timing to *5 after spool to 11 at redline. I run 91 **** water.

AFR's are 12+ during spool and drops to 11.1 by redline.

EFIxMR

iTrader: (10)

hardcore

RazorLab

iTrader: (8)

You might be interested in this post (which references the 1st post in the same thread):

https://www.evolutionm.net/forums/sh...88&postcount=6

JohnBradley

iTrader: (30)

Bryan I had seen that thread and I decided that I am going to go back to ECU based boost control. I havent had very good luck with the factory BCS and the Green, the Hallman I am using now was touchy till I rebuilt it, but that boost curve is exactly what I would like to be able to do.

One more project to add to the list of things I need to do to my own car

COP,
Bigger Cams,
Meth,
MAFT PRO,
3 Port,
etc.

I apologise for the threadjack, but it seemed relevant to discuss boost vs timing again.