Rikter

Hey folks,

Just need some quick advice here as I've gone through 3 engines and I don't want to blow this one too.

Had a LSVtec running 9:1 compression with a T3 Super 60 turbo. It was dyno tuned conservitely and all was well except thanks to poor coolant resevoir placement and catchcan placement and a blown o-ring I ended up blowing the motor. Due to the damage on the pistons there is a guess that overtime small amounts of knock + the other problems killed the engine. Normal driving A/F's were around 14-15 while in boost I saw 11s. Running 10psi

New engine, different pistons. Still around 9:1 compression but now a full 3 inch dp and exhaust, t3/t4b turbo, external dump from teh wastegate. I'm still on the old tune on my ecu chip (chrome) and now at 3psi max to let the engine break in. Plus I want a J&S safeguard before I go for 18psi. My current problem is that my a/f's are reading 7.4 normal driving and about the same in boost. Definitely running pig rich and my gas mileage is suffering for it. My question is... am I doing damage to my motor running that rich?

-Rik

zman

11:1 at 10psi is a little rich....depends what it is though....high 11's is ok, but like low 11's would be a little excessive at those boost levels.

Rikter

Edit: when I said 11's I meant 11 on the a/f ratio, not psi.

-Rik

Rikter

bump

zman

how far into the 11's were you at 10psi?

how rich were you in the rest of the fuel map? I'd be more concerned about partial throttle/cruise AFR's than what you are in boost.
I don't know how much you're trying to smash on a new engine.
Dipping into the 11's at 3psi would be INSANELY rich, i mean, up to about 5psi i'd never tune a car to run past 12:1 (if that rich).

adseguy

even low elevens isn't "BAD" for the engine you are just wasting gas and fouling plugs, but nothing more. Maybe you shouldn't tune it.....

tuning AF's is just like a quarter of the equation. Timing is MUCH more important and what about tip-in fueling, what about IAT correction (maybe the weather killed your engines). Sounds like you need to learn a little more this time around

Rikter

I think everyone is missing otu on what I'm tryig to say.

I had the car PROFESSIONALLY DYNO TUNED the first time around. Everything was bang on but the P28 ECU does not register knock and from what we could tell from the damage done the first time around is that small amounts of knock over time killed the engine.

What I'm concerned about right now is whether or not an a/f of 7.4 in and out of boost (max 3psi) is doing any damage at all since it is incredibly rich. I will get the car tuned again once I put the J&S safeguard in and at that point I'll increase the PSI up to 18 or so. Reliably and again tuned on the dyno.

Just looking to find out if 7.4 in and out of boost is doing any damage by running so rich. Fouled plugs are wasting gas isin't a concern but if it's more than that I'd like to know so I'd stop driving the car completely.
-Rik

VspecSiR

Isn't 12:1 AFR @ 10psi the same as 12:1 @ 7psi??? I mean, not in terms of volume, but shouldn't the ratio be the same reguardless how much boost you are running.

rorik

wow..I didn't think an engine would even run on a ratio of 7.4:1.
Talk about washing the oil for the rings right out of the cylinder.. I wonder how long the engine would last..10k, 20k miles?

alpha

Get a new sensor for the wideband. It isnt reading correctly

sc4dr

Is the car bogging, or acting funny? That is rediculosly rich. From your description it doesn't sound like you changed enough to have that much of a difference in afr's.

arc_55

Running rich is not only bad for the plugs and just unneccassary fuel, but your oil will get contaminated at an earlier milage then if you were bang on with you A/f ratios. Gasoline or excessive vapour can break down the oil, which can cause issues for engine internals. Just a thought but next time you change the oil tell me if you smell any gasoline. If you do you will probably notice a difference in oil vicosity.

SOHC_MShue

like others said i doubt what you changed caused you to run rich like that...and if it was running that rich you'd have a considerable amount of trouble idling and driving the car. Sounds like a bad wideband.

rorik

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by alpha &raquo;</TD></TR><TR><TD CLASS="quote">Get a new sensor for the wideband. It isnt reading correctly</TD></TR></TABLE>
After reading the first post again, I agree with this hypothesis..

igo4bmx

what wideband are u using? some can't even read lower than 10...

arc_55

yes i would be interested in knowing what wide band you have aswell.