Hi everyone,

My stock 5th gen prelude (with Injen Short Ram) had 165 whp and 142 tq. Later on, I installed the Vibrant header and Brullen exhaust. The power now is 163 whp, 130 tq.

I know the main reason for this is my AF ratio. Today, my friend and I, found out how bad this really is.

I think I was in third gear, at around 2500 rpms, and I floored it (the numbers are accurate the best I can remember):
-2500 rpms - 12.9 <- air fuel
-as the rpms got higher the AF got worse
-before vtec - 12.5
-at 5250 rpms - 11.9
-around 6500 rpms - 11.5
-and finally at 7100 or so - 11.1

Can someone "technical" explain how this is possible? It seemed all of sudden because when I went earlier on dyno (April/May) I was stock and I was not running that rich, but after those bolt-ons, my lude was smoking like a chimney, better flow i guess.

Now, when I started all of this, I just wanted my car to sound better, I was not concerned with HP numbers, but now I am kind of forced to go step further and tune it.
I am asking for some suggestions on what to do next? Few extra ponies would not hurt.

Somehow I am leaning towards p28 + hondata s200, and would like to know some negatives in doing so.

Thank you.


Modified by SilverBullet_01 at 11:54 PM 8/12/2008


Modified by SilverBullet_01 at 12:00 AM 8/13/2008

 

Were you on the same dyno both times? And how was the weather outside?

 

i wouldn't waste the $300 (hondata + ecu) for a few extra ponies, then you have to tune the thing (which i'm assuming you are trying to do yourself or have a friend with some knowledge helping you out.....probably just a weather change is enough to vary the results on the dyno.

Unless you did both tests on the same day to compare?

 

I think a p28 and Hondata is a good idea as it seems that people never stop upgrading. Then at some point you really do need something like Hondata. IMO, better to have it sooner than later.

 

thanks for the replies guys

tests were done on different days, but the weather outside was similar

first time i went i was stock - and there was less smoke, the last time i went after installing header and exhaust - the car was spitting out like crazy - that is why i did the AF test and found out i was running too rich

the 2 whp less do not bother me that much, but why did i lose 12 tq?

as for the tuning options, many people are pushing me to "do it right" and go with a diff ecu + chip

i know it is more than let's say a vafc - but if it is better and more beneficial for my setup, i will pay the extra $

i would also like to hear if anyone has some negative comments about going diff ecu + hondata

 

Buy a used VAFC and have it tuned.....your setup is choking on fuel right now.
This is a perfect example of why people need to tune....You just spent $1k(?) on mods and hurt your setup.....So many people do this same thing, youre not alone.
My negative comment about Hondata would be its probably more than you need right now. You can buy a cheap S100/200 but they suck to tune with the chip burning and such....my 5yo niece could tune a VAFC.......on my friends ~180whp setup after hours of fussing with his S200 it netted like 3whp/0tq over the best VAFC run he had.
I made almost 200whp with nothing more than a VAFC....and not to mention I can dial them in SUPER FAST with less than 10 passes.
People can say what they want about VAFCs but the proof is in the pudding....its not uncommom to gain 5-7-10whp peak and 10-15-20whp in the mid.....If you made 165whp stock, it wouldn't be uncommom to even get 175whp tuned as I have seen numerous times......Sounds like a good reading dyno!
VAFC1=$100
1hr Tuning=$100
The look on your face when you hit VTEC for the 1st time on your way home???
PRICELESS!!!
Driving a tuned car(even with only a vafc) just buries driving an untuned car.....

 

was this a sniffer wideband that gets placed into the rear of the exhaust? if so, its possible that the filter is clogged in the system and is giving out the wrong readings. If there was a car on there that day that was running really rich, it can clog it to the point to where the breather system needs to be taken apart and cleaned. Not likely the answer, but its possible.

also, changing your plugs could also fix the problem. If they are old then the spark is possibly not igniting the whole fuel/air mixture leaving unburnt fuel in the combustion chamber which shows up as richer on the wideband.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by NirVTEC &raquo;</TD></TR><TR><TD CLASS="quote">Buy a used VAFC and have it tuned.....your setup is choking on fuel right now.
This is a perfect example of why people need to tune....You just spent $1k(?) on mods and hurt your setup.....So many people do this same thing, youre not alone.
My negative comment about Hondata would be its probably more than you need right now. You can buy a cheap S100/200 but they suck to tune with the chip burning and such....my 5yo niece could tune a VAFC.......on my friends ~180whp setup after hours of fussing with his S200 it netted like 3whp/0tq over the best VAFC run he had.
I made almost 200whp with nothing more than a VAFC....and not to mention I can dial them in SUPER FAST with less than 10 passes.
People can say what they want about VAFCs but the proof is in the pudding....its not uncommom to gain 5-7-10whp peak and 10-15-20whp in the mid.....If you made 165whp stock, it wouldn't be uncommom to even get 175whp tuned as I have seen numerous times......Sounds like a good reading dyno!
VAFC1=$100
1hr Tuning=$100
The look on your face when you hit VTEC for the 1st time on your way home???
PRICELESS!!!
Driving a tuned car(even with only a vafc) just buries driving an untuned car.....</TD></TR></TABLE>

Are you speaking about a stock prelude or with mild mods here?

 

i think he is speaking about mild setup as he stated i spent 1k on the mods, but hurt the performance

to 98vtec:

the sensor was just before the cat so it should be precise

since i bought the car i haven't changed the plugs (i made about 30 000 kms), they probably are the mess. i ordered a set of Denso Iridiums 2 days ago

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by CAN97SH &raquo;</TD></TR><TR><TD CLASS="quote">

Are you speaking about a stock prelude or with mild mods here?</TD></TR></TABLE>
Bolt ons.....
Usually what I saw on my old dyno was a stock Prelude making low 160's and a little more with i/h/e and we were able to get 173-178whp from a i/h/e H22 tuned on vafc.....It just depended on the EXACT brand of header/exhaust.

I don't think the sensor was clogged, it just seems like his car has too much fuel. I know i/h/e make power.....The Vibrant header and Greddy SP2 made 15whp/9tq after tuning with a VAFC.

 

how about p28 and crome?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SilverBullet_01 &raquo;</TD></TR><TR><TD CLASS="quote">how about p28 and crome?</TD></TR></TABLE>

More money and trickier to tune than a vafc.....more Dyno time.
Its just not needed for a mild setup....and besides Crome is not good in my book.

 

wouldnt say more dyno time but it does require a little more intiution. If you cant get a simple motor like this tuned in an hour then i would be a little worried.

 

im going with p28 + crome

good luck to me

 

look into eCtune please

 

there is no ECtuners around here

also, if i get the p28 OBD1 ECU and crome, how do i check the engine codes and how to get rid of them?

thanks