Okay, so first off, I am not familiar with preludes at all. My buddy has a 4th gen H22 lude that he just got done turbo charging. There are a few problems though. The car ran perfect before the he installed the turbo. His setup is DSM 450s, Walbro pump, and Hondata running on a P72 ecu I believe(whatever the GSR ecu is). Okay, so the first problem is the car doesn't want to idle for ****. He has had the basemap burned on the hondata, but even a base map cant be this bad I would think(I run hondata on my hatch, my base map was NO WHERE CLOSE to being that bad). He T'ed off his FPR line for the wastegate and the boost guage, one thing that is interesting is that when you pull the FPR line, the idle smooths out and the idle a/f leans out to 19:1. When the FPR line is attached to the FPR, the a/f riches to 17:1 and th car can barely idle. He installed an AEM fuel rail when he put in the DSM 450s, is there any problems or install errors I can look for that might be common with that rail? Another thing, he threw a code last night saying the primary 02 is going bad. We scanned it, cleared it, and it hasn't thrown it since???(he has been driving the car around). They hooked up an a/f guage, I am not sure which wire they are supposed to hit, because if a/f guage reads lean the whole time....like it barely even works. Could you guys please tell me what color wire the a/f gauge taps into on the 02 sensor? Now, last but not least, and I know this is a crappy pic, but he has what seems to be some sort of vaccum line not hooked up and he doesn't know where it goes. I had no clue as a Prelude is about as similar to my car as a Bronco is to a Lotus. I had my buddy snap a pic, we thought it might be some sort of vaccum pump or something. It is outlined here in red and I am holding up the line. I understand it is hard to see, but if you guys could just tell me what that black box does and where those vaccum lines hook up that would be awesome. Thanks for any help guys, lord knows he needs it.

 

That black box ran to an air box that was located under the passenger side front fender. In order to run the intercooler piping he had to remove the air box from the fender well. On my car i took that vaccum line and the box it connects to completely out of the loop.

It is no longer necessary. Just make sure that it is completely out of the flow of all of the rest of your vaccum lines and that part will be good.

As far as the O2 sensor goes, i can't remember which wire we tapped, but i can find out.

 

DSM 450s, according to what I have read many times, do not work with Hondata.

 

ya it also sounds like you need to separate some of your vacuum lines do different sources on my turbo lude it made it want to stall too, two together are ok, get one from the brake booster or something

 

Well, I am running DSM450s on my hondata and have no problem at all. I appreciate all the help fellas....anything else you guys would like to comment on or would guess as to why the car is having such problems idleing would be awesome.

 

you dont need that black box with the vacuum line coming from it.. it control the valve thats apart of the resonator

 

are DSM injectors saturated or Peak&hold?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by sharkcohen &raquo;</TD></TR><TR><TD CLASS="quote">DSM 450s, according to what I have read many times, do not work with Hondata.</TD></TR></TABLE>

Shark, isn't that to do with DSM injectors being peak and hold? most people with hondata (OBD1 civics) use saturated injectors (no resistor box) where preludes come with peak/hold injectors and resistor box stock? (somebody correct me if i got this backwards..) Anybody have some firsthand info on this? I just can't seem to think of any reason why DSM injectors wouldn't work?

 

I believe the base map is your problem.

Hondata provided me with a base map that started my car, but it would idle like **** and barely drive. It ran excessively lean with WAY too much timing. I drove it for maybe 1/10th of a mile then I decided to promptly remove it until I was at the dyno. I recommend removing the injectors and hondata and running the stock ecu and injectors until the car is tuned.

Civics/Integra's that run the DSM injectors need to use a resistor pack. 92-96 Preludes come with resistor packs, so you are fine.



Hopefully that will help you out. That is a picture from my manual, it is not intended for any type of illegal copying or reproduction.

 

The thing you have circled is part of the old intake system it can all be removed it's useless.


Am I the only one that looks at that piping to the TB and goes WTF? What is that..2"? It looks like the piping is going on the inside of the throttle body!

The reason your car idles like **** is that you're not giving the engine any air! You Need some realy piping in there...2.75" diamter at a minimum...holy schnikes!

 

There used to be a page on the Hondata website where Doug stated that Hondata doesn't recommend DSM injectors for use with their product, but it appears to have been taken down.

Remembering reading a bit about this, I did a small search regarding the subject, but after reading the various threads I found it seems that everyone had opinions and few had any solid answers Also, links in these threads to the Hondata page discussing this came up "page not found".

Anyway, ditch the "a/f gauge" and get a wideband. a/f gauges that run off the narrowband O2 sensor are worthless.

It's probably not a good idea to use a line for the fpr that two other devices are sourcing for use. Try a dedicated vacuum line for the fpr.

I agree with Precision, the basemap is the most likely culprit.

 

2.75" intercooler piping is overkill unless you are running an to4S trim turbo with huge a/r trims. 2" is not enough though... a good happy medium is 2.25" intercooler piping.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by PrecisionH23a &raquo;</TD></TR><TR><TD CLASS="quote">2.75" intercooler piping is overkill unless you are running an to4S trim turbo with huge a/r trims. 2" is not enough though... a good happy medium is 2.25" intercooler piping.</TD></TR></TABLE>

maybe I'm confused because all motor we run 3" intakes...what's up with that?

 

3" is only needed above 750+whp for turbocharged applications.

The piping is smaller because it helps to increase spool up times since you are forcing more air through it. The larger the piping the larger amount of pressure drop you can get.

For regular set-ups, 2.25" is all you need, very typical for the E housings (60ar). If you are running a S trim housing (70a/r), then a 2.5" i/c piping is great to use. Not a lot of people run 2.75" piping unless they are running a gigantic turbo and putting out 600+whp.

I am staying with 2.25" I/C piping on my set-up and will be shooting for 500whp this time. Typically you match your IC piping to your compressor outlet of your turbo. I would get into the whole thermodynamics of it but I'm busy studying for a test.

 

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

maybe I'm confused because all motor we run 3" intakes...what's up with that?</TD></TR></TABLE>

a few psi?

 

learn something new everyday

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by sharkcohen &raquo;</TD></TR><TR><TD CLASS="quote"> Try a dedicated vacuum line for the fpr.

</TD></TR></TABLE>

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by PrecisionH23a &raquo;</TD></TR><TR><TD CLASS="quote">


Hopefully that will help you out. That is a picture from my manual, it is not intended for any type of illegal copying or reproduction.</TD></TR></TABLE>

justa suggestion, couldn't he use the vacumm line used for the intake resonator (8) for the wastegate and boost guage. then he has a dedicated line for the fpr.

 

Awesome, Awesome, Awesome fellas...thanks for the replies. Any word on what color line to hit on the 02 sensor for the a/f guage?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 1.8t &raquo;</TD></TR><TR><TD CLASS="quote">Awesome, Awesome, Awesome fellas...thanks for the replies. Any word on what color line to hit on the 02 sensor for the a/f guage?</TD></TR></TABLE>
black

 

Hmn I have always had oppinions on this as well. Say you do have a nice largely sized turbo and at least a 3" piping. Wouldnt it be just as beneficial to up the boost to compensate for any pressure drop you may get with larger piping...

Again this is assuming you are going with a large turbo, high compression (maybe starting @ 10:1) and 3' piping all around including exhaust..

Tell me your thoughts.. *sorry to post jack*

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 1.8t &raquo;</TD></TR><TR><TD CLASS="quote">Awesome, Awesome, Awesome fellas...thanks for the replies. Any word on what color line to hit on the 02 sensor for the a/f guage?</TD></TR></TABLE>

White, if you tap it near the ECU.

 

i have a question too...i found a turbo 4th gen lude and the intercooler seems to be about 6 inches from the ground...just didnt look right

i wouldnt know i actually havent seen a turbo 4th gen in person

 

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


white on a 4th gen

and if your a/f gage reads lean, then you pull the fpr line and it runs better...your gage is probly right, since pulling the line increase fuel pressure...i always leave this line off, so we have a consistant fuel pressure for tuning. if you leave it on, it changes w/throttle postion and rpms....great for stock setup, shitty for spacific tuning

 

Well, here is the interesting thing. Wouldn't pulling the FPR line richen the car up since fuel pressure increases?? When we pull the FPR line, the idle leans out as apposed to when the FPR line is attached. Any comments?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 1.8t &raquo;</TD></TR><TR><TD CLASS="quote">Well, here is the interesting thing. Wouldn't pulling the FPR line richen the car up since fuel pressure increases?? When we pull the FPR line, the idle leans out as apposed to when the FPR line is attached. Any comments?</TD></TR></TABLE>

Yes; if you had read Precision's comment above, you would see what his experience with base maps was like.