Ok, I'm just in the final stages of preparation for my 1993 JDM H22 Prelude build with the following parts:

Skunk2 Stage 2 Pro Cams & valvetrain
Skunk2 Cam Gears
Skunk2 SS High Compression Valves
Prelude Type-S Pistons & Rods
P&P Head + light skim to knock up compression
Ported & port matched IM
68mm TB
ARP Bolts
I/H/E
Lightweight Flywheel
Sard FPR
Hondata S300

I am hoping to achieve in the region of 250bhp from the build.
Now I was told that I would be able to use the stock OBD1 345cc fuel injectors without problems, but I just need to be sure before the build starts. Now looking on this calculation guide, when I input the estimated bhp (250), # of injectors (4), B.S.F.C. (0.5) and the max duty cycle (85%), it's saying that I need injectors with a 386cc rating
I know that I can use the FPR to knock the pressure up and compensate slightly, but I'd really appreciate some advice whether I'm going to be ok using the stock injectors or if I need to upgrade

Thanks in advance.

 

I've looked into this a bit more, and have found that the 450cc injectors off a 1G Eclipse/Talon Turbo (manual) will fit Honda's, and they are also OBD1 Peak & Hold type

With running at 450cc, the injector duty cycle would be a healthy 72.9%, but has anyone used these successfully on a Prelude before??

 

you have a very nice set up going for you. why not just throw out some more for some aftermarket injectors?

 

Thanks for the repy.

Well I honestly don't mind getting aftermarket injectors like RC's etc if there's an advantage to them, but are there any issues with using the DSM injectors off the Talon instead??
If not, then as long as I get a good quality set I'm tempted to go for them.

Also, bearing in mind I need a minimum of 386cc injectors according to the calculation, on the RC website the sizes for the peak & hold injectors goes up 320cc, 370cc then 550cc. I'm not sure if the 550cc would be to big, but the 450cc's DSM ones seem a good size for the requirement.

 

i'm doing a similar build and I was looking into the DSM injectors as well.

You could also get by with the 370CC injectors, with a FPR, but the DSM injectors will most ilkley be cheaper and will be of equal or better quality.

 

Heres some help. A fully built B16 with Crower Stage 3s and 11.5:1 CR maxed out my 310cc injectors using uberdata.

 

im running the DSM 450cc injectors just get them cleaned and stuff by RC they do it very cheap

 

440, 450 cc DSM injectors would be the next jump...I would say 550cc be too big...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EKHWhat &raquo;</TD></TR><TR><TD CLASS="quote">i'm doing a similar build and I was looking into the DSM injectors as well.

You could also get by with the 370CC injectors, with a FPR, but the DSM injectors will most ilkley be cheaper and will be of equal or better quality.</TD></TR></TABLE>

I've had a word with my Tuner, and he's said virtually the exact same thing. He could up the fuel pressure on a set of 370cc injectors with the FPR, but a set of DSM injectors will likely be cheaper and just as good quality.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ESP-net &raquo;</TD></TR><TR><TD CLASS="quote">440, 450 cc DSM injectors would be the next jump...I would say 550cc be too big...</TD></TR></TABLE>

so what goes wrong when you run an injector that's too big?

 

i am also building a h22 similar to yours minus type-s pistons and i am upgrading my injectors to some rc 440's, i asked a few guys i know and thats what they recommended, also a bigger fuel pump

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by beaneg6 &raquo;</TD></TR><TR><TD CLASS="quote">i am also building a h22 similar to yours minus type-s pistons and i am upgrading my injectors to some rc 440's, i asked a few guys i know and thats what they recommended, also a bigger fuel pump </TD></TR></TABLE>

Now with previously researching through the archives on here, I was lead to believe that the stock H22 fuel pump was good for well over 250whp, so wouldn't need to be replaced with the setup I'm going with

Can anyone please confirm this either way?

 

I can't comment about the fuel pump, we put a walbro in john's car....

But, there is no pitfall to using injectors that are a little on the big side, they are simply more expensive.....get some 550cc, thats what john has in his engine

DSM injectors suck, they don't work right with honda ecus....partial throttle they suck....

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by bb4ever &raquo;</TD></TR><TR><TD CLASS="quote">I can't comment about the fuel pump, we put a walbro in john's car....

But, there is no pitfall to using injectors that are a little on the big side, they are simply more expensive.....get some 550cc, thats what john has in his engine

DSM injectors suck, they don't work right with honda ecus....partial throttle they suck....</TD></TR></TABLE>

I've heard that running an injector thats too large i.e. low duty cycle results in a spray pattern thats less than ideal. Sounds like it dribbles instead of mists. Is there any truth to this, anyone know. I can't find any info on here at all about this.

 

well, i am unsure about lude fuel pumps and civic fuel pumps, i have a 93 cx hatch and got my walbro for cheap, so i changed it out

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by bb4ever &raquo;</TD></TR><TR><TD CLASS="quote">
DSM injectors suck, they don't work right with honda ecus....partial throttle they suck....</TD></TR></TABLE>

Have you personally had bad experiences with the DSM injectors in the past? From reading through loads of posts in the archives on them, everyone who's used them seems to be pretty happy with them TBH.
IIRC, the main difference with them and the RC's is a slightly different spray pattern, with the DSM's being more of a mist spray pattern, compared to the stock injector which is more of a jet spray onto the back of the intake valve. Some people say this makes them better than stock, some say worse....

 

If the injector is working correctly, low duty cycle means it is open for a short time, it should still spray nicely.

I have heard from reputable tuners that DSM injectors suck....thats why I say that.