Injectors plz help

[teamfx]

I been trying to get in touch w/ jim but he isnt around tonight..i have the chance to get rc 370 injectors tonight for cheap...they are for a prelude but tI guess they can be modified to fit a GSR....are the 370's too big or will they be ok with a cartech...someone please help quick..thanks

[Marc]

Rjaffey,

You will be able to run a larger injector with fewer problems since you are running Venom injectors which are pintle type. It's a better injector especially for street use.

BTW, how does the flow testing vary from OEM vs. RC/Venom?


Marc

[94Integra]

How does one go about lowering NA fuel pressures beside the fuel bypass at OE regulator trick. (by zip??)
Would a B&M & cartech allow for lower pressures? I have a B&M with the JR regulator but can only lower pressures to 44psi at idle.

[JRCivic]

The restriction that limits you to minimum pressures of 44 psi is the orifice inside your OE fuel regulator outlet... it is too small to handle the VOLUME of fuel being pumped at lower pressures.
There are TWO fixes: First, the fuel bypass (Rafe's design by the way), or buy one of the new AEM OE style regulators with the larger orifice. This allows more fuel flow, and pressures can be lowered substantially at idle.

Lastly, you can try the elimination of the OE regulator all together by simply tapping the JR adapter plate's center hole to 1/8" NPT and screw a hose barb down on it - then run it directly to the JR FMU. This fixes the fuel enrichment point in vaccuum (meaning it no longer is adjustable), so detonation may result during throttle tip-in or mid-range part throttle acceleration.

Good luck.
Jim


------------------



'93 Civic Si H/B with B18C1, JRSC @ 8psi
Best 1320: 12.68 at 110 mph

[JRCivic]

BTW, sorry I am late. I was busy putting the finishing touches on a Frankenstein Hybrid Civic...

Those injectors are a bit too big there little buddy.

------------------



'93 Civic Si H/B with B18C1, JRSC @ 8psi
Best 1320: 12.68 at 110 mph

[Holden]

teamfx:

For 8-12psi boost, the Venom 320's are ideal. RC 310's will work for 8psi, possibly with poorer fuel economy, but the disc (RC) injectors won't put up with higher fuel pressures like the pintle (Venom) injectors will. This limits their ultimate capabilities.

With your built engine, I doubt you'll stay at 8psi for long. Avoid temptation (all those used RC injectors for sale cheap on PartsTrader and so forth) and hold out for the Venom 320's.

Greg

[12SecGSR]

if you get a VAFC or something like that, they will work fine, that is what I use with my 370s'

[rjaffey]

Marc,

Venom and RC flow rate their injectors at what amounts to 100% duty cycle, or wide open. Venom uses 40psi reference pressure and RC uses 43psi. How OE measures is a toss up. The 240 figure sounds like 90% duty cycle. How did I find this out? I pressed RC and Python for flow ratings of OE injectors and they were very vague about it. After I bought Venom 280s I discovered that they hardly flowed any more than OE, I got more info from Python. They told me that OE injectors rated the same way the 280s were flow in the 265 range (give or take a few).

As RC rates theirs at 43psi vs Venom's 40psi reference pressure, RCs advertised flow rates will be between 3 and 4% higher for injectors that flow the same under the same test conditions.

Jim,

A fuel bypass alternative which I've heard is being used with success is to drill a .025" hole directly inside the OE regulator, through the intererior wall as viewed through the regulator's inlet when it's off the car. This is a smaller hole than what I wound up using, but it's highly dependant on the fuel pump's pressure as a function of volume. Different types of pumps will likely require different size bypasses for optimum performance. This fix is also not as easily adjustable as using a replaceable jet.

Greg,

I think the RCs will handle higher pressures better than the Venoms (or OEs).

[Holden]

As far as which style injector, pintle vs. disc, handles higher pressures better, I was going by the section of the "Honda Builders Handbook" written by Russ Collins.

He said something like (I don't have the book at hand): "Disc style injectors don't work well over 80psi" and "Pintle injectors withstand higher pressures the disc injectors".

I'll look up the exact quotes tonight.

Greg

[Marc]

370cc injectors are far too large for a Honda with a stock ECU. Anything larger than 310cc(which IMO is still too large) will require some form of engine management. Hondas are designed to run 240cc injectors and without altering the engine management you'll be running in circles trying to solve your problems.

Marc