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Discussion Starter #1
The first time I tuned my car I had 174whp at 8500.
The dyno shop told my that my injectors was max out and that I
needed bigger injectors. They told me get rc310 injectors, which I did. So my next dyno run was unbeliveable. I lost about 23whp.
So now they are telling me, that one of my clyinders is not at it's right compression. So since the injectors are the only thing that
I change since my last dyno run, they are saying that one of my 310cc injectors are unbalanced. Is that possible to happend?
If so what are my options? How can I fixed this problem? Is there any other reason why I lost so much WHP since the last dyno run? I am still making power till 8500rpm, but no where near my previous run.
 

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You should have received a sheet showing the output of each injector, if you bought them new.

How does low compression in one cylinder equate to an injector problem?
 

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If I'm right the stock injectors are 240cc. You put 310cc (30% more fuel flow) injectors without tuning your fuel map? Your mixture must be way on the rich side.

one of your injectors is unbalanced? What does that mean?:)

174 rwhp means around 200hp at the flywheel.
Your modifications are very good I really like them , all you need is some dyno tuning and around 210hp should be possible. You should be able to take on the Type-R:)
 

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Discussion Starter #4
No, thats the problem I go to dyno shop and tune the 310cc and I had lost 23whp. They told that one of my injectors is not putting out the correct flow, which is causing a unbalanced in one of my cylinders.

Yes, They did lower the fuel psi around 25-30 at idle and at WOT it goes up to about 35-40. They also remap the vafc for the new injectors because I was running way to rich. When I had put the rc 310 in, I couldn't get my rpms pass 5000rpm.
When It would hit 5000 it would make a noise like it had hit a revlimit and would struggle to pass 5000rpm. But, now I can get it up to 8500 with
a loss of a lot of power.
 

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stop going to that dyno shop....

it's a self-fulfilling prophecy: they tell you to get bigger injectors (did they show you the duty cycle readout table from datalogging or were they guessing??).

if they were guessing did they base it on the wideband O2 sensor readout or was it a pure guess?


then you get a huge injector. it washes down the walls of your cylinder with fuel which removes the lubrication between the wall and the piston rings.

you lose compression from poor piston ring seal after running wayyyyy too rich.

then he tells you the obvious that you are losing compression after his advice was to get bigger injectors which caused the compression problem in the first place.

let's say for arguments sake you were maxed out on a stock 240 injector at 60-70 psi FPR (what was your 240 running at interms of FPR and AF ratio?). let's say for arguments sake the car wanted 280 flow rate at 50 psi FPR. you get a 310. why? because you can lean down the injector to 280 flow and run a lower FPR like 45 psi.

The bigger 310 injector isn't there so you can push it to 370 flow rate at 70 psi FPR. It's there so you can run a shorter injector duty cycle to get an ideal air:fuel ratio to gain torque and afford finer fuel control by leaning down without beating up the injector and fuel pump, thereby shortening their life.

they should have leaned down that 310 puppy using a wideband and fuel controller or ecu reprogram.

sounds like your dyno shop mate has you running in circles chasing your tail and making things worst rather than better. 23 hp without tuning? ...absolutely, anyone could have predicted that.
 

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Discussion Starter #6
I was runnig rich with my old injectors and the fuel psi was set
around 45psi at idle and 52-55 at WOT. But, they told that my injectors was max out and could not push the vafc any more then 10% which the vafc is about 15% max or something like that.
They said, since the only thing I did since my last dyno was changed the injectors, so that the problem is with my injectors. The guy said that one of my injectors might not be putting out enough fuel or to much fuel to one of my cylinders. They balance should be 310cc for each, but somewhere it is not balanced out that way in one of my cylinders. They did not do a compression test also. He told me that I should send them back to rc to get balanced out.
But, I never kept the box or my receipt. So, I am confuse as to what to do at this point.
 

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call RC and tell them the situation. They are very cool, good people.

if the problem is indeed in 1 injector and you received new ones, I doubt that the injector itself is off since RC tests their injectors and balances them prior to sending them out. As Gvtec said, they include the spray pattern and flow rate @ 42 psi FPR that was tested for each injector on a spec sheet when they send them out to you. Now if they are used injectors and you got them from a nonRC dealer or another owner, that's another ball game. I suspect that if they were new injectors and IF your dyno buddy is right, your problem is either in the injector clip wiring , injector driver, or in the ECU program....not the actual injector.

it's too bad you did not go to a shop with a wideband and it's too bad you don't have a datalogger. Either one or both together would give you a more precise picture of your tuning ailments.

BTW 240 cc/min pintle saturated stock injectors @ 55 psi FPR @WOT is NOWHERE near maxing them out. I know people who ran them at 60-65 psi set at idle...they didn't last as long compared to running them at 50-55 psi (vacuum line off) at idle...but they ran fine.
 

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Discussion Starter #8
Yes, The injectors are used,but were brand new and came with everything but the flow chart. I am running on a skunk2 chip ECU and I tuned it on that computer. I know I did not installed the injectors wrong. I should be putting about 180-85whp properly tuned. I've have been asking around and someone told that 310cc might be a a little to much for my setup. They also told that prelude injectors might work perfect for my setup.
Do you have any information on what my solution might be other than calling rc since I did not buy the injectors for them.
 

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get a volt/ohm (multimeter) meter and check for any breaks in the electricals going to the injector harness and the wires going to the cylinder 1 clip. There is a method to determine if the injector driver is being activated as well but I can't remember off the top of my head. You can run the multimeter across the injector clip prongs and turn on the car...I think...but don't quote me on that one. The last thing is to check whether the ECU is sending out to the harness. If your other injectors work fine then the problem is not at the harness, clip, driver, or ECU.

Honda stock injectors are pintle nozzles and do have a better spray pattern than disc. Disc are more reliable under high heat but not under high cylinder pressure like boost. Disc respond faster. 280 cc/min @ 42 psi FPR Prelude injectors after '97 (saturated type not low resistance unsaturated type ) would work great. If you look at the Jun Stage 4 crate motors making over 240 ps they use only the lude injectors...nothing crazy like what Sakai and the rest of them are using over at honda-tech...something like 370-440 injectors...nuts.
 

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Running 55 psi with vacumm line off and 240 cc injectors, what whould be the flow rate ?

Is this safe, can i expect ling life with my injectors at 55 psi ?

At 55 psi can i raise some + settings on my V-afc, like +15% or more ?

Before vtec i´m using -12% in my V-AFC, is it really lowering the fuel cicle ?

Thanks,

Pinota
 

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New Flow Rate = SQRT (new FP/old FP) x injector flow

= SQRT (55/44) x 240 = 268 cc/min

assuming your stock starting FPR was set at 44 psi vacuum line off. SQRT = square root.

A 20% increase from the stock max. range is safe for the injector life and still within the ECU fuel map calibration assumptions.


the max. stock FP is 55 psi vacuum line off on a GSR. You are not pushing the injector if that is your question since you are still stock!

So 20% over 55 psi is 66 psi FP vacuum line off.

is -12 VAFC fuel setting below VTEC decreasing your injector duty cycle? You have to confirm on a wideband but probably yes ...by how much I don't know. The MAP (intake Manifold Absolute Pressure) voltage is the thing that gets changed by the VAFC. MAP is an indicator of air flow delivery. So if you have faked out the ECU into thinking that it "sees" a lower air flow coming in, the program map should reduce injector duty cycle at those rpm points you entered for the -12. Again, by how much and how much of an air fuel ratio change that is would be guessing on my part since each engine breathes differently.
 

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lotta good stuff but did you see if they one was internally shorting itself. have a shop do an inj. balance test takes five min after inj. are out. some people run inj. cleaner like crazy , the same people seem to think if one bottle is good then 3 bottles is better. well anyway on the inside of the inj. their is a "casing" that keeps the coils of the inj. from breaking down and touching each other. using alot of the inj. cleaner breaks down the casing and eventually can cause the inj. internal resistance to drop causing the inj to dump fuel. and cyl. washing can occur real quick when that happens. this was a common problem when the motovac machine ( carbon cleaner) came out cuase everyone wanted to make money off the machine they carbon cleaned the car with these harsh fluids practically every time it came in , when once a year is plenty. just my .02 , agree with MD too.
 
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