do i need more injector?

[daturbosix]

so real quick...

built 109
BS3
champion ported irons and intake
gt6776bb
razors progressive single nozzel alcohol kit(but i run 100% M1 methenol)
57lb injectors, walbro 340 intank, hotwire kit
built 200-4r, and a converter way too loose

the car made 570 to the rear tires on 93 octane. 26lbs of boost. and squirting meth on level 6.
now, heres the issue.. even on base boost(15lbs) and the alcohol kit off, it detonates and knocks. turn the kit on, and boom, no more problems. i really hate runnning aroud with the kit on all the time, but its so darn hard to keep my foot out of it! lol

do i just need more injector? what size should i go up to?
at what point are stock fuel rails a restriction?

 

[krom]

On 55 lb injectors running high 10s I was over 100% duty cycle. Your horsepower is a 10 second car. Go 75 and better fuel pump(s).

 

[daturbosix]

At the point of going to a 75lb injector and better pump or pumps, do i need to worry about fuel lines and or injector rails?

 

[krom]

I use stock rails,fuel lines, 75lb injectors and a double pumper. My duty cycle running mid 10s is around 60.

 

[bison]

You should be able to run low 10's with those injectors and razor alky. Very low 10's. Without alky you will see detonation at 18psi. With high octane you have enough injector to run high 10.80 without alky

 

[daturbosix]

i really dont want to depend on race gas. i like the whole 93 and alky. i can fill up anywhere! and not pay $10/gal

 

[HelloBozos]

I've found if match your inj. size to turbo size ,works out pretty good, t48 with 50's, t60 with 60's ,t70 with 72's etc,etc..

 

[RmvBfrFlght]

so real quick...
now, heres the issue.. even on base boost(15lbs) and the alcohol kit off, it detonates and knocks. turn the kit on, and boom, no more problems. i really hate running around with the kit on all the time, but its so darn hard to keep my foot out of it! lol

I think we can all agree on the foot thing. As for the knock at 15 psi, need to back the spark advance down. Without the alky the octane is lower and the intake air temperature is likely higher. Not much else going on at 15 psi w/o alky and 26 psi with alky as far as lack of fuel delivery.

The only issue is you get into running two different tunes. One w/Alky & one without Alky.

RemoveBeforeFlight

 

[Blazer406]

RemoveBeforeFlight touched on the tune issue. With the alky chip.... it naturally tapers fuel off as the alky comes in.... and the alky starts to come in beginning at 5 psi or so with the stock settings..... so you will lean it out even if you are only running 15 psi with an alky chip and no alky.

Mine may quit tomorrow... but my kit has 20k+ miles on it over 7+ years.... still works fine and it comes on with the ignition and stays on.

Running my car without alky would be like drag racing a dump truck..... just not much fun at all.

Get a good audible knock gauge, conservative tune, alky, and let her rip all the time. Never get caught with your pants down.

 

[Fast Farmer]

What intercooler are you running? Go to RC fuel injection and use the injector worksheet to size your injectors.

 

[daturbosix]

What intercooler are you running? Go to RC fuel injection and use the injector worksheet to size your injectors.

PTE front mount

 

[Blazer406]

IMHO, your issue is running with the kit turned off. The chip is killing the fuel b/c it thinks you are spraying alky. You will likely hurt something running to 15 psi with an alky chip and not spraying alky if you continue doing that.

57# injectors are more than adequate at 15 psi on a turbo Buick V6.

 

[Blazer406]

I've found if match your inj. size to turbo size ,works out pretty good, t48 with 50's, t60 with 60's ,t70 with 72's etc,etc..

IMHO, if you are buying new injectors and your goals are 10.50's or less.... only buy 60# high Z injectors.... no matter what turbo you are running. 60's work fine on a 100% stock car. They work fine with a 550 HP TE45A car with ported heads and alky. They are a very versitile injector. They have been high 9's with alky. I think 80# high Z's would carry you well into the 9's with alky. 60# injectors would safely cover 90% of the people on this board.

 

[daturbosix]

IMHO, your issue is running with the kit turned off. The chip is killing the fuel b/c it thinks you are spraying alky. You will likely hurt something running to 15 psi with an alky chip and not spraying alky if you continue doing that.

57# injectors are more than adequate at 15 psi on a turbo Buick V6.

its a bigstuff3 car. no more chip bs.

 

[Blazer406]

Sorry, I am mixing threads..... On our xfi car, we still had to retweak be table when we were running alky vs not running alky. Even though the ECU can adjust, it isn't a good situation to ask it do adjust a bunch real quick. It will likely temporarily lean out regardless.

 

[Reggie West]

Agreed you are asking for trouble if you tune the motor to use alky and you don't use it.

Turn it on and leave it on.

 

[blackgn1]

I run 80's. Runs just like it did with the 60's. No change in idle or cruising. Single in tank pump and stock fuel rail. Fuel system upgrade is in the works.

 

[moving-violatio]

I hate to revive an old thread, but I have a question. If he went with the bigger injectors wouldnt he have to rely less on the alky. I have had this question for awhile and no one I know has answered it. I have had other turbo cars, and we just put bigger injectors in to compensate for amount of boost we wanted to run. Is this not the case with our cars?

 

[Paul Lohr]

I think the reason for using alcohol is better latent heat and specific heat values when compared with gasoline. The linked article gives a little detail on this. I have read the article a few times but still have not fully understood it.
http://www.innovatemotorsports.com/resources/rich.php

One thing I'd like to know is how the addition of alcohol affects the later stages of ignition. Does the pressure toward the end of combustion fall off more quickly when compared with gasoline only combustion? I've heard it stated that this later stage of combustion seems to partly determine whether detonation shows up.

Paul Lohr

 

[Blazer406]

I hate to revive an old thread, but I have a question. If he went with the bigger injectors wouldnt he have to rely less on the alky. I have had this question for awhile and no one I know has answered it. I have had other turbo cars, and we just put bigger injectors in to compensate for amount of boost we wanted to run. Is this not the case with our cars?

I think you are confusing bigger injectors and assuming the car will run more rich?

The bigger injectors should run the exact same AFR as the smaller injectors as long as the smaller injectors aren't too small to support that HP level. So as far as injector size affecting whether or not you need alky...... it shouldn't. IMHO, you should never size an injector for a car assuming there will be alky present during the combustion cycle....... IMHO you should run plenty of injector assuming alky was not going to be used.

When running pump gas and alky.... you are wanting the alky for cooling of the intake charge...... and also to add octane. If you run alky with race gas..... you are only wanting it for cooling only... as the alky is a lower octane than any race fuel...... so IMHO, you only want to spray enough to get inlet temps down..... again IMHO.