24lb injectors

dedoo · Post by **dedoo** » Sat Jan 30, 2010 12:34 pm

Hey guys please excuse my ignorance but I need an injector upgrade and I'm not sure what will fit or not.

I just went to ebay... and found thse

Ford blue top Injectors

will this fit or do I need to search for something completely different.

Eliot · Post by **Eliot** » Sat Jan 30, 2010 1:45 pm

What engine management are you running?
I've got a set of high impedance Chevy Corvette LS-1 26lb Bosch Fuel Injectors with very low miles on them.

dedoo · Post by **dedoo** » Sat Jan 30, 2010 1:48 pm

DTA pro8

Eliot · Post by **Eliot** » Sat Jan 30, 2010 1:50 pm

I will take a fair market offer for them - but not giving them away as they are always handy to have around.
They were on my chevy until I went turbo.

dedoo · Post by **dedoo** » Sat Jan 30, 2010 1:58 pm

I'm expecting between 300 and 310 bhp. It's btw a RV8. Which I should have mentioned in my previous post.

Calculating with .5 BSFC as its a naturally aspirated engine is a good start or should I bring this number down?

with 0.8 duty cycle 05 BSFC and 310 bhp would be 24lbs/hr right?

would chevy injectors fit?

Eliot · Post by **Eliot** » Sat Jan 30, 2010 2:39 pm

They will support around 330bhp at .5 bsfc and 80% duty cycle.
You can increase the fuel pressure a little which will get over 350 - but you will need alot of engine to achieve that. They are "standard" sized injectors, so they should fit straight in - I can take some measurements.

Bar in mind the TVR griff 500 ran OEM lucas injectors at 100% to get to their claimed power figures.

http://www.witchhunter.com/injectorcalc1.php4

spend · Post by **spend** » Sat Jan 30, 2010 2:43 pm

dedoo wrote:I'm expecting between 300 and 310 bhp. It's btw a RV8. Which I should have mentioned in my previous post.

Calculating with .5 BSFC as its a naturally aspirated engine is a good start or should I bring this number down?

with 0.8 duty cycle 05 BSFC and 310 bhp would be 24lbs/hr right?

would chevy injectors fit?

I'd spend your money in something else if I was you. IMHIO std injectors are fine for that power, larger injectors just make low load open times more critical. The std Lucas seem quite happy to have the pressure raised (some even swear they work better), certainly no need to worry until you get to around 350bhp from what I've seen.

I'd personally rather get (higher rated) Lucas injectors anyway, the Bosch variants choke the inlet port due to the large probosis they have IME.

Eliot · Post by **Eliot** » Sat Jan 30, 2010 4:21 pm

spend wrote:
dedoo wrote:I'm expecting between 300 and 310 bhp. It's btw a RV8. Which I should have mentioned in my previous post.

Calculating with .5 BSFC as its a naturally aspirated engine is a good start or should I bring this number down?

with 0.8 duty cycle 05 BSFC and 310 bhp would be 24lbs/hr right?

would chevy injectors fit?
I'd spend your money in something else if I was you. IMHIO std injectors are fine for that power, larger injectors just make low load open times more critical. The std Lucas seem quite happy to have the pressure raised (some even swear they work better), certainly no need to worry until you get to around 350bhp from what I've seen.

I'd personally rather get (higher rated) Lucas injectors anyway, the Bosch variants choke the inlet port due to the large probosis they have IME.

On a griff 500 I saw the lucas injectors at 100% duty cycle and leaning off towards 14afr - which doesn't seem that great to me.
They were replaced with 24lb ford injectors which got the duty cycles down into more sensible values.

Wrt to idle pulsewidth - well it just depends really. I went from 24lb to 60lb on the Dakar - with no issues. I verified that the idle pw would be ok by telling my ecu it had 60's in it and seeing what pw it gave at idle before purchasing.

spend · Post by **spend** » Sat Jan 30, 2010 5:34 pm

Dont want to argue but I know of a few modded TVR's haven't even bothered upgrading injectors until going North of 350 on Joos Rollers. A working pressure regulator will be a must for 300, and upping the fuel pressure a wee bit seems to have no negative effects.

I would think if you saw that on Matts car that his injectors were blocked or the pressure was not right?

Eliot · Post by **Eliot** » Sat Jan 30, 2010 6:55 pm

spend wrote:Dont want to argue but I know of a few modded TVR's haven't even bothered upgrading injectors until going North of 350 on Joos Rollers. A working pressure regulator will be a must for 300, and upping the fuel pressure a wee bit seems to have no negative effects.

I would think if you saw that on Matts car that his injectors were blocked or the pressure was not right?

No doubt you could just about squeeze 350bhp by upping the fuel pressure and running them at 100% duty cycle - and on the rollers at 20'c they would probably give the desired AFR. But they have nothing further to give do they. What about a cold night with dense air - you could start leaning out. The 80% duty cycle is there to give a safety buffer, eating into that buffer is a decision you need to take I guess.

Did you know matt?

stevieturbo · Post by **stevieturbo** » Sun Jan 31, 2010 8:25 pm

spend wrote: larger injectors just make low load open times more critical.

True, once you are over 1000cc injectors, control can get more difficult. Below that, if you buy good injectors and have a good ecu, there should be no difficulties.

But 24lb's are tiny !!!

The LS injectors Eliot has would work fine and no doubt have a far better spray pattern than any OE ancient injector found in a RV8

Ive a set here myself...although Ive pinched most of the o-rings for other stuff

spend · Post by **spend** » Sun Jan 31, 2010 8:54 pm

Before using any of those injectors, I would advise you set them and a Lucas side by side in an inlet manifold so that you can see them from inside the port. If you see how they obstruct the airflow you may reconsider

Make your own mind up it is pretty visible if you look (like the size of your little finger nail protruding).
ETA: Snap below shows the difference, maybe only significant on ported manifold/heads - but the only way we could explain 15-20bhp losses on a couple of straight swaps.

Pic shows an uprated Lucas BTW, but it is exactly the same form factor as the original Lucas injector.

stevieturbo · Post by **stevieturbo** » Sun Jan 31, 2010 11:19 pm

They are the same fitment. Basically a typical Bosch fitment. Ive never seen any injector intrude into the airstream, apart from perhaps old mechanical injection.

Robrover · Post by **Robrover** » Sat Feb 20, 2010 4:41 am

I recommend Ford Motorsport C302 Yellow top injectors - straight swap for Lucas items. Available from Five-0-Motorsport, Summit, Mustangs Unlimited, etc

r2d2hp · Post by **r2d2hp** » Sat Feb 20, 2010 8:55 am

I have a new set of Bosch Injectors that flow 234cc or 22.3ib @ 3 bar. Also have a used set that are as good as new that I used when my car was setup on the dyno at Dave Walkers

The above injectors work fine on my engine fitted with supercharger which was from 4.3 TVR Griff

Last setup on Rollers was showing 314bhp

They are low impedance so need ballast resistors but I do have a set for 14cux and Emerald ECU

PM me if interested