Need some thoughts on tuning my stroker motor

[DaveB]

I had a 4.6 stroker motor built for one of my Jeeps but I'm not getting the power out of it that I should. I am fairly sure its not getting enough fuel when it gets near full throttle (starts to clatter). I put in 24 lb/hr injectors but haven't bumped the fuel pressure up yet. I need an air/fuel mixture gauge to get an idea as to where it is running. Does anyone know of a good wide band meter to buy ? Will I need to have the computer re-flashed ? The electronics are out of a 93 XJ and the electronics have always run the old motor a bit lean. The motor was built .030 over, Keith Black forged pistons, 4.0 long rods, bigger throttle body, free flowing intake and exhaust, new distributor, high flow water pump, and a good head.

If I have to seek help does anyone know of someone who has good experience with these motors that I could take it to ?

 

[thenag]

I got my Jeep dynoed at Turbo Labs, Joe seemed to know a lot about tuning. He did check my air fuel ratio while dyno-ing and said it was near perfect and he wouldn't advise any further tuning. You could probably call him and see if he could tune it and what it would cost. (my guess is $$$)

On my 99 stroker with what ever Clegg gave me, I installed the Ford injectors. It turns out the Ford Injectors deliver 15% more fuel than the OEM ones and 4.6 is 15% more than 4.0. So for the 99's all the tuning that needs to be done is Ford injectors.

Remember when comparing injectors to keep in mind the psi, I seem to remember that the Ford's are 24lb but a different pressure, but when you compare them at the same pressure it is 15% larger.

Flyin Ryan is the guy I was thinking of using, quite expensive.
http://www.frptuning.com/

Both Turbo Labs and Flying Ryan would use the same SCT tool for my 99

I feel your pain it took me a year to finally get mine figured out, turns out my exhaust was too small. (it probably should be even bigger but it should be ok)

Since mine seems to finally be running correctly I will probably dyno it again soon.

Nathan

 

[DaveB]

I did some online searching yesterday and one of the challenges I have is the obd1 computer. Your 99 is obd2 and Flying Ryan and others can reprogram that one but Ryan says he can't do anything for the obd1 rigs. I have the 24 lb ford injectors in mine but the obd1 fuel rail pressure is lower than your obd2 99 (32 vs 49). I am hoping that when I install the adjustable fuel pressure regulator that I can get it to provide the fuel flow I need. What exhaust size did you end up with ?

 

[thenag]

What exhaust size did you end up with ?

2.25 inch all the way, it has non-mandrel bends so not super high flow.

seems like rule of thumb for exhaust is 2.25 is good for about 225hp, and 2.5 is good for 250 hp. But you will always find people that swear they get 300hp out of 2.25 exhaust. Joe from turbo labs said for what I am doing 2.25 would be great. (my issue was no space for a down pipe with a uni-body and a d60... the solution... time and $$$$)

It sounds like you have an idea where to go, more fuel.

Nathan