I am having issues with #7. I have nipped the ground strap twice, and this weekend on an 1/8 mile pass I grenaded the porcelain. I was on C16, AFR was between 12.0-12.4 and the timing was a mere 16 degrees, 16 psi average boost over the pass as well. We had been pulling plugs all night and reading them and all was good....the timing was actually low and fueling looked very solid.

I have a Typhoon intake and I spray meth from 2 nozzles located pre-TB. Total meth is 12 GPH. I think it is a distribution issue. Not sure if I should blame the meth, the intake or both. Or, something else? This engine has TFS220 heads, compression is roughly 9.7 and it has a 235-237 cam on a 115 +5 from LJMS.

Maybe I should kill the meth for C16 and tune AFR off of pure gas? I cannot individually pull timing from that hole or richen it up, this car runs on Microsquirt and it is batch fire. I have ID1000 injectors. Duty cycle on this pass was roughly 80%.

BR7EF plugs, gapped to .025.

Ideas?

 

Had your injectors flowed? Can try sticking the richest injector in that hole. Any pictures of the plugs ground straps? I'd keep lowering timing until it's happy, may be the only option. Whats the timing table look like? Can always drop it 3-4* at peak torque and ramp it back in.

Might be time to run an engine management system that can adjust fuel trims to individual cylinders.

 

pull that injector and check it for debris in the screen. your afr is based on all cylinders and if that injector is plugged you might be melting one hole down. you might try swaping it to a new cylinder and see if the issue moves. just a thought.

i whould give it a little more fuel just to be safe . i dont think getting the afr in the mid 11s will hurt it . but it might cool things off a bit.

 

always spitting the knowledge...

 

And/Or bullshit depending on who you talk to... but I try!

 

I really don't want to run C16 in the mid 11's. This thing rolls coal like a diesel when it is that rich and likes to push water on a rich tuneup. I am going to pull the fuse out of the meth and see how it likes that.

 

How would pulling meth help the situation any? If it's burning off electrodes it's a too hot. Pulling fuel isn't going to help IMO. Run a cooler plug, Drop timing, and/or add fuel.

Know your cranking compression by chance? (just curious)

 

The reason I want to pull the meth is because I am fueling the car based on what the 02 is seeing. That is a mixture of all of the cylinders. If it is not being distributed evenly, that back hole could be much leaner. Remove the meth from the equation and I am now just fueling from the injectors, without an airborne second fuel that must make its way all the way to the back of the intake. I think I can get the fuel more accurate, that is all. I will leave it for pump as I run a much more conservative tune with pump and meth.

My cranking compression is 135-145 psi.

Mike

 

id still check that injector inlet screen. i have seen them full of crap. i have had guys build new systems and cut lines and get tons of stuff in the lines then turn the pump on and push all that stuff into the injectors instead of rinsing the lines first. and all that was needed it to clean them up . not saying you did that. just that it dont take much to plug them part way. good luck on getting it fixed.and i think you are better running just c16 and no meth. i can't see why you need the meth with good fuel.

 

If you’re not flowing/cleaning the injectors I’d swap #7 to a new cylinder. That way if the problem follows to another cylinder, you know it’s the injector. (can inspect it at the same time as well) Then drop timing 2-3 degrees until you figure it out. Did you Sync the timing on the MS? I’ve seen timing sync way off as well. Maybe your 16* is really 20*.

 

Good info. I would think that the timing is whats doing it. Also dont forget that sometimes we expect a little to much from pump/alky.

 

It was on C16 at the time. Average timing on the run was a little below 16 degrees. I think the cylinder is lean, probably substantially leaner than the others. I am blaming the meth.

 

How about... Not pulling the fuse for the meth. But run pure water in the meth system until you get this figured out. I would do like the other guys say and switch injectors around, or get them flow tested, but if you're gonna keep running it without ruling out an injector issue, I would run distilled water instead of turning that system off. Might save you from a rebuild.

 

Be careful shutting off the meth. Yes the end feed stock type manifolds favor the rear cylinders.

But the thing about the meth injection distribution is it will be tied to air distribution. Pull the meth off and it could be well short in back. Something to think about

 

I will pull the meth and richen it up substantially for safety. I also am going to try an LS6 intake. I don't have many options if I want to keep my hood.

Mike

 

i assume your fuel pressure is stable and reasonably psi? (not 100+)

i agree, and what i have heard from ID lately that you should check that injector.

i agree that if you cut meth your rear cyls will go leaner. spray test the meth system? those nozzles can clog too.

i agree that i would never in my life run 16# boost in the 12's AFR

I have never experienced enrichment being a cause for head lifting. power and heat go down, heads stay down. at 16# i would be mid to low 11's.

probably irrelevant but i would never run a typhoon intake.

 

Nipping plugs with C16, 12.0:1 AFR, 16 psi, and 16 deg of timing with that compression ratio and cranking compression.... I would be pulling the injectors and getting them checked just because and consider switching away from that intake and putting a stock LS6 intake on. If you have an aftermarket computer MAKE SURE that your timing is accurate. C16 burns pretty slow so that timing isn't out of the ordinary assuming it's accurate.

 

I am selling the IDs and going to a 127 pound injector.

Of course the rear cylinders will go leaner, that is why I am going to up the fueling. I want it fueled only on C16 for high boost. I do not want to rely on an airborne fuel that has to wind its way through the intake and into the ports.

The AFR was 12.0 average. This is not pump gas, you can run C16 much leaner. The fuel tuning was done by someone who has what I consider vast experience and who I trust.

My base pressure was 43 psi with a 1 to 1 rise per psi of boost.

The leaner it got, the less it pushed. I check the overflow after each pass, and it was barely pushing at the end. I have read every thread on here and over at YB on pushing water. One thing I took away was in many instances, people were having issues with rich tunes pushing. The engine has to come out either way, the deck surface is in need of attention, so I figured I would see what happened as we leaned it out.

I see a good deal of hate for the Typhoon. I personally know someone who made 1200 wheel on one. It was $100 from a friend, so I gave it a try. In my mind, that is better than cracking a $900 FAST with boost for 10 HP over an LS6. I will try an LS6, I had an LS1 beforehand.

 

fair enough, lets approach the tune after you verify the injector is good.

i definitely do not have vast tuning experience but at this power level my spark plugs lasted years not passes.

 

ditch the meth, run straight water injection with the c16, and flow the injectors and put the 2 fat ones in 7+8. There is something wrong, there is no reason you should be having issues with only 16deg and that boost.