I had my truck dynoed a coupe months ago after a 2 year wait. Thanks to Patriot for totally sucking and causing us to yank the motor 3 times due to head failures..... anyhoo a basic rundown on the motor:
Fully built
LFP TB
16cc dish pistons
H-beam rods
patriot heads
equal length shorty headers
stock cams
2800 SCT mass air
TR7 plugs gapped @ 28
and a whipple at 17psi

It made 535hp and 585 rwtq with the detonation.

The problem I am having is that I have had it re-tuned several times, and now its down to 9.5 degrees timing and its still detonating. I searched the board and everyone else seems to be using around 12 degrees timing with no issues.

It only happens at the top of second (4700 RPM+) and third gear (4200RPM+). I dont know what to do, A/F is 11.5 +/- .2 depending on weather.

Does anyone have an idea? I am open to any and all suggestions. The only option I can think of is just to keep dropping the timing until it stops. I just cant understand why when it was stock I ran 17 degrees timing on 13 psi and now I cant. I just dont know..

Thanks
Josh

 

is your IC pump working?

How old is your fuel filter?

Are the vac lines properly routed?

What is your fuel pressure at?

Are you on stock pumps/injectors? you may be running otta fuel?

I'd tryTR6's at .030-.034 should do you fine.

where are you located, who is doing your tuning?

Let us know,

Good luck

 

listen to Haybale

 

is your IC pump working?
YES

How old is your fuel filter?
original

Are the vac lines properly routed?
YES, after checking several times

What is your fuel pressure at?
not sure, Tuner never said

Are you on stock pumps/injectors? you may be running otta fuel?
Dual 255's and 60lbs inj

I'd tryTR6's at .030-.034 should do you fine.

where are you located, who is doing your tuning?
Tyler Tx, and Murillo Motorsports in SanAntonio.

The truck sat for 2 years but has had several tanks of gas run through it and a tank of 115 The dyno showed the A/F was fine at top end.

Thanks
Josh

 

I change my fuel filter every other oil change, cheap insurance

what compression ratio is your new engine?

Possible bad COP, check your engine grounds

 

Your low timing is due to the continued detonation you have been having. Everytime you detonate you take away a bit of aluminum from the area around the spark plug area and if you have steel inserts that most have with a built combo you are exposing the insert and the insert is now the hot spot in the cylinder causing you to not be able to allow more timing.

We get these kind of problems quite often from other shops using the wrong inserts and/or poor tuning causing detonation issues and when we wind up tuning them correctly we cant put much timing in it due to the already eaten away spark plug boss area.

Most likely you will have to pull the heads and have them fixed.

JJ

 

The heads are actually factory 8 thread heads, no inserts. After all calculations we figured the compression ratio is 9:1. Murillo said he only had one other lightning that detonated this bad and they turned his timing down to 7 degrees to make it stop. I wish i was closer to one the lightning tuners on the board, all I read is how great they all are. Murillo is an awesome dude but he doesnt do lightnings everyday. What kinda power loss am I seeing with low timing?

Thanks for the replys.