Glad you made it over! There is a lot of great knowledge here (as you see). You will get some good info to say the least.
That is all good information, but the comment I was replying to was "at those compression ratios", not boost (pressure) levels.
Compression never changes. It doesn't matter if you are compressing 1 ci of air 12.5:1 or 200 ci of air 12.5:1, you will be consistantly compressing it 12.5:1.
But your comment had nothing to do with this thread. I never said pump gas was bad for 9.7:1 compression - I said pump gas was bad for a 9.7:1 compression motor with 18 pounds of boost through it. The idea if it being literally 'crazy' IMO to run pump gas wasn't just because of the compression - it was the compression with 18 psi on top. I still stand behind it is STUPID to tune any modular motor with over a 9:1 compression with 18+ pounds of boost on pump gas.
How did the plugs look in each cylinder? Did I miss that? When I used to run nitrous, detonation would always take out the plugs first.
True Paul, but another 'sweet spot' to check is the heads. Like to see a picture of those as well. Valves can be very telling as well when looking for detonation.
One thing I have found is that on ALL of our cars the #8 is quite a bit hotter and more and more I am liking the idea that JPC did of tapping into the freeze plugs and routing that hot water from the rear back up to the crossover. No way on earth I am
not going to do that on my next motor. Must have on big boost applications IMO.
As pointed out, cylinder temps are not equal at all so just because your a/f says so and so doesn't mean one or more of the cylinders aren't getting beat to shit. Goes right back to CONSISTENCY - not just a word for performance down the track and off the line, but an important word for temps and distribution factors as well.
I'm new here - recently purchased a '09 Mustang GT for a daily driver and plan to do some HPDE events at VIR beginning next month. I've been road racing a C5 Corvette (dedicated track car) with a naturally aspirated forged 383 stroker engine for the past five years at a number of road courses on the east coast.
I installed approx. $9K (parts and labor) to improve my GTs suspension, cooling and braking performance. I have a "Wish List" for my Mustang GT, which includes a Livernois Motorsports 4.6L Modular 298ci Stroker Shortblock. I'm watching this thread to see how this company stands behind their product warranty when things take a turn for the worse for a customer.
This forum looks like an excellent resource - I recognize a few members from my club. I hope to be a positive contributor in the near future as I learn more about my Mustang GT. Thanks! Mike
Welcome to the forum...
I hope everything works out as well but I'll tell you right now that despite what some people may say in this thread or how they word it I can just about garuntee you that behind closed doors, anyone who is experienced with making big power on the modular motors will say it was
stupid and
crazy to try to push 18 psi through a 9.7:1 motor on pump gas.
I'm not a shop so I don't have to be nice or 'PC' - I'm just calling a spade a spade.
I'll do you one better - I challenge anyone on the forum to call JDM Engineering, JPC Racing, RGR, ST Motorsports, Livernois, Boss 330 racing, Lethal, PMP Performance, Powerhouse, Brooks speed, or any other of the known reputable A-Class 3V tuning guys out there and ask them this question...
"I have a Livernois built 9.7:1 stroker motor with 18-20 psi on top - can you give me a good pump gas tune on it...?"
Watch how quick they say... "NO - I DON'T RECOMMEND TUNING IT ON PUMP GAS - I CAN GIVE YOU A PUMP GAS TUNE AT LOWER BOOST AND THEN A RACE GAS TUNE AT THAT LEVEL"
You can take that to the bank.
If I bought a $15,000 Al Papito motor that was sold as 'good to 1600 rwhp' and then I put an F1 on it and ran 30 psi with a 100 shot of nitrous on top on 93 octane and detonated it to high hell at only 1000 rwhp - would Papito be responsible for fixing it? Of course not - he would simply call me an idiot and ask me why in the hell I wasn't running C16 or C23 through it.