ChevyChad

iTrader: (50)

How do you know when to stop moving the timing up tho if you can't judge it by KR?

hellbents10

iTrader: (10)

By power increase. If its going up in power still add more till you see returns diminish, the back it of some. Or a lot more then a little if running pump fuel which is junk.

ChevyChad

iTrader: (50)

Well, it appears that this car made a pretty substantial improvement with 2°, got no KR, and still blew a head gasket. So how do I know where to stop before lifting the heads and blowing a head gasket...

Got Me SOM

iTrader: (2)

there's really no way to know. just make sure you have plenty of fuel like 11:1 and maybe keep your timing at 14 max. you can add meth on top of that for even more safety factor.

2 degrees can add A LOT of cylinder pressure.

ChevyChad

iTrader: (50)

14° with meth? That seems really low? Slowhawk- what was the timing on that car you were talking about with the 346 F1?

Got Me SOM

iTrader: (2)

14 degrees is conservative and yea low but i guarantee you wont lift heads. you're running a F1 which pushes a lot more air. i think kp only runs about 15 degrees of timing and he runs on c16

on my old supercharged car with approx 9:1 compression with 12 lbs, I had about 19-19.5 degrees of timing. no meth. 224/230 cam

Tiago

iTrader: (27)

Chad

some of it is experience, with an F1 and the power it WILL be pushing if its all correct.... I think 18Deg with meth will be generous.

Jake@EPP

Push it till it pops then back it off a little bit

Just be happy with running it safe even though your not making the most hp, its still better then slapping gaskets on.

ChevyChad

iTrader: (50)

Alright guys, thanks for the info. I'd really like to know a general "ballpark" range for the timing. I agree, better safe than sorry, but I don't need to be 'wearing a life jacket in the kiddy pool' safe either. Definitely know now that 20° on pump gas alone is too much now... So you guys think that 20° would still be too much with the meth added? I just kind of find that hard to take in because I was running 20° and no meth with the P1 and everything seemed fine. But you guys know more than me because you have been there and done it. Thanks again for all the help guys

52172

iTrader: (2)

17 deg I say is safe for pump that what I am at, but only 10 lbs of boost. I'd say at the power level your gonna be at with 15 lbs drop two degrees of timing to be in the same safety window.

ChevyChad

iTrader: (50)

Are you running meth?

52172

iTrader: (2)

No meth just an oversized air to air fmic. I know my tune is safe, the thing that scares me is the guy from speed inc says the premium pump gas octane ranges from 85-93 octane depending on the batch so his recomendation was to tune for max safe power on 87 octane or regular gas that way if you get a bad batch of gas your gonna be safe. I add octane booster just as a safety measure against a bad batch of gas.

ChevyChad

iTrader: (50)

So take your 17° and, subtract 2° because I'm running 15psi vs your 10, and add 2~3°, maybe more?, more back in for the meth I'm only running the ATI twin intercoolers for now, but am going to be adding a 24x12x4 FMIC soon enough, so we are not really comparing apples to apples unless you are using meth and an intercooler...

Got Me SOM

iTrader: (2)

You are better off running more boost than timing.

I would tune it for pump gas without meth and have meth as the safety factor. If your meth system fails you can detonate. Meth doesn't guarantee you can't blow your car up,its happened to mighty mouse, and a local guy here that had a 1000 hp mustang.

your car you do what you feel like. I'd sacrifice 30 hp for reliability.

ChevyChad

iTrader: (50)

So you are saying I'd be better off running say 17psi and 14° timing than 15psi and 18°?

I have no problem sacrificing 30HP for reliability and safety. I have no problem sacrificing 100HP for reliability and safety. But sacrificing 100HP for no reason seems silly to me if it is just as safe (or very close margin of safety) to run 18° as it is to run 15°...

Got Me SOM

iTrader: (2)

yep that is what I'm saying.

there was a member here that put that theory to the test. I forgot his name but he had a 1000 hp truck. He compared more timing same boost versus more boost less timing. He ended up making more power with more boost less timing.

18 degrees on the street under load may detonate, its different than being on a dyno. If I were you I'd datalog on the street with a wideband hooked up and tune that way.

good luck

kp

iTrader: (34)

I only run 14-15 degrees of timing at 18psi, at 15 psi there is very little difference in ET/MPH between 15 and 18 degrees of timing on mine so I leave it on the low side.

ChevyChad

iTrader: (50)

Hmmmm thanks for the insight guys. I do have a 3.7 pulley that I think would give me probably 17psi. But I'll see where I end up at with the 4.25 and low timing. I'd really like to see 700rwhp but I guess its a moot point when 600 or 650 will spin the tires just as much on the street as 700 LOL

kp

iTrader: (34)

I wouldnt worry too much about dyno numbers, I have done a few things on the dyno that have picked me up a solid 30-40rwhp and went to the track thinking I was going to pick a bunch and nothing happened.

Use the the dyno as a tool to get the most you can SAFELY and go have fun with the car - thats what its all about. Pulling heads/engines every week gets real old real fast

ChevyChad

iTrader: (50)

Good point kp. Its just a number anyways huh I don't even take my car to the track that much at all anyways. It is on the street 99.5% of the time with street tires. Guess there is no point getting greedy.