I've seen some guys put a real low timing # up at the very top of the timing scale (above the typical using range) so if the boost goes out of control the timing get pulled - what do you guys think??

 

If you do a wideband on the A pillar, it's not to bad to keep an eye on it even in WOT. Some are programmable so they will flash or turn red if you get lean, so you may not even have to look directly at it.

For every successful stock LSX boosted story of low boost, good fuel, and babying low RPM's (which kind of defeats the prupose of going boosted in the first place IMO), there are others that did all that and didn't make it to their first oil change before they were looking at a rebuild. I'm not saying you can't do it, because you can. I am saying if you want to avoid having to worry about it at all, and as the OP has asked what to do from keeping yourself away from blowing the motor, the best way would be to forge the internals and go with a lower CR.

 

I'm building a similar setup and was curious what kinda compression you're running? I know with meth it wants more just kinda not sure how high is too high.

 

I had 4 banger 2.5 liter stock cast piston motors that were turbocharged living at 400 to the wheels, 500 crank on straight 93. My secret was always conservative timing and a little on the rich side on air fuels. If you think about it and double a 2.5 to a v8 motor it is much the same. That equates to around 800 or more at the wheels (2.5 motors had to go through all wheel driver transmissions that had a conservative 15-20% drivetrain loss at the minimum). These motors had 8.5-9.0:1 compression and boost in the 20-22 psi range on nothing but 93 octane. I also kept timing in the 8-10 range at peak torque and 15-17 range at peak rpm. Different motors like different things, but I figured I would throw it out there. A 700 hp LS motor may only want 8 degrees of timing at peak torque and 12 degrees of timing at peak rpm. You just want to find what your motor is happy with.

 

The smaller and more efficient the CC is the less lead is needed because the flame front travels faster. Can't really compare a small bore 16v 4 banger with a 2 valve LS motor.

I made over 600hp on my 2.0 at 34lbs of boost. Ran 5* at peak torque and ramped up to 13* by redline. Others made more than me on pump gas using 0* at peak torque and 9* out the top. But again apples to oranges there.

 

Good info.

 

no way to compare the two...
also, double the Ci, does not equate to double the power...it just doesnt work that way

also, head/chamber/valve design has a lot to do with timing...

LS heads are Very efficient.....so it needs way less timing
that 4cylinder engine is not very effiicient in comparison....and it wont build as much heat or as much cylinder pressure as an engine with twice the power...

 

Great post. Will help keep me in check when I get my project going,
Ron

 

No but interestingly enough, the motors in stock form would run 25* of timing with their tiny turbo. By increasing just the turbo size you would have to run about 10* less timing to avoid detonation and would make 100 more hp. No it is not apples to apples, but I can almost guarantee those motors stock made about 150 hp without the turbo. As you said, more efficient less timing.

 

Did we cover everything guys?

 

Bump for a good thread!!!

 

If you have the means to log your car at the track always do so. I log every pass now. The one time you don't log the pass you'll wish you did. Plus you can email that data to your tuner if you have questions about how it's going down the track. I got a good config file from my tuner that has everything we would need and I use that on the HPT box to log.

 

I setup logging to start past 50% tps

 

Is there a certain HP/boost/compression ratio where race gas should be used?

 

Use good fuel if you're looking for big power. 91 is the best I can get around here, unfortunately. I've now invested in a Meth setup for the street. But I'm still going to keep the tune conservative whenever using pump gas. It's just not trustworthy enough to bet your engine on.

Don't install a boost controller the night before tuning so that you can get tuned for MOAR power. It doesn't leave you enough time for testing to make sure you have everything hooked up correctly before putting it in the tuners hands.

USE GOOD FUEL! and set your goals in steps.

 

just stay within the limits of your setup... you know when your pushing something, if you dont want to risk anything, dont. that extra 50hp may not be worth it to you. simple

 

I usually don't type in threads like this but I want to share an unusual situation regarding timing and boost.

My combo is a fairly radical solid roller 408 with an F2 procharger on c16 fuel and water 2 air intercooled.

I first started running the thing around 15-17 lbs of boost and 16* of timing. Getting it sorted out, I worked my way up to 21* of timing and that is where it ran the best numbers. Never tried any more than that.

Later I started running about 25 lbs of boost and started timing back at 15*. It was a total turd and the plugs where showing no heat. So I started moving timing up 1 degree at a time and it kept picking up mph. It was lifting the heads pretty bad once I got to around 21* again, but that is where it was running the best numbers on the track. I ended up tearing the motor down after the pass in the video below, but it would not surprise me at all if it kept picking up with more timing. I could never get a decent amount of heat on the plug.

I'm posting this because as others have said, and I agree, the best way to tune is by reading the plugs. I've just got a weird situation here where the cylinder heads wouldn't stay down before I was able to find a max power tune according to the plugs. Weird to me but whatever..........4-bolts around the cylinder suck.......but the ford guys seem to have it under control.

If I remember right this vid was around 24-26 lbs of boost and 21* of timing. We put the go pro under the hood cause we couldn't figure out where the little droplet of water under the hood where coming from. The water would be almost completely evaporated by the time we got it back to the pit spot so we had no idea it was doing like this. My jaw hit the floor when we watched the vid back at the trailer.

 

Interesting post Blown06. Goes to show that even if the motor is responding favorably, there is a limit. My guess is that F2 was probably working the motor harder than a turbo, making your threshold a bit lower.

 

Put it on a engine stand.. Best, foolproof way to not destroy an engine.

 

Brilliant insight. Please, go on....