gearhead_i_am

I need some advice on intake air temp. i have a boosted ls3 on 93 pump gas and no intercooler or water meth. what is a safe boost number and a safe intake air temp? right now at 11#s and 170 air temp and 13 degrees timing. can i safely run this?

The BallSS

iTrader: (9)

If you're using the factory IAT, there's a very good chance its much higher than that because the factory IAT is VERY slow to respond to temperature changes.
If you plan to run it non-intercooled, then at least switch to a RIFE IAT as they read way faster than stock and will give you a better idea of where your IAT's really are.
@Forcefed86 has played with lots of hot air setups, perhaps he'll lend his opinion.
I'd be making plans for some sort of cooler especially when using pump gas.

68Formula

And mount the IAT in the manifold or as close to the manifold in the intake tube as possible.

TrendSetter

Ls3 are already pretty high compression. I just had a ls3 corvette on the dyno with a ecs blower on 93 and I had to keep timing down around 8 degrees at 9psi peak to keep the knock sensors from going crazy. That was with an AA ic but I don’t remember iats off the top of my head.
my example was 100% stock other than blower and it made about the power I expected (552whp)

forcd ind

iTrader: (7)

I always tried to plumb the intake air from outside the engine comp., but not always possible. Not sure how you can exactly tell when intake temps become a problem, engine temps prob. become part of it. I have run over 200 IAT's w/o a known problem, more on a blowthru setup, but the science part of it prob. would make sense, dense air, etc.
I know I have trouble breathing in high humidity, so I guess my engine would too, lol.

wlink14

I want to say that is probably on the spicy side for a tune-up. Every combo is different but LS3s are higher compression, and 11psi is probably really pushing it on 93 with hot IATs.
I would look into either water injection or an intercooler, otherwise you might soon have malice in the combustion palace.
As for a safe boost number, you're probably about done on pump 93.
Intake temp wise, on my personal vehicle I cut ignition with IATs over 140*. Lower is always better. As mentioned above, the RIFE fast acting IAT sensor is HIGHLY recommended. My stock sensor was very slow to react, the difference is pretty incredible.

For reference, my tune up is 11.4AFR, 16* timing up top 14* at peak torque, 15psi boost with e85. Mild cam 6.0L 10:1 compression 7875 turbo. Highest IAT I've seen with Rife sensor is 130* at end of long run.

Forcefed86

iTrader: (4)

I agree with most of what was said above. You are on the edge IMO. I wouldn’t turn it up any higher. Did you gap the rings a lot? I’d get some water/meth on it at minimum. Spray it all pre turbo. The OEM pistons swell a lot more with pump gas than they do with e85. So even if you don’t detonate you can butt a ring easily. Even with a decent water/meth rig, I wouldn’t lean on it much harder than you are now.

All my setups were on Ethanol blends so I don’t have much exp with non-intercooled pump gas stuff. If you have E85 in your area, you could always blend up some E50. Great fuel that doesn’t need as huge of a fuel system.

gearhead_i_am

Well I got the boost under control at 8#s and the AIT followed at 150 degrees (90 degrees ambient air temp). So at 8#s i see 15 degrees timing. I gapped the rings so I'm not worried about that. I think this a safe tune. The knock sensers are silent so i see no sign of detonation.

The BallSS

iTrader: (9)

Knock sensors are only part of the equation, you should be reading plugs to see exactly what the engine is doing.

gearhead_i_am

Just pulled a plug. It looked great, timing color on the ground strap was great and the porcelain had no pepper flakes on it.

The BallSS

iTrader: (9)

Unless you just put them in with no street driving and made a WOT pull and pulled them you won't learn anything.
Get a fresh set, go to your favor spot, put the new plugs in, make a hit, pull over asap, pull them out and check them.
This is the way.

gearhead_i_am

Well I think i talked my self into water meth injection

The BallSS

iTrader: (9)

Cheap insurance my friend, plus you can wick it up a little bit more.
Lots of great options out there, build your own or buy a cheap kit, or buy an expensive kit.
I've been eyeing a kit from Alky Controls and Pro Meth, they make really nice comprehensive kits with controllers and everything.

91 Z28

iTrader: (3)

Best decision I ever made for my car. I've got an AEM kit spraying 1500cc. Gonna up the boost when I'm back home from work

Forcefed86

iTrader: (4)

Prices sure seem to have gotten out of control lately. It’s $60-100 pump, some push to connect line and fittings and a plastic tank. Why they think that’s $600+ worth of materials is beyond me. I just built one for my wave runner for about $200 ordering parts off amazon.

Bet I could have done it for $175 or less if I shopped around a bit. Just wasn't sure on the "off brand pumps" and the compatibility with methanol so I went with the 8000 series shurflo for $100 shipped.

91 Z28

iTrader: (3)

Covid happened and they saw the perfect excuse to jack everything up and keep it there.