timing and iat

[old motorhead]

This sounds like a myth busters episode. Interesting discussion. I have two Maggie TVS2300 setups. With my Vette with LS3 and 9ish psi, the IAT's at the end of a run depend totally on the IAT's and OAT's at the start of the run. They pretty consistently go up 40 to 45 degrees from the start to the finish.

With airflow over the h/e, the IAT's are 9 to 12 degrees over ambient. 95 degree day, it's 105ish at the start. Mash it from a 30mph roll in 95 degree temps and IAT's will get up to 140 at 140mph. If I don't brake too hard, I can turn around and do it again without going much over 140 degree IAT's. Waiting in line at the strip is a whole nother story. IAT's start at 20 to 30 over ambient and go up from there. 2nd gear burnout can make it worse yet.

My other TVS2300 is on a built LQ4 6.0L in a half ton flat bed truck. The h/e is a full size radiator with e fans mounted on the bed of the truck. It never heat soaks. Always has cool coolant going to the intercooler. IAT's ebb and flow almost exactly like the vette only the truck isn't dependent on forward motion for airflow over the h/e. I can run the snot out of it in hot weather and the IAT's go down immediately after I remove my foot from it.

Running more air through the motor after a hard run also cools IAT's quicker. If you slam the throttle shut after a run, it doesn't cool near as quick as leaving it in a lower gear and having the throttle open a little when slowing down. Oh, and after a hard run, the blower is the coolest thing under the hood. It has its own radiator

[dan0617]

Your findings are what I usually hear and see on top mount setups. If you were to pulley it for 12 psi id bet you would see 160 degrees too.

[realcanuk]

Originally Posted by dan0617

Your findings are what I usually hear and see on top mount setups. If you were to pulley it for 12 psi id bet you would see 160 degrees too.

Seems everyone has different results. I run 12 lbs on my eforce and dont see 160.

[old motorhead]

Originally Posted by dan0617

Your findings are what I usually hear and see on top mount setups. If you were to pulley it for 12 psi id bet you would see 160 degrees too.

Actually, the truck setup is running at 12psi. 3.1" blower pulley on an LS2. It has a multi function gauge that I always have reading IAT's. I've never seen it that high. It probably holds 3 gallons of h/e fluid along with two h/e's though. I have seen the vette's temps that high, but they were probably 120 at the start of a quarter mile run due to waiting in line 20 minutes, idling, before the run. Maybe I need to get the wife to push my car to the line so I can have the motor off with the hood up......hmmmm, think I'll ask her next time at the track. I wonder how that's going to play

[ayousef]

Originally Posted by dan0617

Timing depends on IAT in my tune. On a 65 degree day, I see IAT at the top of 2nd gear at 114 degrees and timing at 14.5 degrees. By the top of 3rd I see IAT at 159 degrees and timing at 11.5 degrees.

I am surprised to see timing pull that much with that temp but I guess that is what is safe. I'm also surprised to see IAT's climb that much, but is still better than the top mounts I've seen. This is with a Vortech Si trim ECS kit, 12 lbs of boost on a stock cammed L99.

What is everyone else seeing for IAT's after a 1/8th or 1/4 mile pull in 60 or 70 degree weather??

show us a pic of your engine bay, where is your filter located at? please dont tell me above the drivers side manifolds? I call it the VERY hot air intake (HAI)

[2SSCAMARO]

Originally Posted by realcanuk

Whats interesting here is that you are pulling no timing out at 140 degrees. I dont know the details of your build but most tuners do pull at least a little by that temp.

My tune does in fact start to pull timing at 140 BUT I only reached 133* at the point I lifted past the traps. The 141.5* temp was reached during deceleration.

[dan0617]

It is an ECS kit, filter is on the blower. I've been told when moving there is plenty of cold air there. Maybe not? Maybe I should get the Vortech air inlet tube or make one or something and see if there is a difference in IAT's.

[2SSCAMARO]

You need to be careful not to mess with the laminar flow through the area of the MAF sensor. You don't want a trade off....a bit lower IAT's coupled with new founded MAF issues in place of your current IAT's. Home made and modified CAI systems can sometimes be problematic.

[dan0617]

IAT sensor is in MAF, and MAF is after blower and intercooler. Anything I can do to get cooler air into the blower will not affect the tune, as the MAF will just see lower IAT's and adjust timing accordingly. Shouldn't need a tune change at all.

Jannetty can sell me the Vortech intake tube and his large filter. I'm just trying to figure out if it will help much or not before I purchase it now. By searching alot say yes, and alot say no. Ugh.

I think I'll give it a try. I also removed some of my plastic inner fender so when I do this, the filter will be exposed to alot of fresh air. Might get more dust from the tire, but I'll clean the filter plenty often. I'll post up the IAT difference when I get it installed and datalogged. With the filter mounted on the blower intake, IAT's pretty much hit 160 at the top of 3rd on a 2nd and 3rd gear pull. They don't go over 160 though even if I stay in it. This should be a nice before and after test in real world street driving.

[grocerygetter]

I'm curious for your testing results dan0617

[HtownSS]

Curious as well.

[dan0617]

OK, testing done. Back to back. I installed Vortech tube and cut a hole in front inner side of plastic inner fender. All runs were from 25 mph, up through the 3-4 shift, shifting automatically.

Run 1: About 78 ambient, Vortech tube installed, same ECS filter and restrictor. Coolant temp at start of run was 176 F. Not heat soaked at all. Boost only got up to 8.4 psi. IAT got up to 145. I'm sure it was lower due to boost being lower.

Conclusion 1: Vortech tube with same ECS restrictor and ECS filter does lower boost quite a bit. Must be a decent amount of restriction.

Run 2: About 83 ambient, Vortech tube installed, same ECS filter but removed restrictor plate completely. Coolant temp at start of run was 187. Boost got up to 10.7. Kind of in line with me seeing 11.5 on a 70 degree day without Vortech tube. Pretty sure this was a comparable test, but need another test to confirm. See below. IAT got up to 163.

Conclusion 2: Removing restrictor mostly made up for Vortech tube restriction. Also now not thinking the tube is helping IAT's much.

Run 3: About 86 ambient, Vortech tube removed. Back to ECS filter and restrictor on blower, as before. Coolant temp at start of run was 192. Boost got up to 10.4. Very close to the above 10.7, probably difference of ambient making the slight difference. VERY comparable back to back test now. IAT got up to 165.

Conclusion 3: Back to back testing, similar boost, only a few degrees difference in ambient, the filter and restrictor on the blower being ran at the hottest time, only saw 2 degrees more IAT at the top of 3rd gear. The Vortech tube doesn't lower IAT's. I started all the runs from a roll, but Run 2 and Run 3 had nearly identical IAT's at the start of the run.

A couple other nice conclusions I noticed for my setup: No knock retard anywhere on all the testing. Fuel pressure held beautifully. Also, through all the testing and all the changes, the AFR stayed about spot on, not much change. Jannetty's tune accommodates perfectly for changes in ambient temp, filter restrictions, etc

[dan0617]

Another thing I should add is that I can run back, to back, to back, then let it sit and heat soak, then run back to back and cannot get the IAT over 170 no matter what.

... and from all my logging to date it appears that about 10 degrees increase in ambient temperature equals about 0.5 psi loss in boost. I have logs from 45 ambient all the way up to 85 ambient and this holds pretty true.

...and that I see about 1 psi increase in boost when I spray the 100 shot. I'm guessing it cools the air, which makes it denser, which allows more room for the blower to pack more air in.

[dan0617]

Wow nobody interested in test results? Thought for sure this IAT testing would spark some interest.