Quote:
Originally Posted by Modshack
There is a timing pull and you'll naturally heat soak sitting on a dyno table...
It's not necessarily water related though. Your fans trigger at 212 dgrees and shut off at 202 so this is relatively well conrolled when sitting. On the road,temps will run around 182. Most of it (timing pull) is coming from elevated IAT (intake air) temps. I monitor both IAT's and water temps full time on my Scangauge. I've also posted graphs here showing the timing pull on Corvettes when the IAT's elevate. It's much more significant with IAT's compared to water temps. It's not unusual to see IAT's go as high as 150 degrees on the 370 when heat soaking. As close to ambient is where you want to be, which is why the injen and stillen G3 work as well as they do...They pull air from outside the engine bay. The stock system does too for that matter. None of this design is very effective on a dyno as ther's just not enough air flow. This is one reason I designed the Fang vent system to get cool air to the intake. My temps run only 5-10 degrees over ambient when rolling for minimal timing changes. Stop in traffic and the IAT's elevate pretty quickly which is why the car feels sluggish in these condidtions. Mine will come back down virtually immediately as soon as cool air starts getting fed to the intakes. IAT's are genrated at the MAF just upstream of the airbox.
Cooler is always better, but a cooler Water temp won't necessarlily change the IAT problem which IMO is the area that needs to be addressed..
I've played with this on both my previous Corvette and Audi TT and designed systems and insulated airboxes to address it. Finding ways to reduce IAT's worked nicely on both as it has on my 370..
|
Think we have a fair amount of parallel thinking going on here. Here is how I lowered the intake temps on my Corvette. Ram Air intake with a sheet metal intake.
Ram Air Intake picture by dennylmclain - Photobucket
Sheet Metal Intake picture by dennylmclain - Photobucket
This is what I've done so far to lower them on the 370:
Heat Barrier on Gen 3 intake picture by dennylmclain - Photobucket
Heat barrier in engine bay picture by dennylmclain - Photobucket
Basically two layers of thermal barrier wrap with four layers over the MAF sensors in addition to cutting a center hole in the Styrofoam bumper to see if that would deliver more air to the K+N filters.
Looks Ghetto but like you, I've been monitoring my intake temps and yesterday when starting the car cold in 80 degree ambient weather and just driving, the intake temps were 8 degrees over ambient going down to six degrees when the throttle was applied. Really just now trying to get down to the nitty gritty to figure out what the cars like and don't like. Going to monitor water temps, oil temps and intake temps to see if I could figure some consistency.
Bought the tubing to duct air better to the filters and tried to do it Thursday, but just wasn't happy with the routing and securing it when putting the front fascia back on the car. Was in bed this morning thinking about ways to do a true ram air system for the car. I'll keep playing with it to see what happens.
Big believer in dyno time and also a big believer in what I would call "pragmatic power" which doesn't necessarily show on the dyno. Usually dyno pulls are made under the best condition possible which isn't what you encounter in every day driving.
For every 1 degree of air intake reduction you gain 1 percent in hp and if you can lower that during real world driving, you struck oil in my opinion.
Nice thinking and nice work!