Super Heating Air Charge?

[DA BIG ONE]

At what PSI boost will a GM-8 start super heating the aircharge?

[john8662]

IIRC, I believe that anything under 12 psi is acceptable, above that a charge air cooler is in order.

[DA BIG ONE]

Originally posted by john8662:
IIRC, I believe that anything under 12 psi is acceptable, above that a charge air cooler is in order. Understanding an charge air cooler is need for above 12psi, do you know at what pressures the GM-8 would start superheating the charge? I'm asking this to eliminate the boost levels (18+, w/spikes of 22+ @ WOT) I run as a problem.

I see many who run 20 psi but no data on limits of the GM-8 but most will say its the better of all the GM turbos offered on the 6.5td.

Then there is the question of what cfm this GM-8 turbo is capable of pumping out.

[rjschoolcraft]

That depends on a lot of things. On an 85F day, 8 psi (by calculation) will be about 200F. 18 psi will be about 310F and 22 psi will be over 340F.

[Hubert]

I am interested in this answer. A little explanation of theory and principle.

I followed the compression ratio explanation in dvldg's post about why lower compression is better and would like something similar.

I understand as ambient temp rises so does IAT. As boost rises so does IAT. As IAT rises gasses are less dense so you loose effeciency etc.

In a mild increase but higher than stock boost setup say around 10-12 psi no IC.

Why does higher IAT cause too much engine heat?

Is it that the hot air charge heats the intake manifold, intake valve, piston, and top of motor so that its hot in all four engine cycles or is it that if intake air charge is already hot that compression stroke heats it excessively?

I think its that the IC cools boosted air back down so it can somewhat air cool the top of the motor. Or is it simply it does not add additional heat to be removed by radiator.

OLD news but from RJ's post I'll guess at 6psi boost IAT would be somewhere abour 180F then add combustion heat and thats a lot of heat to be removed (with coolant and radiator) hence the 6.5's weakest point.

It makes me mad GM did not add an IC!

[TurboDiverArt]

Originally posted by Hubert:
I understand as ambient temp rises so does IAT. As boost rises so does IAT. As IAT rises gasses are less dense so you loose effeciency etc.

In a mild increase but higher than stock boost setup say around 10-12 psi no IC.

Why does higher IAT cause too much engine heat?

Is it that the hot air charge heats the intake manifold, intake valve, piston, and top of motor so that its hot in all four engine cycles or is it that if intake air charge is already hot that compression stroke heats it excessively?

I think its that the IC cools boosted air back down so it can somewhat air cool the top of the motor. Or is it simply it does not add additional heat to be removed by radiator.

OLD news but from RJ's post I'll guess at 6psi boost IAT would be somewhere abour 180F then add combustion heat and thats a lot of heat to be removed (with coolant and radiator) hence the 6.5's weakest point.

It makes me mad GM did not add an IC! I would say a combination of all the above. Hotter IAT means less power as you have less O2 in the combustion process. Additionally, hotter air charge means you

[DA BIG ONE]

Originally posted by TurboDiverArt:
</font><blockquote>quote:</font><hr />Originally posted by Hubert:
[b] I understand as ambient temp rises so does IAT. As boost rises so does IAT. As IAT rises gasses are less dense so you loose effeciency etc.

In a mild increase but higher than stock boost setup say around 10-12 psi no IC.

Why does higher IAT cause too much engine heat?

Is it that the hot air charge heats the intake manifold, intake valve, piston, and top of motor so that its hot in all four engine cycles or is it that if intake air charge is already hot that compression stroke heats it excessively?

I think its that the IC cools boosted air back down so it can somewhat air cool the top of the motor. Or is it simply it does not add additional heat to be removed by radiator.

OLD news but from RJ's post I'll guess at 6psi boost IAT would be somewhere abour 180F then add combustion heat and thats a lot of heat to be removed (with coolant and radiator) hence the 6.5's weakest point.

It makes me mad GM did not add an IC! I would say a combination of all the above. Hotter IAT means less power as you have less O2 in the combustion process. Additionally, hotter air charge means you

[DA BIG ONE]

I have installed Heaths WI post IC but weather changed to cooler to 74 deg (20 deg drop)w/heavy rains.

I have the WI set to deliver max water, so we will see the changes soon. I'm using pressure to trigger now, then will switch to temp to trigger system only when needed.

[Barry Nave]

Did you have one of Biils WI laying around? I see he no longer offers this.

[JTodd]

I think it has been covered before, but lifting the back edge of the hood will be an air intake not exhaust. There is a high pressure area at the base of the windshield, so air will not exit there. Is anyone using a cowl induction hood on a 6.5? with two sources of underhood air (grill and cowl) is there a reduction in the air flow through the radiator? Raising the rear of the hood may actually add to the heat issues instead of helping.

[Barry Nave]

Using a heat gun, I've notice under hood temps to be what comes from the radiator. In town driving,mostly stop and go with AC the temps will be higher but not bad. A true open hood scoop would be one way. NASCAR hood scoop are on with the opening facing to the rear where the low psi area is when flowing over the scoop.
So I think one could use a hood scoop in this matter also though water could still be a issue.

[DA BIG ONE]

Originally posted by JTodd:
I think it has been covered before, but lifting the back edge of the hood will be an air intake not exhaust. There is a high pressure area at the base of the windshield, so air will not exit there. Is anyone using a cowl induction hood on a 6.5? with two sources of underhood air (grill and cowl) is there a reduction in the air flow through the radiator? Raising the rear of the hood may actually add to the heat issues instead of helping. JT: Thanks for this input, I totally forgot about cowl pressure.
Thanks.

[Kennedy]

Adding a simple deflector (scoop) likemy IC's have will help the little IC out a bunch as well...

[DA BIG ONE]

Originally posted by kennedy:
Adding a simple deflector (scoop) likemy IC's have will help the little IC out a bunch as well... I'll look into installing one, you sell the scoop?
Thanks

[TurboDiverArt]

Originally posted by DA BIG ONE:
I'm thinking I need to maybe lift back edge of hood to let some of that heat escape, the old fashion way using washers to lift it. [/QB]Big One,

Thanks, I like the collection too. I've had a number of different ones in the past but these are the ones I've kept over the years. I'm actually going to get rid of the street GN, breaks my heart! I spend too much money on the race GN. Shame, original owner, 18,500 miles, garage kept, etc. Oh well, need more money to go faster...

The old trick to under hood temps is to remove the rear hood gasket. I don't remember if our trucks have them. If is does, removing this will allow for a good half inch gap. Only down side is that your outside vent will now smell a little of engine smells.

Art.

[DA BIG ONE]

Originally posted by Bnave95:
Did you have one of Biils WI laying around? I see he no longer offers this. Yep, however it only has a 30psi pump...

[Barry Nave]

I built my WI back in 2001-2002 when this use to be a big subject here on the Forums. Back when Steak Sluch (A-something :rolleyes: ) would E-mail me all the time how I came up with the system.
He now sells,Got a Pat. on it (A** Hole)
Spent many years with different mist noozle,pumps,flow rate's to see just how much water was needed and what effect did it have on the turbo blades. Pitting to date is very mimimul(SP). Though leading edge of blades is not as sharp as once was. MC-Master Carr has the nozzel and I run with a 60psi RV pump. Boost control set to engage @8psi running to a relay for the pump with a radio shack lamp mounted in dash when boost control comes on.Also a dash mounted switch.
I don't use much water. I run Wind Shield washer fluid (doller store, $1 Gal.) And then mix 50/50 Denature alochol.
Once water ingages the diesel rattles a bit more at lower boost(talk about power) but goes away at 10psi and boost max is set to 12psi.
IAT Drops slowly when used full duty.
See my IAT gauge is just a Head Temp unit mounted just after the bend,after factory IAT.
I'll see the intake manfold go to 200* @10psi with air temps @ 85* or better. Once water is added then it drops to 140*. That as low as the meter goes. Back then it was hard to fine a true IAT set up and even now it is still costly.
I know it works. Thats what matters to me.
My Water is mainly set up for go power :D
I do have pic's on Sony ImageStation that use to be in my Sig. I'll try adding it again though I have problems with others getting in to see the Album. Wants others to ask, Member number :confused:
For the members that do use the Sony ImageStation,maybe you can help me out to allow others to see the pic's. It's been yearssss sence I done anything with this site but they are still there.
Good-Day ;)
Up Date profile,Show that there is no Album :confused: OK,update. Seems I need to Renew. Ran out 9/15/2005
Another Edit :D
For those who might want to see Pic's I can E-mail them.

[ 10-07-2005, 02:47 AM: Message edited by: Bnave95 ]

[TurboDiverArt]

Originally posted by Bnave95:
Another Edit :D
For those who might want to see Pic's I can E-mail them. I'd like to see them. Can you email them to me at TurboDiverArt@Yahoo.com?

How big is your tank and where is it mounted? I

[Barry Nave]

If I don't ask my wife to help,I get lost :rolleyes:
She will help though. The tank is in the bed along side and in front of wheel well. Came from JC Whitley size is 24" long,6" wide and 18" high.
15gal. Needs a solenoid to fell to the top or water will bleed in to turbo.
this I don't have but can still get 5gal. in.
Thats what I need,another free sight to post.