skinny z

I've seen several posts regarding cutting open a TPI air intake assembly and modifying it for increased flow.
Plenty of pictures of finished products but does anyone have a picture with the two halves split apart? I'd like to see what I'm getting in to before I start carving into one.
I'm thinking of adapting the TPI inlet to a sealed 14" filter case.
Sort of a hybrid.
1bad91Z has an excellent thread.
https://www.thirdgen.org/forums/tpi/...pi-camaro.html
I see there are pictures of the cut up unit there. Anyone else?

rusty vango

changing the amount of air that the MAF "sees" .assuming you don't have a SD car.can play hell with the ECM as it tryes to adjust for it. you may need a tune to make it work

skinny z

No fuel injection here however tuning a carb for the new cooler denser air isn't much different. What I'll be looking forward to is a somewhat more stable idle as the under hood air temps won't play so much into the AFRs.



This more or less my intended approach however I'd use the TPI inlet modified to a 4" pipe to lead into a sealed filter case. The one in the pic above looks to be a Ram Air Box piece.
What I don't know if any or all of this would fit under an aftermarket 'glass hood.

MoJoe

iTrader: (5)

Isn't that the advantage of the MAF system over SD?
1) You make a modification that allows more airflow. 2) The MAF measures the increased airflow. 3) The ECM compensates by adding the correct amount of additional fuel. 4) More power at WOT and/or better fuel economy at part throttle.

skinny z

Still looking for pictures...
Cut up TPI boxes. Completed projects as in the picture above. Looking for ideas.

I think one of the interesting benefits of going with the TPI intake and a sealed case air filter housing will be that the cowl hood will work as a heat extractor. I can take cool air from in front of the rad (via the TPI intake) and let the hot air out through the cowl opening.
Looks like a win-win.

What I'd like to see are alternatives to the Ram Air Box filter case.



Ram Air Box 14 x 4 filter case.

MoJoe

iTrader: (5)

Getting air from in front of the radiator is a good thing. BUT, thinking you will get air flow out through the cowl appears to be flawed... That discussion is also going on here: ZZ4 and cowl can't vent to high pressure...

The argument is: If cowl inductions "suck in" air due to the high pressure at the base of the windshield, how could you also vent high temperature air from under the hood into the high pressure area?

But since the cowl has to be sealed to the carb/intake, is it a matter of ranking the multiple areas of pressure? ...
Lowest - at carb... at least at WOT, the engine is drawing in air.
Middle - Windshield/cowl is higher than at carb, so can provide cooler external air.
Highest - But, if windshield/cowl pressure is LESS than general underhood pressure, air will flow out from under the unsealed hood into the "high pressure" zone in front of the windshield.

I haven't measured these to state which is true. Perhaps someone with experience and first hand knowledge can comment. Or someone with an unsealed cowl can tape some yarn in the cowl, and see which way it blows when driving.

skinny z

Think about it further...
Where is the pressure the highest? Directly in front of the rad or in front of the windshield? I think it's a safe bet, especially with a laid back windshield like on a 3rd gen, that there's a significant difference in pressure between the two areas. The pressure is most certainly higher at the front of the rad.

Now if you are to seal the carb to the cowl, you eliminate the air pressure differential between the front of the vehicle and the windshiled in terms of air flow. The air being rammed through the rad at 70 mph (and the subsequent pressure that builds up in front of it) passes through it and escapes through whatever route it would take without a cowl. The windshield then acts as the high pressure reservoir for the intake.

I've seen the effects of the open cowl and the way the rain behaves on the windshield when at highway speeds. (My carb is not not sealed to the cowl). There's definitely air moving out from under the hood.

MoJoe

iTrader: (5)

Yup. As I was typing in the first part of my post, I got to thinking more about relative pressures, and posted the second part.

Rear of hood sealed... air flows IN from cowl to carb. (cowl >> carb)
rear of hood unsealed... air flows OUT from underhood to the cowl (underhood >> cowl)

skinny z

There are the detractors of the cowl hood cold air principle and while I've always supported it (NASCAR still uses it) I'm having second thoughts as to how effective it is on the more aerodynamic profiles like a 3rd gen. Obviously, in a perfect world there'd be NO high pressure in front of the windshield as this would reduce the overall efficiency with respect to aerodynamics.
I'm liking the idea (more and more) of pulling air in from the front of the vehicle for the CAI and letting the super-heated air from the rad (arguably 200+ degrees) escape via the open cowl. This would work provided the thinking that the pressure in front of the windshield is less than in front of the car is correct.
I just might tape a few MAP sensors to these spots on my car and run a few tests.

MoJoe

iTrader: (5)

If you have the cowl, just tape some yard, string, etc. near the cowl and see which way it blows.
Without the cowl, pull the weatherstrip at the rear of the hood, and see which way the yarn blows.

skinny z

True enough. Seems to me they used to design F1 cars that way. Still it'd be interesting to know the pressure difference. (However it just occured to me that a MAP sensor wouldn't work as it measures pressure below atmospheric. I'd have to find something that would mesure the actual air pressure above atmospheric.
I'll try the string thing when the spring driving season finally gets here.