[JSH]

So I'm in the process of routing cooler air to the TB by doing the ram jet snorkel, removing rain/snow backing, and improving the air let areas.

I was checking engine compartment temps as I always do and noticed that the outside face of the Big Gulp nearest the header gets to 115F. The inside face nearest the filter reaches 100F and the edge of the filter reaches 85-90F, etc., whereas the headlight side of the filter was nearer to ambient. So, I covered the outside of BG with DEI heat shield.

The BG also did not fit the body panel or hood well, and there were gaps between the BG's pieces, so, I filled all those gaps with insulation. The BG surfaces now run much closer to ambient. I can already see improvement in IAT and MAT. The snorkel and headlight area work is next week.

The point is, I was surprised that mine needed this rework. Your CAI also might not be as efficient as it could be.

[Joshinator99]

Originally Posted by JSH

So I'm in the process of routing cooler air to the TB by doing the ram jet snorkel, removing rain/snow backing, and improving the air let areas.

I was checking engine compartment temps as I always do and noticed that the outside face of the Big Gulp nearest the header gets to 115F. The inside face nearest the filter reaches 100F and the edge of the filter reaches 85-90F, etc., whereas the headlight side of the filter was nearer to ambient. So, I covered the outside of BG with DEI heat shield.

The BG also did not fit the body panel or hood well, and there were gaps between the BG's pieces, so, I filled all those gaps with insulation. The BG surfaces now run much closer to ambient. I can already see improvement in IAT and MAT. The snorkel and headlight area work is next week.

The point is, I was surprised that mine needed this rework. Your CAI also might not be as efficient as it could be.

At power levels that typically go hand-in-hand with Big Gulp installations, the airflow is much more important than IATs are. That air is compressed and is significantly hotter leaving the rotor pack (Boyle’s Gas Law), then goes through an air-to-water intercooler which removes a large amount of temperature, probably 60-80 degrees or more (maybe TooHighPSI will chime in with his experience). Five or ten degrees on the IAT inlet is trivial. The much bigger issue is the lack of airflow to the filter area at big horsepower levels. I actually removed the BG insulation strips from mine and gained nearly a full MPH on back to back runs at the strip. I’ll be coming up with something to get serious airflow to the filter this winter…the BG setup is a hold up at my power level. Again, at 700-800 WHP it’s not a problem, but as you approach and exceed 1K WHP, the BG needs help. Just my humble opinion of course.

[Z OH 6]

Originally Posted by Joshinator99

At power levels that typically go hand-in-hand with Big Gulp installations, the airflow is much more important than IATs are. That air is compressed and is significantly hotter leaving the rotor pack (Boyle’s Gas Law), then goes through an air-to-water intercooler which removes a large amount of temperature, probably 60-80 degrees or more (maybe TooHighPSI will chime in with his experience). Five or ten degrees on the IAT inlet is trivial. The much bigger issue is the lack of airflow to the filter area at big horsepower levels. I actually removed the BG insulation strips from mine and gained nearly a full MPH on back to back runs at the strip. I’ll be coming up with something to get serious airflow to the filter this winter…the BG setup is a hold up at my power level. Again, at 700-800 WHP it’s not a problem, but as you approach and exceed 1K WHP, the BG needs help. Just my humble opinion of course.

100% agree.

[Joshinator99]

Originally Posted by Z OH 6

100% agree.

[JSH]

Originally Posted by Joshinator99

At power levels that typically go hand-in-hand with Big Gulp installations, the airflow is much more important than IATs

Did you read the part where I'm doing ram air snorkel and adding additional areas of air flow next week? We're saying the same thing. CAI is just one part.

[Z OH 6]

Originally Posted by JSH

Did you read the part where I'm doing ram air snorkel and adding additional areas of air flow next week? We're saying the same thing. CAI is just one part.

It won't make any difference though.

[Joshinator99]

Originally Posted by JSH

Did you read the part where I'm doing ram air snorkel and adding additional areas of air flow next week? We're saying the same thing. CAI is just one part.

Yeah, I wouldn’t have bothered adding additional insulation to fill gaps as that filter “box” area is starved for air IMO. If you’re adding additional airflow to the area that won’t hurt. That said…

Originally Posted by Z OH 6

It won't make any difference though.

…this is a serious possibility. I question the air filter size for two reasons:
1. Pray nets 35 WHP on a 930 WHP Camaro with simply removing the filter and adding a bell mouth.
2. I just put a nice CF Corsa CAI on my wife’s new Mustang GT and the filter they provide was bigger and better designed than the filter on my BG! My wife’s car needs 48 lbs/min of airflow…. I need 123 lbs/min of airflow… WTF lol

So couple questionable filter size with a “box” area that’s choked for airflow and I think it helps explain why cars that dyno big numbers often struggle to get drag strip performance that lines up. I noticed Jason Leiva’s car does not run the heat shield at all! So it’s pulling in “hot” engine bay air…and trapping 173 MPH. Lesson learned!

[Z OH 6]

Originally Posted by Joshinator99

Yeah, I wouldn’t have bothered adding additional insulation to fill gaps as that filter “box” area is starved for air IMO. If you’re adding additional airflow to the area that won’t hurt. That said…



…this is a serious possibility. I question the air filter size for two reasons:
1. Pray nets 35 WHP on a 930 WHP Camaro with simply removing the filter and adding a bell mouth.
2. I just put a nice CF Corsa CAI on my wife’s new Mustang GT and the filter they provide was bigger and better designed than the filter on my BG! My wife’s car needs 48 lbs/min of airflow…. I need 123 lbs/min of airflow… WTF lol

So couple questionable filter size with a “box” area that’s choked for airflow and I think it helps explain why cars that dyno big numbers often struggle to get drag strip performance that lines up. I noticed Jason Leiva’s car does not run the heat shield at all! So it’s pulling in “hot” engine bay air…and trapping 173 MPH. Lesson learned!

Agreed, total air flow trumps all on the incoming side and when it's comes to "ram air", you're not force feeding the engine any more air than it can pull in on its own. You can create a positive pressure in the air box but that matters little when the engine is only going to consume what it can use regardless of how much is available. At the end of the day, its always about creating the least amount of restriction but I just don't believe any ram air design is going to help enough to matter. When the quickest cars out there aren't doing it when every tenth matters, thats says enough for me about whether it's a waste of time or not.

[JSH]

Originally Posted by Joshinator99

If you’re adding additional airflow to the area that won’t hurt...

... removing the filter and adding a bell mouth.

I'm adding more air and cooler air to the TB. This has to add some power. As you know, at a constant altitude, hp increases as air temp decreases.

I have a bell mouth which I plan to use at the track so I can determine if it alone helps.

My goal is to run 8.9x but all the big hp gains have been made. The accumulation of a bunch of little gains should help me get there. That's why I'm doing them. Plus, I enjoy it.

[laynlo15]

Good write up.

[ZL1Atlanta]

I love the discussions on if RotoFab works and the importance of shielding filters, etc., all while we have been the quickest and fastest PD blown 6th gen for a couple years now doing this.

We did recently remove the headlight. I have no data to say if it helped, but we also just replaced the pictured intake with a larger 3D printed one with a larger bell mouth and picked up 1.5 psi even in 3300 DA.

[JSH]

Originally Posted by ZL1Atlanta

I love the discussions on if RotoFab works and the importance of shielding filters, etc., all while we have been the quickest and fastest PD blown 6th gen for a couple years now doing this.

We did recently remove the headlight. I have no data to say if it helped, but we also just replaced the pictured intake with a larger 3D printed one with a larger bell mouth and picked up 1.5 psi even in 3300 DA.

So my big gulp has a 6 in inlet and I know of bellmouth's for that OD but yours looks larger than 6 in.?

[ZL1Atlanta]

Originally Posted by JSH

So my big gulp has a 6 in inlet and I know of bellmouth's for that OD but yours looks larger than 6 in.?

The inside diameter of that bell mouth and pipe is just 4.5".

[JSH]

Originally Posted by ZL1Atlanta

The inside diameter of that bell mouth and pipe is just 4.5".

How do you feel about running without an air filter? The dragonflies in Georgia can be huge!