How fast on a stock air box?

[INTMD8]

Just curious what the fastest people have been on a stock air box?

I'm running two 85 GN air boxes on my twin turbo Chevelle, at 10psi boost, 650rwhp, 10.5 @130mph, 3940lb raceweight the car is barely picking up anything with more boost.

I plan to try some open element filters but was curious how fast/how much power has been made with the stock unit. Thanks.

 

[DCVING 6]

Just curious what the fastest people have been on a stock air box?

I'm running two 85 GN air boxes on my twin turbo Chevelle, at 10psi boost, 650rwhp, 10.5 @130mph, 3940lb raceweight the car is barely picking up anything with more boost.

I plan to try some open element filters but was curious how fast/how much power has been made with the stock unit. Thanks.

Turbos out of steam at that level?

 

[A2000RICH]

Just curious what the fastest people have been on a stock air box?

I'm running two 85 GN air boxes on my twin turbo Chevelle, at 10psi boost, 650rwhp, 10.5 @130mph, 3940lb raceweight the car is barely picking up anything with more boost.

I plan to try some open element filters but was curious how fast/how much power has been made with the stock unit. Thanks.

I recently saw red armstrong run a 11:09 at Bowling Green with a bone stock 87 air box with a 3500 lb car.......RC

 

[bison]

Just curious what the fastest people have been on a stock air box?

I'm running two 85 GN air boxes on my twin turbo Chevelle, at 10psi boost, 650rwhp, 10.5 @130mph, 3940lb raceweight the car is barely picking up anything with more boost.

I plan to try some open element filters but was curious how fast/how much power has been made with the stock unit. Thanks.

May not be a good comparison but i only picked up 6 whp by removing the factory 86-87 MAF in an application where i was getting around 475whp with it on there. You would probably have a quicker spoolup up and it would be easier for the compressor to make more boost but likely wont see much power with the change without more boost. Id bet its less than 15whp. Be sure to back off the boost because if there is a big inlet restriction removing it will cause a big increase in boost. I was hard pressed to get over 27psi with the stock MAF and good air then i promptly buried a 35psi guage the first time i hit it without the MAF there.

 

[INTMD8]

Turbos out of steam at that level?

No, one of the stock GN turbos was dying so I replaced them with a pair of TA5557's.

The 86/87 air boxes look the same except the snorkel is much shorter, not sure how much difference there would be in flow.

The car also has the cast elbows (ported) going into 2.5 downpipes. I'm sure that's not ideal but I would really prefer not to change those.

 

[INTMD8]

To those interested this is 2 stock 87 GN turbos at 9psi vs TA5557's at 10psi. (minimum boost possible with actuators adjusted with 1/2 turbo preload).

 

[Onalky87]

the ta5557s make some impressive TQ over the stockers...very interesting thanx for posting

 

[A2000RICH]

No, one of the stock GN turbos was dying so I replaced them with a pair of TA5557's.

The 86/87 air boxes look the same except the snorkel is much shorter, not sure how much difference there would be in flow.

The car also has the cast elbows (ported) going into 2.5 downpipes. I'm sure that's not ideal but I would really prefer not to change those.

i have never flowed a 84/85 box -------i know it has a longer "snout/snorkle" than the 86/87 but believe it or not the 86/87 box actually flows quite a bit better with the plastic snout in place...........RC

 

[INTMD8]

Again, to those that are interested.

Last time on the dyno, first pull I let it get to 175deg coolant temp then made a pull. It made 616rwhp at 12psi and 17deg timing.

(I just looked at the data log for the 649rwhp run and it was 10.7psi, 20deg timing and had ice in the intercooler tank). It seemed like with more timing it had a lower base boost from cooler egt.

Anyway, tonight I had no ice so I set the timing back down to 17 deg, let the car get to 175 deg and made a pull (the same way I made the 616rwhp run) and the car made 666rwhp at 12psi 17deg timing.

So it seems to have picked up 50rwhp by disconnecting the stock air boxes and running open inlet bells.

At this point I plan to fabricate some new air boxes, probably being fed by air scoops under the bumper that was optional on late 60's 442's.

Also need to install larger wastegate pucks, if possible in the stock cast elbows as I would like to get base boost down to around 8psi if I can.