how does inlet temp effect BHP

Post Sun May 13, 2007 2:53 pm

Now i know the lower the intake temp to an engine the better but i was just wondering if there was a formula someware that siad on a turbo/supercharged engine if you could lower the intake temp to the Turbo/suopercharger by X degrees C you could expect to see X bhp gain?

reason being i was thinking of cutting a 3" hole in front of the inner wing behind the head light and pipeing my air filter to the area behind the bumper infront of the arch liner? any thougts??

i also thought of swopping one head light for a single motor bike light (of the same size) and using the opening to pipe in the air filter with a shroud like those K&N viper or green cotton "twister" filters but then i would loose the "sleeper" look!

what you think?

Post Mon May 14, 2007 3:29 pm

i also thought of swopping one head light for a single motor bike light (of the same size) and using the opening to pipe in the air filter with a shroud like those K&N viper or green cotton "twister" filters but then i would loose the "sleeper" look!

This what I done to my cab, didnt use the motor bike light but that is a good idea so you get dip and main beam.
As long as you get colder air in it dont matter how you do it.

Post Mon May 14, 2007 4:25 pm

what light did you use then??

i was going to try and make it all legal and have the right light (side, dip, main) even if there not overly bright.

Post Mon May 14, 2007 4:44 pm

what light did you use then??

I didnt

well only the e30 dip beam one

Post Mon May 14, 2007 4:54 pm

the colder the air, the higher the density , the more power to be had.

cold morning on N/A car= fast, summers day, same car, percieved to be slow, the effects are there for all to feel dude

pulling air from the brake ducts is a great idea ! bigger the opening the better

re theheadlights.... swop in a H4 type bulb holder to lowbeam, you'll be sorted, but not legal as lamps MUST be a "matched pair"

*edited, bloody typos !*

Post Mon May 14, 2007 6:23 pm

re theheadlights.... swop in a H4 type bulb holder to lowbeam, you'll be sorted, but not legal as lamps MUST be a "matched pair"

So just do away with both main beams

Post Mon May 14, 2007 6:36 pm

swop in a H4 type bulb holder to lowbeam

How easy would this be to do ?

Post Mon May 14, 2007 7:33 pm

single head lamp E30... that would look f*ckin cool man!!!

Post Mon May 14, 2007 10:28 pm

ive had a little play with this, not got the other light in yet though.

Its one of those larg sub box ports araldidted on, fits sooooo well.

Post Tue May 15, 2007 9:05 am

Thats how I done mine

What motor bike light are you going to use ?
Or are you going to fit the H4 bulb in to the outer bmw light ?

Post Thu May 31, 2007 2:30 am

Post Thu May 31, 2007 8:01 am

Inner wing isn't such a good idea as the air is turbulant there and still spiralling down the side of the car from hitting the front end.

Headlight is a decent place though

I had single headlights on my e28, looked hard. One was for air filter, one was just to make it matched, save some more weight, and generally get more cold air into the engine bay as heat soak was bad in that.

Post Thu May 31, 2007 8:10 am

Re: engine bay cooling. Think you're better off finding ways to get the hot air out of the bay than trying to ram more air in.

Had some great fun on Saturday with high air inlet temps. Due to a not very well thought out filter location (not my design I might add) sucking up air from the rad, we were seeing over 70degrees C!

The poor engine was dying on it's arse, presumably due in part to a lack of oxygen. The air box was too hot to touch too!

As a quick fix, we went to Homobase and bought a flexi duct thing from a tumble drier. Having moved the filter, we covered the duct and air box in adhesive silver foil. Boom, instant 50degree temp drop, engine was a lot keener to do it's thing and it wasn't trying to die on light loads.

Pointless tale and full of anecdotals I know but it was a good illustration of the benefits of cold inlet air.