View Single Post
TurboKraft TurboKraft is offline
Registered User
TurboKraft's Avatar
Join Date: Mar 2005
Location: Phoenix, AZ
Posts: 2,540
Originally Posted by john p View Post
I raced a Kremer 930 in the late 80's and did a lot of dyno work during that time. We found that the original air box made more H P than all of the options available. The Kremer cars came with the original air box so i asume they also did the research and arrived at the same conclusion. Kremers told me they believed it had to do with the cone on the air box above the intake
Had this discussion with Chris from Turbo Kraft ( who i consider the guru on turbo engines bar none in the world ) and he made an interesting comment. He was told that was true but over a period the heat soak on the steel air box affected the intake temp . Good point. This conversation started because I wanted to run the plastic air box with the cone cleaner as to give more space in the engine bay on my Kremer road car ( which I will now do )
Thanks Chris, I hope have not offended you by disclosing our discussion, but he is definitely the go to person

All good!

Yes, a colleague of mine -- whose opinions I respect -- believes that the claimed performance gains from the plastic ("Powerflow"?) air filter housing are only because it does not heat soak.

If this is the case, then we should be able to install one on a CIS 930 next time we have one on the dyno and measure a performance gain, right? Because a stationary chassis dyno is hardly an optimal test condition, with the drivetrain doing 125+mph but the car is stationary so not benefiting from 125mph of high pressure cooling air. The stock filter housing should heat soak and cost us HP while a plastic one will not, right?

Heck, we could also test the engine with a standard filter housing to establish a baseline, and then heat the filter housing with a map-gas torch and see if we start to lose power.

My theory is that it may make a very slight difference on the dyno, but is won't make a flip bit of difference on a Turbo driving down the road. The engine is flooded with high pressure ambient air that I think will overcome any effects of heat soak. You can get considerable changes in engine output (and response) with variances in exhaust and intercooler temperatures, and my bet is that these dwarf any effects from a hot filter housing.

At that point, it's up to the competing designs of the filter housings to generate a measurable performance gain and in past testing I've seen no measurable benefit from the plastic "Powerflow" filter housing. Not on MODE's engine dyno, and not on back-to-back tests on a Dynapack chassis test (average of 3 tests before, 3 tests after). I know the manufacturer made some big claims and sold a lot of them, but the testing was so biased that *anything* would have shown gains. The baseline runs were performed with a tiny Type-1 VW sized filter that was restrictive.

Final thoughts on modified vs. stock filter housing: the stock filter housing has a ~3in air inlet, and a 3" inlet will easily support 600whp. The filter element has surface area comparable to cone filters we've used on engines making over 550whp. I don't see either of these features of the factory filter housing as limitations a CIS 930 engine.
Chris Carroll
TurboKraft, Inc.
Tel. 480.969.0911
email: -
Old 10-12-2017, 11:09 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #10 (permalink)