Intake manifolds................what a PITA it has all been. Starting from an out of control internet battle and ending with 2 years of testing just about everything I could get my hands on.
The amount of testing that I have performed over the last two years is borderline obsessive compulsive. I've had intake manifolds on and off my RS so many times I literally wore the threads out in the head.
For those of you that followed all the testing a lott took place. First it was simply dyno testing in the winter of 07-08. Then it went into flow bench testing along with dyno testing during the winter of 08-09 and then we tested some new intakes and re-visited some old ones.
During all this testing we had our dyno re-calibrated which moved our entire power curve to the right (making things appear more laggy than they were before). This threw things off and we had to go back to re-do some testing to get things back into perspective. Then at some point during all the testing I decided to install a set of cams I had custom ground from Crane, this again changed everything. Power rose by 30+ whp with the cam change. More testing followed, some of it was going backwards to baseline again with the cam change as the cams lost some low/mid range.
Unfortunately the exhaust cam on the car failed, this led me to trying to mix-match the Crane intake with an exhaust cam from a different company, this caused HUGE low/mid range losses. I couldn't even stand to drive the laggy POS at that point.
The car has been through a lot of changes with all this testing but I am happy to say that right now the car is by far the best it has ever been. The fattest HP/Torque curve it has ever had, actually enjoyable to drive on the street with enough low/mid range to make me think I can autocross it with the HTA86 on it. It's proven itself running three back-to-back 9.1's at 158 mph at this years shootout in 95 degree heat, with no cool down. To give you an idea of how hot it was and how quickly the car was run on those three runs the coolant temps were at 210 degrees and the intake air temps were at 146 degrees!
During the intake manifold testing we built a few intake manifolds as I felt I was getting a grip on what the car actually wanted and what would work. The very first intake was a winner in the power producing department but a mis-calculation on my part left me with an extremely tight fitment to the firewall. I was happy as hell with the power curve but knew we could do even better.
We built a few that ended up scrapped, some of those parts are here on display in our showroom.
Then we built what was to be our final attempt and also proved to produce the largest average power from 3,000-9,000 rpm of any intake we ever tested.
The stock intake manifold performs the best from idle to 5500 rpm, end of statement, nobody has produced more power than the stock intake in that area.
So when producing an intake that is going to make big power up top I wanted to concentrate on also building one with the LEAST LOSSES down low. I am not building a drag only car and neither are most of you. I wanted an intake that would make great numbers across the entire rpm band of the engine and that's what we ended up with.
Another requirement was to be able to use the stock throttle body and any available intercooler pipes, without cutting or modifying.
The intake we built sits in the stock location as far as the the throttle body is concerned. No changes to i/c pipes are required.
I do not want to go into specifics about plenum volume or runner length because that is the one mistake that I feel everyone is making in their intake manifolds. This is based on MY PERSONAL requirement of the best overall power from 3,000-9,000 rpm.
The BR fabricated intake manifold has provisions for the dipstick to be bolted on and uses the stock or any aftermarket fuel rail. The throttle body flange is 65mm to mate up to modified stock throttle bodies. We do not use tapped holes or a block that you have to drill and tap for boost/vacuum fittings. We have billet aluminum bungs/nipples welded into the intake manifold. This makes it impossible for them to strip or leak. Just push your hoses onto the supplied/installed nipples. There is one located in the back of the plenum for the brake booster, two on the drivers side end under the throttle body for BOV and a MAP sensor or Boost control. On the passenger end there are two more nipples one for fuel pressure and boost or MAP sensor. I can't stand having the fittings in the back of the intake, they are impossible to get to. I can't stand the fittings on the top or front because it makes it look cluttered. The fittings on our intake have been placed where they need to be so they can be used with the shortest hose routing and look clean.
Dyno testing. The intake manifold has been dyno'd now with two different cubic inch engines, 2 liter and 2.1 and has been dyno'd with two different sets of cams, our 272's and the custom set of Crane's. In all testing this intake manifold has out performed every other intake manifold that I have tested. The testing is however not back-to-back. I originally had no intention of selling the intake manifolds. I wanted to build one kick ass part for my own car and that was it. Given the amount of time and effort we have in testing and building the part and the current state of what is needed for go fast parts, I have changed my mind. Providing dyno sheets I can do but in doing so I have to say that much of the testing has spanned over 6 months and I do not have good back to back data with the cars current power curve to compare to say, the stock ported intake. The last time the stock ported intake was on the car the IAT's were 46 degrees. My latest testing was done with IAT's in the 90's. Keep in mind though, the most power was still made even in those temps with our own intake manifold.
Here is a picture of the new intake manifold:
INSTALLED ON THE BISH:
Added optional AN fittings to the intake manifold instead of the billet hose barbs:
These are available now, instock. I'd like this thread to stay where I am putting it so I am not posting pricing here. Shoot me a PM if you are interested.
Thanks for looking.
Nice work dave.
