Has anybody tested the options available to see which one is better than the others? I've seen the RacingBeat and Mazdatrix units, anyone have a secret Aussie or NZ unit they like?

It looks like the stock injection manifold is the choke point at the RPM's we run in EP. The length of the runners is too long for the power band we want.

If nobody has done a test on a flow bench yet, I'd be willing to test whatever I can get in my hands on mine.

 

I don't know of any back to back tests, but mazdatrix is running Webers on thier EP car if that means anything to you.

 

I think Manifolds sold by Mazdatrix are Racing beats. Just like their headers and exhaust and many other parts they sell.
Most of the IDA manifolds are pretty close in performance. To get the most out of them you will have to custome port the runners/manifold.

 

FYI-All the top RX7's in EP are running a Weber. The word I'm getting is the injection gives up as much as 15 HP maybe a couple more. Its all about intake design. The injection is superior through the RPM range up to probably 6500... the range we use is from 6000 up!

Crap I hate carbs.

 

Sounds like you are someone who could use a manifold like mine. The blue graph is a stock s4 intake mani that was ported. The red graph is the custom intake mani I had a friend fab up for me. Mind you the blue graph also had an a/f ratio of 14 or leaner up to 6000rpm. Hints why it looks like I lost power. Both runs were with the same sae correction and the only thing that changed was the intake mani.

 

Twins80s, is that an injection manifold? If I stick with injection I'm stuck with all the stock stuff from the TB to the engine. I can port the manifolds but runner length is the issue not volume.

I've been kicking around doing my own IDA manifold, something that keeps the bend to the engine a little smoother. I need to see how much room I have, check what dies I have for my bender and look at dia tubing would be best for the air I'll be moving.

Nevermind, just saw the thread a few lines down. Nice plenum.

 

Oh didnt know you had to stick with the stock mani if it was injection. Mine is fuel injection built off of a carb manifold. The short runners is a big thing with makeing power up top.

 

Are you limited to downdraft?

 

Not limited to a down draft but going to a side draft you almost end up with the same length intake as the injection. That would be a step backwards, all the problems of the long runners with the added bonus of having to deal with a damn carb!
Tha side draft would be a great street set-up though if you wanted to go carb.

Twins80s, where did you get that simplymaz manifold? I found them in aussie land but could find a stateside dealer. That one looks a lot better than the Racingbeat unit for flow. Of course, if you could tell by looking it would be easy... The flow bench doesn't lie!

 

I actually had it shipped from the land down under. Actually saved a few dollars too!

http://www.tweakit.net/shop/product_...roducts_id=105

 

Drummond makes the best IDA manifold. Needs less grinding to optimize. Mazdatrix fabbed their own IDA manifold for the EP car. Real nice piece of work.

 

Well I've spent the last few days gathering stuff to make my own manifold. I have to wait for some low melt alloy to get to me so I can bend the aluminum tube. Pics to follow and flowbench testing after that. I'm going to see if I can pull my friends racing beat unit off of his car to do some comparison testing.

 

With a little creativity you'd be surprised to learn what a modified stock manifold can actually do!

 

Drummond? never heard and google resulted in nothing. more info wanted!!

 

I'm pretty limited to what I can do to the stock injection manifold but give me some hints!

Here is the rule set: #7 is the killer

3. Stock or permitted alternate downdraft carburetor(s) can
use an adaptor plate and/or a spacer in addition to any
stock spacer, between the carburetor(s) and the intake
manifold. Material for the adaptor plate and spacer is unrestricted.
No adaptor plate or spacer can serve any purpose
other than to space out, or mate the carburetor(s) to the
permitted intake manifold. The adapter or spacer cannot
change the carburetor(s) orientation. Adaptors and spacers
can have a bore larger than the throttle bore of the stock
or permitted alternate carburetor(s). The maximum thickness
for the adapter, spacer, stock spacer or combination
of all is 1.25”. For the purpose of these rules an Isolator is
a spacer.
4. Fuel Injection: All inducted air must pass through the
throttle body and be subject to control by the throttle
butterfly. The stock throttle body casting/housing must
be retained. The inside dimensions of the throttle body
casting/housing and all dimensions of the throttle butterfly
must remain stock. The throttle butterfly shaft must not
be relocated. The outside diameter of the portion of the
throttle butterfly shaft located in the throttle body bore
must be no smaller than stock. The contour of the interface
between the throttle butterfly shaft and the butterfly
must remain stock. The throttle butterfly and any throttle
butterfly to shaft screws/bolts can be attached to the
throttle butterfly shaft by any means including welding
or brazing. Holes or slots can be created in the throttle
butterfly for purposes of idle adjustment only. The number
of injectors must remain stock. The mounting position
and injection point must be stock. The original type of
fuel injection must be maintained (electronic, mechanical,
Bosch CIS, etc.). In all other respects the fuel injection
system is unrestricted.
5. All carburetors must retain the stock method of fuel
distribution. Utilization or modification of a carburetor’s
components to effect an annular discharge configuration
is prohibited.
6. Air cleaners, velocity stacks, air supply ducts and cold air
boxes are unrestricted.
7. The intake manifold may be port matched on the port
mating surface to a depth of no more than one inch. Balance
pipes or tubes on all intake manifolds can be plugged or
restricted. The intake manifold can not otherwise be modified.

 

http://www.awrracing.com/pages/drummond.html

 

So after gathering the goods to build a downdraft manifold the March Fastrack comes out and we are allowed to port the stock manifold now. Looks like I'll keep all the injection plumbing on the car, add a low pressure fuel circuit and test them back to back.