Let's see how much m20 heads suck.

[digger]

my bad, i would not mismatch parts (unless i was to fit a ported 200 head to a b25 bottom end;)) but that is how i interpreted his post given there has been no 200 head flow numbers

[digger]

We are several tests in ;)

The variance between ports are negligible, extremely close to equal between castings and individual ports

do you mean it is close to equal with the manifold attached?

[digger]

Also, Digger, those numbers are full "I", full sETA and full ETA. Didn't post our findings on mismatched parts.

lol my bad

[ForcedFirebird]

So after almost 100 flow tests and many hours in porting and research the eta manifold ported to match an 885 TB loses 4cfm averaged over all lift values vs the 885 manifold.

If you ported your 885 manifold, you killed the flow. It's already too big.

Now not only did you hurt flow, you decreased velocity.

[Goldfishbowl]

Just an example of 1 test, which was the 2nd to last for the runner and 13 previous modifications lead to this design. It started as a small change to one corner of the port, make it symmetrical, another small change to 1 side, repeat. There was one test after this, with the bump completely removed.

Did this help? Not really.

[ForcedFirebird]

Let's get the results more consistent when testing without a manifold.

It follows the angle of the port entrance, then bell-mouths from there...

[HawaiianE30]

This is awesome, so 885 manifold is fine as is, I'm sure by now you have a best choice for head porting or are the 885 heads pretty good to go stock?

[AlphaE]

FF you continue to provide solid info w a very technical perspective. Love any of the info ive read that you posted, incld this. I just ordered gasket to do my superE to "i" conversion. So this is perfect timing.

Any info on gasket matching the head and intake mani? any benefit to it? i already took the lower humps outta the intake mani, as in the pic above, maybe i shouldnt have done that.. But will the .2 liter increase in motor difference (2.5 vs 2.7) make up for the decrease in velocity, cuz i took some material off, due to the larger volume of air needed.

OR- probably not, but how bout using the SETA intake on w the i cam and TB? dumb idea? youd maintain the velocity and still have the volume needed. It may choke top end though?? How would this match the i cam profile. I think this is still on topic since its about benchflow and manifold/head combos..

PM w any tips/tricks for makin a superE "stroker." we all know its not really a stroker at all....

[ForcedFirebird]

Leave the heads and manifolds alone, all the "ported" stuff we tested either was same as stock or worse. Even if your "ported" head flows the same as stock, you are ruining velocity.

The seta manifold is junk in all aspects. We will prove it eventually, but, from what we have researched so far, the best bet is to use the eta manifold bored to match the "i" throttle body and 885 head. It's just theory based on flow numbers at the moment until we can get on a dyno and prove it, or see if the eta manifold hinders top end performance at all, but think it will be better overall - especially in the lower RPM's.

[AlphaE]

i took the little hump out of the bottom of a i intake rigth where the gasket is.. anyways... Good thing is saw this before i pulled my head...

So your theory is the small diameter of the e intake mantains high velocity at low rpms but wont kill high rpm volume (maybe)? but you have to open the TB and head mating openings?

you have my attention... go on.....

[digger]

my guess is that the longer runners will hurt the topend more than any "restriction". having said that i have not butchered an ETA manifold to know how much smaller the ID is compared to the B25 manifold.

[Varinn]

I'd love to see the potential for bottom end gains on the powerband by using a modified eta manifold. The b25 is fine when you get to the mid range but it's seriously lacking off the line and not nearly as pleasant a daily driver motor as an eta. Gas mileage seems to suffer because of the need to keep the rpm's high or the motor really bogs down under low rpm load. Keep it up Firebird, it's wicked to see legitimate facts.

[digger]

I'd love to see the potential for bottom end gains on the powerband by using a modified eta manifold. The b25 is fine when you get to the mid range but it's seriously lacking off the line and not nearly as pleasant a daily driver motor as an eta. Gas mileage seems to suffer because of the need to keep the rpm's high or the motor really bogs down under low rpm load. Keep it up Firebird, it's wicked to see legitimate facts.

logical thinking says with the smaller capacity a B25-etamanifold wont better an ETA/SETA at the bottom end

[FLG]

How about a ported head on a F/I motor? Let's say 350-400whp I assume there are than gains to be had?

Sent from my Galaxy Nexus using Tapatalk 2

[ForcedFirebird]

logical thinking says with the smaller capacity a B25-etamanifold wont better an ETA/SETA at the bottom end

The cam profiles would be a major limiting factor there.