A buddy of mine, and I are looking at doing a dyno comparison of a 4 port N/A with:

-S5 TII Intake
-S6 With Adapter
-S6 Without Adapter

I am hoping someone has an adapter with that they are stashing away for future use and that I can borrow it to do the test with. I will cover shipping of course.

Any information gathered will be posted in this section for the benefit of everyone here, and the tests will be done on the same day with the car remaining on the dyno.

 

I would be very interested to see what the result would be.

 

I am sure you would be, but so far there is no FD UIM spacer on the market.

 

There are FD UIM spacers. I will find the link.

 

I'll be watching this as well, as I somehow got it in my head to see what an FD or 13B-RE upper could do for me.

 

^ Yeah. And the only dyno I have ever seen that compares the two is kinda suspect as there is no boost measurement.

As it stands, no one has stepped up to let me borrow one. And I am not sure how much the spacer are but none are available at the moment.

 

Since the secondary runners don't line up directly, any spacer will create a short sharp direction change which will hurt flow a bit on the FD setup which will affect your results. it's not much but it's enough to matter. The proper way to do it would be to modify a lower manifold to match it. This isn't a direct upper manifold swap anymore but is the only fair way to compare them.

 

That's the plan.

In fact that was the original plan, I just thought throwing in another test with a spacer would be quick, easy, interesting, and will only provide more data.

 

It would definitely provide data that shows what results people could expect if they get too lazy to do it properly! I am curious to see what the results will be as the FD manifold uses smaller runners but larger throttleplates which is very contradictory.

 

I was curious to the spacer in regards to it adding length to the runners.

From what the FD RX-7 Book said, the Cosmo 13B-REW was designed for mid range power where the FD was designed for top end power.

 

An FD flange has been cut, preliminary schedule is to do the test early April. We shall see.

So far I have had no luck in sourcing a cheap FC to FD spacer, so that may be left out.

 

Okay, the testing date has come and pass.

And like most car related things something got in the way and the dyno session has been postponed.

The good news is I sourced a S5-S5 Spacer, but no S5-S6 Adapter.

 

so....

 

A while back I did a dyno run of a full FD upper and lower intake, vs. the RE upper and lower intake. The FD did not provide any more torque, and also fell off sooner vs. the RE. The fd lost over 20rwhp if I remember correctly. Personally I feel the FD is all wrong for n/a. The FC and RE are much shorter, and still make the torque while giving top end. If the FC could use the FD throttle body, I would put lots of money on the FC wining the dyno run. Get your butt going on the pulls! lol

 

ncfc3s, ....yeah. Basically the person I am doing this with is getting his degree and always has cars in his shop and so never has time.

This is still something we both want to do but finding time is turning out to be the normal problem. My car probably won't be on the road in the winter so I wouldn't expect anything for some time now.

 

If you do a TII block, let me know in advance if you want to do some experimentation. I've got this "special" N/A intake manifold.

Never compared it on a dyno vs. the TII manifold, but I had to add a lot more fuel everywhere to keep the same AFR. Looks like the 4-port likes the dynamic ram tuning as much as the 6-port does.

I'm not going to be using it anytime soon, not only did I destroy my TII end housings (no more 4 port for me) but I've gone back to a GSL-SE block after killing the bearings in a 6-port. I'm taking no chances with overrevving this one, I've blocked off the aux ports entirely. Take THAT, evil horsepower!

 

Lol

 

and I want to compare your results to my carb'd 6pt NA

I just need to get to the dyno soon.

 

holy crap! what happened ... how (circumstances) ... and when?

 

Aw man, that was a long time ago. I don't know how many engines ago that was

Combination of a lot of things - I had oil pressure problems from the start. Replacing the main bearings brought pressure up to "barely acceptable" and I ran with it, but the rotor bearings were also destroyed. I had the engine apart (weekend driveway reseal, blew a coolant seal at a 105+degF rallycross where I don't think the coolant ever got down to 180-190 between runs) and noticed some corner springs that didn't "pop" like the other ten, but as I had to have the engine together ASAP, I just rolled with it as they still popped up about .015". Rear rotor, rear face...

Ran engine a while and after another rallycross it basically began choking on its own oil. That was also the one where it wouldn't build oil pressure until it'd been running a couple seconds. Pulled it apart and found a trashed E-shaft, wrecked rotor bearings, all corner springs on the rear rotor flattened, oil rings on the rear rotor were ground flush, and the rotor wore huge grooves (through the hardening) in the rear end housing.

The early-opening 6-port lasted four days. Haven't done postmortem yet but it looks like the side seals didn't self-destruct like I'd feared. The oil is absolutely funk-nasty with black sludge, but that engine always had huge oil pressure. I'm thinking now that the Atkins apex seals wore the spring pad area so deeply that they don't actually apply tension anymore. When I popped the engine together, a couple of them wouldn't hold any tension at all on the small spring until the long spring was pushed through.

"New" engine is a $100 GSL-SE block that was severely corroded internally and one of the rotor housings has a chunk missing from the chrome about half the diameter of a dime. So I pretty much left the ports alone and plugged the aux sleeves to maybe keep me from overrevving it. and I duplicated my TII block's half bridge eyebrows, except I didn't go as high up, and I went out to the coolant seal groove and did a big relief in the rotor housings

One of these days I'll figure out what has been killing these engines. Funny that my engine problems only really started when I installed the Racing Beat crank pulley.