Nice, B! Man you keep pushing the envelope of the capability of our platform: 275 - 314 ft lbs on tap 4k to redline.

 

Cheers Curtis . Looking back and comparing with old logs I can see power/torque in the 4500 to 7500 range is identical so this manifold is indeed 400whp capable. Where I see improvement is from the 2500-4500 range and the 7500-8000 range . The low rpm improvement from spoolup and the high rpm (after I cut boost) due to the inability of WG to cut as much boost.
All in all ....it's definitely a quicker car now.

 

Brettus

What is your opinion of the exhaust porting work in this video? Would it significantly help the flow in a turbo set up? Additionally around the 6 min mark he discusses a cause for a the early (low mileage) failures. Could this be an accurate failure reason?


This shop is in my area and are known for quality work.

 

I think it would do very little as it doesn't really make the port flow better ...just open earlier which would result in a loss at low rpm and maybe a very small gain at high rpm. Although I have found benefit in doing a mod like that to the outer ports only. Helps with spoolup.It does nothing to address the port timing issue I talk about in the 450 thread.

Re the failure method ..yeah totally . I always smooth out that area he mentions for that very reason.

 

Thanks for the feedback. Thinking about it more later, I started to wonder if the area between the exhaust flow and coolant jacket would start to develop cracks and leak after the pressure and temperature cycles of a FI system. Figured that was dependent on how much material was actually removed but something that was possible if it was too thin.

 

Quite possible ..... there isn't much material at all to work with there. I generally port it at 45 degrees by about 4mm which just takes the corner off..... if you know what I mean. That keeps it at approx. 4mm from water to surface.

 

Came across something interesting the other day . Mazda uses this block off piece to block off and disable the VDI on 6 port auto S2 models.
Will use this in my LIM next time I'm in there.

 

Thats actually quite interesting...

I've never seen that before.

Travis

 

Even more interesting is the little trick a guy local to me is doing atm. Taking S2 5 speed and S2 auto and converting them from 7500 slugs to 9000 rpm screamers. In the case of the 5 speed all that was required was a software change! The auto had a manual fitted plus the software change.

 

I do know the 5 SPD manual is boasted as a more robust transmission and the optimal trans for an REW swap for most anyway.

I love the reverse placement of the R3 Trans personally.. It was almost enough to make me swap one in...

Dont discount backyard mechanics , they can surprise you

Travis

 

I dont get why? Then again, I did not know that they made 6 port with auto, guess I've been sleeping in the S2 development....

Did they stop producing 4 port, but then partially strangled a 6 port to be able to use an auto trans in it?

 

Basically they did exactly that . They also made an S2 5 speed 6 port and strangled that as well for the sole reason of making sure the 6 speed was the premium high power product. So if you get a 5 speed manual S2 with a 7500 redline ....all you have to do is put a VDI back in the hole , adjust the software and VOILA ...9000 rpm redline with same power as the 6 speed.

 

Did they reduce power in the S2 AT to reduce torque delivered to the transmission to keep it from failing?

 

No ...nothing to do with torque and everything to do with rpm.

 

Putting it on the dyno tomorrow

 

How many kms/miles are on your short block?
Looking forward to the dyno results.

 

Todays dyno . Pretty happy with this . Didn't want to push it any further with the 0.83 housing as emap was getting up there. 405whp at 14.5psi

 

very nice Brett

 

Engine has about 20,000kms on it plus 5 or so track days.

 

80% torque just above 3500RPM on a almost 8000RPM engine. And flat all the way up.

Very impressed, indeed....

 

Thanks AAaF , I do have a higher redline than what is shown ....we just stopped it early as I cut boost there anyway. I find the perceptible drop in power pretty handy actually for gear shift timing.

I really want to try the new Garrett G30-660 ..... pretty sure it would improve both ends of the power band even more.

 

didnt know they made a s2 5 speed

 

https://www.rx8club.com/series-i-maj...2/#post4907263
.

 

Wow only 170 hp / 155 ft-lbs is quoted there for the S2 high power. Has anyone ever dynoed a stock S2 (couldn't find it by searching RX8club)?

 

170Kw not 170hp