TweakGames

Hello all.



So first let me start with my past experiences. I have had my 88 GTU for a couple years now I am on my 5th or 6th engine. I started with NA and ended up converting everything to turbo. I am currently running a turbo 6 port high compression doing 184.5 @ 4 psi on stock everything. Sadly I just blew a side seal (75 75 30 compression) and am planning my next (and final) motor.



That being said, I am making plans, and taking apart ALL of my past blown or not blown engines. I have rotors and housings all over the place. The rebuild process looks pretty simple and strait forward. (I also wanted a diy rebuild video).



I have access to almost all parts seeing how I am officially a mazdaspeed member now.



Anyways I am tired of putting in used high milage engines and I have decided to start fresh. I am looking to put down around 400 rwhp safely and daily. When drift season starts again I will be drifting. (please don't hate me because I like to slide around. I do it only at the tracks) The main thing for now though is plans to build it strong and able to handle the turbo I will be installing later. (I have not decided that yet.)



My current plans are this:



FD housings

RX-8 e-shaft

regular rebuild stuff - (OEM apex seals, apex springs, orings, side seals and so on)

Atkins solid side seals

FD side seal springs

T2 primary ports (intermediate plate)

NA secondary + aux port (side plates)

Both with a minor street port

Competition Rotor Bearings

Competition Rear Main Bearing

Pineapple Racing coolant seals

S4 T2 8.5 low compression rotors

Thermal palet mod

Dynamic Balancing from either Pineapple or Atkins

Shimming the oil pressure regulators for just slightly higher oil pressure





That is all I have right now. I know I won't be making power at higher RPM (8500) but I would like to have the ability to bounce the needle off 8500 for a sec in case I need to hold a drift without shifting. Basically I am looking for a build plan where I could go a good 80,000 miles without worry, even after adding enough boost to put down some serious power.



Obviously later down the road a FMIC, meth injection, and fuel upgrades are going to be needed, but I will be running stock turbo, with a haltech until I can save up for a real turbo setup. (also it will help me be nice on the break in period) Right now I am just making plans for the core.



So that is my plan, if you have any recommendations, comments, or helpful information, I will be happy to listen. I know there are some very knowledgeable people on this forum. I hope I have gave enough pre-information for some good feedback.



Thank you, and thanks for everything in advance.

TweakGames

j9fd3s

not bad, if it was mine, id shitcan the 6port end plates, and use turbo ones, sounds like you want a good midrange setup.



i wouldnt use anything atkins, oem is better.



higher oil pressure will give you better rotor cooling, so use the FD regulator



balanced rotating assembly, will be good for 9000+ so it should have no trouble seeing 8500, although you do have to be careful of revlimiters, they can be really harsh, and break stuff. http://www.fc3spro.com/TECH/HOF/K2RD/k2rdhof01.html thats what happens when you bounce it off the rev limiter too long



i like the 8.5 rotors, bigger saftey margin.



only other big thing is cooling

TweakGames

Awesome thanks.



So using the NA 6 ports would only be good for a more powerful top end? Basically like a very large turbo port? I liked the idea of how the aux ports caused back pressure wave. I will need to go s5 plates for sure. Sad day cause I have some good 6 port s4 plates. :\



As far as I know the s4 t2 ECU doesn't have a rev limiter, and even after the haltech I think I would have it set for pretty high. High enough where it would be impossible to hit it by accident. Was all that destruction caused by just bouncing off the rev limited or mainly just because he was trying to maintain such a high rpm for a long period of time? (basically was it the rpm or the rev limiter that killed it?)



I did not think about using the FD oil regulators, thank you for that. And I guess I will go stock side seals.



Anybody else have any comments?



On a different forum they speak of pinning or studding the block. I have researched but havn't got any definitive answers. :\

BLUE TII

You should ditch the 6-port end plates because the NA rotary was about using velocity through the small diameter ports and pressure wave tuning to get the nearly 2psi intake pressure to push a little more charge into the chamber with the late closing 6 ports to get the most chamber fill at atmospheric pressure.



The turbo set up will be all about big flow since you have already achieved pressure above atmospheric.



With a big port on a 4 port you can create a situation that gives you a peaky powerband even with a small turbo. For instance, I get boost literally off idle and full 15psi boost before 3,500 rpm, but power doesn't really come on strong until 5,000 rpm because I have large late closing ports plus a decent exhaust port and power falls off hard at 7,500-8000 rpm because of the small turbo. Everybody at the races say man you gotta ditch that huge drag race turbo...



So, I would suggest a moderate exhaust port and an early opening street port intake that only closes a bit later to keep the scissoring and beveling necessary for sideseal life if you want midrange power to match a small/medium turbo (350-450 hp range).

TweakGames

Ok, thank you very much.



So if I read that correctly you would recommend a good exhaust port and a intake port the opens up earlier. Now I was wondering, since I am going to be using FD housings, aren't the exhaust ports already a little larger then an FC?



Also, since I will have to buy a new intermediate and side plates, (all I have is s4), would you recommend s5 or s6? I wasn't sure if s6 has the same reinforcement on the rear plate like the s5 does.



Boost at idle huh, wow how is the gas milage? 8 mpg? I don't understand why the racers say you should ditch the bigger turbo if you power falls of so hard because of the small turbo? Are they just confused or would it be better for you to have a smaller turbo so you would have power earlier? Wouldn't the power just drop off sooner? What turbo are you running by the way?



By chance could I get a list of what your engines parts consist of Blue and j9fd3s?



Thanks.

TweakGames

Woops. I figured out that if I went s6 primary and secondary ports that I would have to get a FD intake. Although if I did I could run the stock FD twins.

j9fd3s

with the stock gearing and ecu revlimiter, at thunderhill that car was at the 8250 rev limit for something like 20 seconds a lap....



studding the block is valid, but theres no need unless you're making huge hp 450-500+

j9fd3s

we compared the fc and fd housings, and the fd ports arent bigger, but they are a better match to the sleeve, its like its built better



my last t2 was the following.

s4 t2 block

intakes were deburred

exhaust was ported 2mm down, top was cleaned up

s5 turbo

rotors were polished

all new mazda seals and springs etc

s5 turbo@.4bar

80mm RB exhaust

cone intake, but stock tid

680cc secondaries.

light flywheel



the car was really really fin to drive like this, boost was nearly instant and stayed up til redline



next car will be taking this a step further... adding an aftermarket ecu, front mount, and a full t4 to that setup

BLUE TII

It doesn't boost at idle :P, it boosts off idle- meaning driving at 1,000rpm idle, floor it and it gets positive manifold pressure in a couple tenths of seconds.



I get 14-15 mpg commuting, 17-20 mpg freeway and 8-10 mpg on tanks that include a race weekend.



The people at the Auto-X and hillclimb think the car has monster power and 7,500 rpm is good top end, lol. It probably has 300-400 RWHP.



It is a stock hybrid turbo w/ 60mm external WG.



8.5:1 comp rotors when I can get them, but 9:1 now

Ser 5 rear housing

Ser 5 rotor housings

Ser 4 inter and front housings

RA 2mm seals (I am not recommending these, just using them)



Porting-

-Large 2ndary ports (basically the largest you can fit in the S4 front housing) with large runners and early opening.

-Small early opening primaries, but with larger runners.

-Exhaust ports open a bit earlier, close a bit later. Attention to flow not big timing.



Oil mods-

-Oil pump pick up velocity stacked

-ported, polished oil pump cavities

-relocated oil cooler outlet

-loop line

-e-shaft thermal bypass eliminator

-Race e-shaft rotor oil jets

-Race oil pressure regulator

-relieved e-shaft oil galleys

-windowed, clearanced stat gear bearings

-ported/polished stat gear oil galleys

-largest FD rotor bearings

-RB pan baffle

-7+ quart competition oil pan



Misc mods-

-rotor housing coolant jacket mod

-BR10EIX spark plugs



Here is a thread w/ pics of the original build of this engine-

http://www.rx7club.com/showthread.php?t=489429