S5 has the grooves in them...just like the 13B-REW ones.
The S4 ones don't.


-Ted

 

Oh gosh, information overload. When you guys finish your discussion, I need a final copy for a plan of action, lol. Really glad to get all this in-depth info however. Thanks everyone!

 

I looked on the GReddy site and it said that purple colored injectors were 550cc. The previous owner of the RX-7 parts car I got said it came with 720cc injectors but I thought I recalled the injectors in the car being purple. So maybe they are 720cc, because there's obviously no point in replacing stock injectors with aftermarket injectors of the same size.

 

OK, I was wrong, they were 720cc/min injectors. I might be getting larger ones if necessary... So uh..... can I get a concise report on what I should do? I think I'm going to focus on building a strong foundation so I cal reliably run relatively high boost levels.

 

Start with a 13B-RE, that would give you the strongest foundation, and would fit relatively easy.

Then, get a good fuel system, haltech, walbro 255, maybe a bosch 044. Good FPR, good injectors, new fuel lines etc.

Cooling system, New caps, new oem or i think there might've been a mazdaspeed thermostat you could use besides oem. Koyo or fluidyne or awr racing radiator. Also get some good ducting, for cost reasons, i'd go with a FMIC, along with good ducting.

Get a good engine builder, make sure you use very good condition housings.

Cover base on all of the other misc odds and ends, suspension, brakes(i'd go with some DOT approved braided lines, rebuilt calipers, good fluid and hawk or ebc pads, for suspension for the powerful motor you want to build, coil overs, tein flex, jic flt-a2, cuso zero 2, zeals)

Then pay for oil mods, and porting in your engine build, and get a nie sized turbo, if you want to make alot of power, which i assume you do, I THINK a GT4088 should get you in the 500WHP area.

THEN, after factoring in all of those costs, add on extra engine modifications, balancing, ceramics, etc etc.

I don't know if i said it before, but for 400whp though, go with a 60-1, 've been told 720s/1600s are good for 400hp.

 

anyone consider apex seal choices for this build yet? oem, aftermarket standard replacement (atkins, ra) or possibly ceramics? what kind of revs are being considered? was an upgraded gearbox (such as the os giken close ratio gear set) considered? i am curious as to how serious mazterdizazter is participating in racing and still being able to street it. cooling system obviously needs to be considered, possibly water jacket modifications from racing beat? imo i would run at least brand new rotor housings and all new seals and springs (upgraded where possible i.e. 3rd gen corner springs, viton oil rings, oem apex springs of course.)

 

Apex seals have not yet been considered. I was originally considering having the entire assembly balanced and getting lightweight rotors so that the engine could rev to 9000+rpms but I may be backing off that idea very quickly. The stock gears will be retained unless I can find a relatively low-cost upgrade. As far as it being a race car that sees mild street use, It will retain all lights, horn, seatbelts and everything required of it to pass safety inspection, and hopefully the drivetrain will be relatively useable on the street when all is said and done. Like I said, very limited street use. As far as the cooling system is concerned I planned on getting a new water pump, a Koyo radiator w/ silicone hoses, new oil pump, stock oil cooler with braided hoses and A/N fittings, and a GReddy FMIC. If I have the budget I will look into water jacket mods. I'm highly considering using new housings; in fact I may have to if I pull my engine apart and one of the housings is scored.

 

Reliabilty?

Stock port/mild street port
New housings
OEM seals
And change the Greddy TD-06 turbo from BIG maybe, to HUGE have-to.

Just boost it. No need for elaborate porting when you're going to cram air down its throat anyway. Just boost the snot out of the thing.

Leave most of the internals stock, I think as far as oil mods and internal parts swapping goes that people often get far too out of hand. Get an RB street oil pressure reg., solid corner seals and call it a day.

Example of the above, people have mentioned hardened stat gears, lighter/different e-shafts etc. If we're talking about strictly reliability how many engines have been torn down to replace the original stat gears because they weren't "reliable" enough?

 

I was kinda wondering/thinking the same thing. If you just ran higher boost with a bigger turbo, had the supporting fuel mods, and had a standalone or something nice like rtek 2 to tune it (wait do rtek 2's change timing?) what would most likely be the first thing to go? What is the weakest link in our motors? If tuned properly would just the pure amount of power it is making cause the apex seals to break? Or is it just pre-det that causes that?

Just to be sure, I do not know and I am asking this to know. Not trying to be a smart ***.

Thanks
~Tweak

 

from personal opinion only:

don't bother with stud kits or dowels.. the engines twist because of detonation, if something is going to give it may as well be a cheaper and easier to replace iron than a set of rotor/rotor housing/apex seals. if you overboost what your fuel can protect to you may have saved your rear iron but you cost yourself half your motor

2mm seals over 3mm, 3mm causes more friction and more wear and like dowel pinning it is overkill and just a cover for faulty tuning or other issues

more oil pressure is not always your best bet, in any turbo application you must always divide the oil pressure to the turbo or it will fail prematurely. the most oil pressure the turbo should be seeing is 35-40PSI, so having 120PSI of line pressure means you will have to restrict it that much more at the turbo or step up and install a regulator to feed the turbo since the higher the oil pressure is the more difficult it will be to keep it stable from low RPMs to high RPMs at the turbo itself

 

Well I've seen some prety high HP stuff, and on here a member ErnieT is making over 700whp and that's not enough power to simply break an apex seal....when tuned properly.

Thats usually the downfall of most high HP, tuning.

But since the OP will be using a Haltech (at least, he damn well better ) , getting a good conservative tune will be plenty for achieving NICE power, and having a car that runs trouble free for a long time.

Honestly the biggest part is mostly just the little things like fuel injectors, new vac lines etc. Thats the stuff that'll leave you with a blown engine (old injectors) or on the side of the road (blown heater core hose for example)

 

So what do you have to say about getting the rotating assembly balanced? Worth it to have the extra volumetric efficiency? If I can rev the engine higher would it even be beneficial or would power levels drop before reaching that higher rpm limit? Oh, and just kick me if this all sounds stupid.

 

Well, a full dynamic balance wouldn't hurt thats for sure. However as far as balancing and clearancing ONLY for the purpose of higher RPM's (higher meaning 10K+) is a bit of a waste on a car with a stock intake manifold since power will drop off before then as you mention.

I'd say a balance would be worthwhile though since its also not a tremendously huge expense or inconvience.

 

Revving higher on a small port will only strain the engine without gaining significant power.


-Ted

 

plus most turbos just won't produce power that high up.

 

That's what I figured. What about using an FD intake manifold? I've yet to research the advantages of switching to one.

 

Its not really all that interesting.
The front stationary gear journal on the e-shaft has two oil feed holes drilled into it. The rear stationary gear journal only has one. Cross drilling simply means sticking your drill into that single hole and drilling right through, followed, of course, by a chamfer on the new hole and a good clean-up to remove metal filings.
In addition to cross drilling, a loop line should be installed. The front stationary gear always sees lower bearing pressure than the rear, due to several pressure bleed-offs (MOP and turbo), as well as 3 extra 90 degrees turns that the rear bearing does not see. This is the reason why the stock e-shaft is only cross drilled at the front. By adding a loop line to the front iron from the rear oil filter to create a parallel path for the oil to flow to the front bearing, you can pretty much equalize the pressure between the front and rear bearings.
Common modifcation on high-rpm NA engines. Rarely required for street driven turbo engines due to the much lower redline.
BlueTII has a thread on it here:
https://www.rx7club.com/showthread.p...ight=loop+line

Bolt stretch between New s4 and s5 tension bolts isn't any different, so I don't think the S5 bolts are weaker. I think the S5 bolts have a tendency to break more simply due to the fact that the S5 rotating assemblies get revved higher and induce higher harmonic resonance unto the bolts, hence the reason for the ribbing.

 

Bolting the S6 UIM onto an S5 lower:
- Shorter UIM runners for a slight shift upwards in the powerband.
- Allows fitment of the S6 TB, which uses larger secondary butterflies for less flow restriction
- Deletion of the plenum on stock TII UIM for reduced throttle transition smoothness
- Deletion of the equal length runners attained when using TII UIM with TII LIM. Causes an imbalance in airflow between the front and rear rotors.

Not worth it if you ask me. For the cost vs. gains vs. losses, I would much rather have an extrude honed S5 UIM/LIM combo.

 

I just put a lot of money into building my "ultimate" 13BT. Well, ultimate for my goals/needs.

I have lightened/clearanced s4 n/a rotors (9.4:1), rx-8 e-shaft, racing beat stat gears, 11lb flywheel, FD oil pressure regulator. Ported to pass emissions (minimal overlap) and a nice sized exh port. w/ lots of coatings
I'm going to be running a hybrid and upgraded stock mount.

My goal is for something that will pass by cali visual/emissions and be very responsive. I want 300+rwhp and reliability, so I built up the motor to make power instead of a bigger turbo or more boost so I could run a stock mount intercooler and hybrid....

I would do things differently then, but I change my mind on everything each and every week.


Just get a good standalone, I'm going w/ a Wolf v500. OEM rebuild kit and OEM 2mm apex seals, new housings, s5 irons and rotors and have the motor balanced.

With a properly set up turbo, lightweight flywheel, good intercooling and good ECU/good tuning you can easily make that horsepower and great response.

A lot of people like the haltechs, I dunno, but have too many friends w/ bad experiences, same w/ Microtech. Not saying the Wolf is flawless, but I definately like the features.

I went overboard, because I'm a kook. I wish I went milder for the turbo motor, or went N/A w/ a very built motor. My motor is a bit overbuilt for the turbo I'm running and I have to slightly rig my setup.


However, my engine builder is awesome regardless of my indecisive self and is doing a great job
www.azrotaryrockets.com Glen is the man

 

This is all very useful. Keep the suggestions coming guys. Thanks!

 

Here is the path that I am going.
https://www.rx7club.com/2nd-generation-specific-1986-1992-17/new-style-636258/

 

Like I said, just balance the internals and spend the money elsewhere, boost works wonders.
You don't need all of the high RPM lightened goodies, a flywheel is a huge amount of mass. And the stock motors are already good for 8500rpm. And thats w/ very very sloppy balance tolerances.

But then again, this is me being crazy and paranoid. I haven't even driven my car yet, haha.

 

Well I just jumped in to make a post. My opinion, if you have the money, get the engine balanced and setup up with eccentric and stationary gears made to handle 12000rpm, and get the dowel modifications, then if you just run basically stock rpm range or even up to 9000rpm with a bigger turbo and mild port, you won't be stressing the internals anywhere near what they can handle, then you won't have to worry about the engine going out if you are just doing autocross or track events. I may be full of it, but seems like a nice thought. I'd like to do it, but of course if it can handle high rpm...well you know where the road leads...