you could scallop the rotors themselves as well. and yes, i would get higher compression ones. the rx8 rotors are higher comp and slightly scalloped already, but i beleive you can use the old na rotors and scallop those.

a pic of the rotor https://www.rx7club.com/attachment.p...hmentid=105343



as you can see, the purpose is to keep the port open just a bit longer, allowing more air to rush in. this way you don't have to go to a full on 1/2 bridge or bridge, to get the extra airflow.

 

hmm so i can do an extend port, get some rx8 rotors for higher compression, scallop them a little more, and this will work? anyone done it? what kind of driveability am i looking at?

 

i'd stay away from the rx8 rotors for anything that spins fast. the apex seals can bow as they cross the peripheral exhaust port. if you do use them, try to keep out of the high (6500+) rpm's for extended periods of time.

 

does this have to do with the rotors themselves or just the seals used? this is a very important issue.

ive read more about the scalloped rotors, and it seems that with an extend port and rx8 rotors, i would be gaining more intake on the port and not losing the high compression since the rx8 rotors are already 10:1 WITH the scallops. i think if i DID use rx8 rotors, i would keep them stock and not deepen the scallops. anyone have thoughts on this?

speeking of the renesis... has anyone done a 3 rotor N/A renesis? theres a turbo one on the rx8club putting out 650... wow. theres got to be a drawback somewhere about an N/A 3 rotor renesis.

 

not a true renesis, as mazda doesn't make an intermediate plate with side exhaust ports, like you would need for a 3 rotor. someone may have used the rx8 rotors though.

 

forgot about the side exhaust. is this the only real issue with a 3 rotor renesis? i was talking around the machine shop today about custom making plates and it seemed pretty doable... damn if that were the case, id just go strait for the 3 rotor renesis and start selling kits!

 

this is kinda off topic, but after further investigation of the renesis, i believe a TRUE 3 rotor renesis is possible.

i drew up what the new intermediate plate would look like. the only issue would be making sure that this new intermediate plate was the exact thickness of the 20B intermediate plate, so that the normal 20B eccentric shaft could still be used.

heres a good view of the intake and exhaust ports on a stock 13B renesis:


heres my sketch of what the new one would need to look like:


the next issue would be controlling the new intake to account for a 3rd rotor (9th intake port) and the jet air injection system and all of those goodies. but im sure those are minor set backs once the intermediate plate is made.

is there anythign im missing? (besides my mind and a money tree)

 

The Rx-8 rotors are best for use with full or semi p-port motors, as the extra compression is a benefit. As far as side port intake, little to no gain is brought on by using them. Rx-8 rotors also cannot be scalloped much at all due to the side seals being placed further out on the rotor itself. You'd then have to machine the rotors with deeper slots to use standard FC/FD apex seals. I didnt have problems with cooling, and had a redneck Koyo rad. with no shrouding, one stock fd oil cooler, and one stock FC oil cooler. I took my engine up to 8,500 rpms on a daily baises, and for very extended times at tracks, and it held up great. The intake I did was full custom, as was the header and exhaust as well, expensive and time consuming to make. If you want to make 300 whp its quite easy on street port only, I made over 335rwhp on street port without full tunning. The 310 dyno you saw was when the computer was messing up at high rpm, and later was corrected.

As you may know I am selling a kit for the 20b to drop into a FD without any rack relocation. I have two kits done and ready for sale. Ask me if your interested.

 

^ah yes more good info!!

especially about the rx8 rotors, as i DONT plan on doing a P port. so they are out of the picture.

how much are the kits your selling? im trying to do as much work as i can myself, as i have the resources to do it, but it may just be worth the time and effort to get something thats proven.

 

35k damn bro i think youre trying to put an engine that don't even exist lol a 5 rotor, i think 10k is a good way to go on the 20b but 35k damn man, it has to have gold rotors and housings lol

 

friend of mine made 233hp on a stock 20b na (no porting, stock mani) and a VEMS today with an open header, he used a i believe a t2 cat and made something like 228 or something.

 

$1,570.00 is the total out the door cost of the conversion, which includes the parts you send to me and I modify and send back.

 

$1570.00 does not include the block, correct? What ecu? Your just referring to the 20B block modified, what else? I know there was another thread where you explained this, mind linking to it?

Tim

 

Tim the quote is everything needed to install the engine in it's stock location without relocating the steering rack and avoiding bump steer. From memory:

Alternator bracket
Sub frame mod
Rack & pinion mod
Engine mounts
Ect.

 

T-von has it right. The kit in detail is as follows-

(2) custom steel plate engine mounts
(2) polyurethe motor mount bushings
(6) precision machined spacer so make the engine mounts bolt onto stock studs
(1) machined tensioner
(1) idler pulley
(1) machined water pump outlet
(1) modified power steering bracket (customer supplied)
(1) modifed stock rack (customer supplied, pressure fittings must be changed)
(1) modified subframe (customer supplied) can be done by yourself if you prefer not to ship
$1570 total cost (Mig welded mounts)
$1670 total cost if you prefer Tig welded mounts

 

that includes much more than i thought, definately something to consider for time savings. do you have pics of any of these things?

 

i think most diy's find that anything that saves a significant amount of time is worth its weight in gold.

 

MAN! thats a lot of work and money for 300hp, FDs dont feel that great with 300, but around 450hp things start to get interesting, and i cant imagine 600hp. just my OP.

 

MAN! thats a lot of work and money for 300hp, FDs dont feel that great with 300, but around 450hp things start to get interesting, and i cant imagine 600hp. just my OP.

 

depends really. 600 is just undrivable for most things except drag.

350-400whp makes for a really fun car though.

 

Your forgetting this is just a starting point. You have won half the battle just getting the engine in the car and running. Some people feel you have to go all out with this install the first time. IMHO it gets too involved and expensive that way. Once the engine is in there, then you can furthur mod to your hearts content.

 

Are we comparing apples to apples?
A 300hp 13B is a whole lot different than a 300hp 20B...


-Ted

 

Yep, you'll have a ton more low to mid range torque and a better souding exhaust note.

 

everything depends on what you want...

i woudn't waste time with a 3 rotor for 300 hp, but other guys might. it's unique, it's cool, blah.. to each his own. i like seeing everything done.