2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.

high performance rotary...

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Old 02-24-02 | 07:37 PM
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high performance rotary...

I am wondering a couple things....
In a rotary, how do you lower compression, for High PSI turbos... And how do you raise redline? balance shaft and rotors? I dont know.... but I'm sure some of you must.
Old 02-24-02 | 07:58 PM
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get new rotors if you want lower compression, no other way that I know of.. balancing I have no idea
Old 02-24-02 | 08:26 PM
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how much do new rotors cost? where can I get them? I checked a cuople regular sites and they had nuthin for the RX-7.
Old 02-24-02 | 08:31 PM
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From: https://www2.mazda.com/en/100th/
you need 87-88 t3 rotor they are the lowest compression available, expect to pay around $400+ each new.

mike
Old 02-24-02 | 08:49 PM
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where would I get those? and whats the compression ratio?
Old 02-24-02 | 09:30 PM
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The 86-88 turbo rotors are 8.5:1 CR and are the lowest you can get. What do you have now?
IMO, you're best to stick with what you've got.
CR x boost pressure ratio = effective CR (ECR)
So a higher CR and lower boost will give you the same ECR (and hence roughly the same power), but you'll have that higher CR throughout the rev range as opposed to higher boost but only at higher revs.
Old 02-24-02 | 09:30 PM
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lightened rotors gives a higher redline, there may be other ways, the E-shaft can't take much over 10,000rpm
Old 02-24-02 | 09:32 PM
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rotories already have a lower compression than most piston engines
Old 02-24-02 | 09:43 PM
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86-89 engines have lower compression which is about 8.5. There is a 7.5 on the 13B turbo of 1984 but it is a J-spec engine so most likely you will not find it. But to give you a hint compression is not such a big issue... You can go up to 20 lbs of boost on non-turbo rotors.
Old 02-24-02 | 09:47 PM
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There is no 1984 13B Turbo, these weren't made until 1986.
Old 02-24-02 | 09:52 PM
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e-shaft? is that a special brand, or do you just mean the eccentric shaft?

basically, for my the 7, here are the minimums of what I am looking for:
8500rpm redline, power peaking 7500-8000 rpm
min. 1 bar of boost. 2 bar max.
2000 lbs or less
400 hp
Old 02-24-02 | 09:52 PM
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o, and legality isnt an issue. Its not gonne be driven besides to the race, and maby once or twice during the week to keep everything crispy.

Last edited by sinfestboy; 02-24-02 at 09:55 PM.
Old 02-24-02 | 09:56 PM
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Originally posted by sinfestboy
e-shaft? is that a special brand, or do you just mean the eccentric shaft?

basically, for my the 7, here are the minimums of what I am looking for:
8500rpm redline, power peaking 7500-8000 rpm
min. 1 bar of boost. 2 bar max.
2000 lbs or less
400 hp
2000 lbs or less? you better start saving for a fiberglass body
Old 02-24-02 | 10:14 PM
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Originally posted by Angel Guard Racing Team
86-89 engines have lower compression which is about 8.5. There is a 7.5 on the 13B turbo of 1984 but it is a J-spec engine so most likely you will not find it. But to give you a hint compression is not such a big issue... You can go up to 20 lbs of boost on non-turbo rotors.
i have seen 28psi on non-turbo rotors.
Old 02-24-02 | 10:25 PM
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Originally posted by InfiniIIIREX

2000 lbs or less? you better start saving for a fiberglass body
Its gonna be TOTALLY stripped. not even a passenger seat.

I need to put whats gonna be my rx-7 in my sig, so ppl know what I'm talking about...
Old 02-24-02 | 11:49 PM
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If it's only going to be on the race track, build yourself a tube frame That'll get the weight down.

Oh and one more thing, if you ARE sticking with a regular body, you can ditch twenty or thirty pounds (or more?) by killing the sound deadening material.. Go to a party store and buy some dry ice (or look up "dry ice" at www.yellowpages.com). Yank the carpet out and take that stuff, drop it on the floor panel where the sound deadening is at (helps if it's cold out already) and let it sit there for a little bit, then move it, and take a hammer and *WHACK*.. if you got it cold enough it should come right out in rather large chunks.
Old 02-25-02 | 12:18 AM
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Barwick: Not enough money. the reason I chose FC is because I have heard that for 10k plus the price of the TII you can get 12's in the 1/4 and 1g on the skid. Im looking for 11's and .95g
how much does that much dry ice cost? sounds like a damn good idea... that 30 lbs, and the weight of the carpet... thats a good 45 lbs.... damn!
Old 02-25-02 | 02:59 AM
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if u got some mates in university science department it wont cost u anything
Old 02-25-02 | 01:15 PM
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their was a 12A turbo in japan
Old 02-25-02 | 02:22 PM
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Re: high performance rotary...

Originally posted by sinfestboy
I am wondering a couple things....
In a rotary, how do you lower compression, for High PSI turbos...
Get rotors out of a 1986-1988 Zenki turbo model.&nbsp At 8.6:1(?) CR, it's low enough to handle 30psi, if you're crazy to try it like the PR's!

And how do you raise redline?
Go stand-alone...

balance shaft and rotors? I dont know.... but I'm sure some of you must.
The most famous shop is Racing Beat.



-Ted
Old 02-25-02 | 02:23 PM
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Originally posted by InfiniIIIREX
rotories already have a lower compression than most piston engines
You haven't seen a Starion/Conquest motor at 8.0:1 CR!



-Ted
Old 02-25-02 | 02:28 PM
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Originally posted by sinfestboy
Barwick: Not enough money. the reason I chose FC is because I have heard that for 10k plus the price of the TII you can get 12's in the 1/4 and 1g on the skid. Im looking for 11's and .95g
What the #)$&#$()?

$1,000 3" full turbo back exhaust
$150 fuel pump
$100 intake
$400 boost controller
$500 sticky tires

That's a high 12-second 1/4-mile car that does 1.0g+ on the skidpad.

What the hell is up with you?&nbsp you talk a lot of smack (see other thread on 13B-REW and being able to afford professional fabrication), but you have no CLUE on what these things are capable of?&nbsp You post a lot of question looking like you're trying to build a MONSTER vehicle, but all I hear is questions upon questions upon question...

Care to give us a background on who you are?&nbsp Are you a serious racer who has the money back it up or some 14-year old kid with nothing better else to do?



-Ted
Old 02-25-02 | 02:32 PM
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My money's on the latter...
Old 02-25-02 | 03:11 PM
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Thats cruel Ted, but funny. I'm curious also.
Old 02-25-02 | 03:22 PM
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Maybe it's just me...&nbsp You should see all this person's questions in some of the other forum sections.&nbsp I just went through an involved answer on turbo models in the Single Turbo section.

I was kinda irked that he made a 13B-REW conversion sound so trivial.

I've got a headache...maybe that's why.

For $10k, my FC would've gone 9's!&nbsp Hey, maybe he mistakenly typed "12" instead of "9"?&nbsp Yeah, that's it...that's the ticket!



-Ted



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