RX7WEEE

iTrader: (16)

small single like aT66 would be just the ticket, it'd work perfect for what you want. smooot power band.

me i dont care if boost didn't hit untill 6k... cough what i was doing with my old FD cough... GT45 cough

oh yeah with big single 20b's its not 200hp gain within 500 rpm its about 400.....

GUITARJUNKIE28

^lol
my avatar was in my commuter car, so my def. of streetable is pretty close to yours. can you drive it under any condition without it blowing up? ok, it's streetable

so if we stick with the twins on the streetport, do you think we ought to run them in parallel instead of sequential? 10 psi @ 1700rpm just sounds cool though.

RX7WEEE

iTrader: (16)

so does 900rwhp at 8k... and 120rwhp at 5k and below sound good? .... :P

for my swap im going to have to run stock twins untill i get money for the biggest single i can spool...

GUITARJUNKIE28

do a peripheral hybrid but not on the stock twins!!! i'd rather just run it n/a until you get the big turbo.

my old sp with the hybrid was fun as hell to drive! 200whp @ 3800 rpm, and 301 @7100. usable power everywhere, just not enough of it. my bridge had something like 160-170@ 3800, and 386 @ 7800, but the hp was relatively flat from about 75 to 82.

RX7WEEE

iTrader: (16)

nice!.... not on a 20b right?

GUITARJUNKIE28

naw, sp was an s4 13b and the bridge was an s4/5/6 frankenstein combo. basically a spare parts motor, but worked very well.

my problem with the hybrid is the stock hotside just couldn't flow as much as the compressor coud produce. a clipped turbind would definately have been in order there.

ReZ311

iTrader: (4)

Only problem is, rotaries don't have a bunch of torque. Do you have proof of this? Perhaps pictures of a damaged crank?

I'll be running sequential on the 3 rotor with a streetport.

RX7WEEE

iTrader: (16)

[quote]The first 2000 motors (first run) are the ones that Mazda had the problems with, and had changed lots out on warranty to the newer motors. Main problems were with the intermediate housings, not the eshaft as many people believe.

Most of these engines were the first to turn up in AUS and NZ as they were all removed from Cosmos in Japan, returned to Mazda & then sold off to various wrecking yards in Japan. Supposedly the dealerships weren't allowed to dismantle these engines. They were to be returned to Mazda complete & in return Mazda would send a brand new upgraded one back to the dealer.

Stock first run motors have a short life and its not a matter if they will fail, rather when, especially under higher boost levels (anything over 12psi).

The strengthened housings of the 2nd run (B to C) make the motor much more reliable and hold higher boost. These are the desirable engines.

As for the strength of the eshaft I have only heard of a couple people having problems in that area. I have never seen even a picture of a 20b eshaft failure.
Any problems mentioned with the eshaft however are on fist run engines.
If the center rotor fails it is more to do with the weak intermediate housings than eshaft flex.

I have heard and seen a pic of a 13b eshaft which had failed just in front of the flywheel, and since the 20b shaft is no thicker in that area I would imagine that would be where to expect it to fail as well.
There is a extra bearing in the 20b to support the eshaft so it's no worse than a 13b for bearing area.
Reving a rotary to high rpms stresses the eshaft more than high hp at low rpms.

The 20b eshaft is lots strong enough if the rpm is kept below 7000rpm which seems to be where the power drops off anyhow.

The eshaft has been wrongfully blamed for causing engine failure, when in reality it was the fault of the weak intermediate housings.

Early motors 001 all the way to the late C motors have the dowel pins that have the step, and in the later ones the stopped using the step dowels and went back to using all the same pins. Cant imagine what the idea was to use a pin with a step on it - there doesn't seem to be a benefit at all.

I have also seen a few engines arrive here in Australia with the numbers ground off. This seems to have happened in North America as well. If they were ground off in Japan, they will still have the number stamped on the front plate under the alternator(cant get the grinder in there to get that one!).
Most of these engine's have been rebuilt for test purposes by the factory by using bits & pieces from various engines, hence the grinding off of the conflicting numbers.[quote/]

94RHDFD

iTrader: (3)

[QUOTE=RX7WEEE]the stock twins on the cosmo are soo small that in paralle they spool almost too fast... in seq mod they had a problem with the 2nd turbo hit and it would create too much TQ at too low of a RPM and would damage the E shaft, this was on some earlyer 20b's

Actually, this is partly true, early 20b's had a problem with "snap torque" on stock turbo's because @ lower rpm while boost was being made the E-shaft would want to move side to side damaging the shaft, on early motors with a single turbo, you may never see this problem

RX7WEEE

iTrader: (16)

[QUOTE=20B 3rd Gen]ya thats why i also quoted what my previous post said so im right and wrong in a sense. :P

GUITARJUNKIE28

anyone have an idea of how much hp the stockers are capable of?

and when do i get my plane ride?

RX7WEEE

iTrader: (16)

pettit said they have made 500hp with a little mods to the stockers.

plane ride is in a few months

FDNewbie

iTrader: (10)

Word from the other thread (I believe David Hayes' thread) is that Pettit blueprints and upgrades the stock twins, and makes 550 HP @ 7500 RPM and 460 Lb-Ft @ 5500 RPM.

GT1-20b

My good friends,
550 Hp @ 7500 Rpm equates to == 385 Lbs/Ft. of tourque ( AT 7500 RPM ! )
Use World Standard SAE formula : Hp.= (Tourque X Rpm.) / 5250.
When You plug in the #'s , 385 Pounds Feet of tourque is what You get... Period.
You can argue about Correction factors, & Atmospheric preasure , and all of that! BUT,
That IS what is IS.
Pettit' "IS" at See level.
Those #'s ARE (Realistic).
What is NOT REALISTIC is the 460 Lbs. @ 5500.
LETS GET REAL.
At that Rpm, the engine is NOT anywhere near the "Sweet" spot. of the Intake manifold'S "TUNED LENTH"
It's tuned by Mazda @ 6200 Rpm.
There are many other variables in this equation, but for now, this is as "advertized".
At 5500 Rpm, The engine is "No were close to Peek", but rather on it's way UP, climing the power band.
You guy's !!!, need to DO a little mathematics to see were the REAL #'s are at !
Best to ALL !

GT1-20b

ReZ311

iTrader: (4)

Who gives a **** if it's Dyno proven.

GUITARJUNKIE28

thanks for the info, but what was that rant about? i just asked what the stock turbos were capable of so i have a ballpark of what to expect before we go big turbo.

FDNewbie

iTrader: (10)

I personally found the info to be insightful, esp. since I took it as written, for granted. On David Hayes' thread, a lot of ppl said the 550hp couldn't be achieved w/ sequential twins...

ReZ311

iTrader: (4)

For street driving, sequentials is the way to go.

Evil Aviator

I think you need to review your math before you attempt to insult Pettit again.

GUITARJUNKIE28

i like to eat pizza sometimes.

ReZ311

iTrader: (4)

With Mushrooms ???????? LOL

FDNewbie

iTrader: (10)

OMG that was so freakin retarded, it HURT. What the... I'm at a loss for words...

GUITARJUNKIE28

viewed best under heavy inebriation

GT1-20b

Regarding Your post, the following are the FACTS:
A) The Hp. Formula IS CORRECT, therefore the "math" IS ALSO CORRECT.
B) He is a friend, with mutual respect regarding each other's work.
C) No "Insult" at any one intended. Just a mathematical obsevation.

In respect to the FACTS, I will eleborate further:
- Pertaining to the "Math" part : Substitute the variables with the values given, and work out the equation. If You end up with anything other than what I posted,
then a Re-Fresher course in 10th grade Algebra might be in order.
- Pertaining to the "Insult" part: The only Insult here, seames to be one of a "Persona Nature" intended towards me.

Wth all due respect,

GT1-20b

GUITARJUNKIE28

weee,
wanna do a peripheral hybrid? it'll be fun--i promise