TopGunM2k

Anyone know what the redline for a 13b 4 port that came on the rx3's and rx4's?
I just recently did a street ported 13b 4 port swap into my rx7 and am using the rx7 tach to shift. I have ran it to the 7-7 1/2 redline a couple of times, just want to make sure that I'm not doing any serious damage by doing this.

Midwest 7's

iTrader: (4)

your not.

DriveFast7

iTrader: (1)

The early 13b 4port was in rx4 and repu only, not 3 fyi. It has the heavy rotors for more torque (not much more). My redline buzzer in repu goes off @ 6500 and the tach is colored yellow at 6500, and a muddy brown @ 7000rpms. So I'd guess 7000 mudline - I mean redline.

My mildly streetported version makes peak hp @6500 so there's no real reason to rev to redline anyways. I set my msd6al rev limiter to 7k.

Hope this helps.

aussiesmg

iTrader: (1)

RX5 also had 13B 4 port.

My BP ran easily to 9000 with stock apex seals, does you engine have improved oil pump, what seals?

TopGunM2k

It's was pulled from a drag 1st gen Rx7, I had it rebuilt by Rotorsport in Santa Clara. From what the mechanic told me, the motor had hardened stationary gears, a lightweight flywheel, the intake and exhaust ports had a mild street port, the rotors where in great shape. All he did was resurface the intake plates, replace the apex seals, o rings and all the other stuff needed for an overhaul. He gave me a quick estimate and told me that the motor's red line is probably at 7,500k. Much like you guys - he said that the weight of the rotors determine the higher red line the motor can produce. (had I known - I would have coughed up the extra dough and bought some rotors from an S5 2nd gen rx7.

aussiesmg

iTrader: (1)

IMHO I wouldn't hesitate to run that combo to 8500 rpm.

Siraniko

iTrader: (13)

thats it???? oh come one, you go higher than that. as long as its only for a few seconds, that engine can handle it.

DriveFast7

iTrader: (1)

i wouldn't take it over 7k without balanced rotating assembly and oil system upgrades.

Midwest 7's

iTrader: (4)

not even ocassionaly?

aussiesmg

iTrader: (1)

I did have a RX4 oil pump but my engine builder gave me 8500 and I often ran to 9000 in corners due to gearing, raced the car for 5 years without an engine problem. This was on fast Aussie tracks like Calder Park, Philip Island, Sandown, Oran Park, and more.

steve84GS TII

I treated my stock block 14B 4 port just like my stock block 12A.
With the Yaw Nikki they both liked to rev,Id take em to 7000 on a regular basis and hit 7500 sometimes when Id not shift quick enough.While its common to hear that 8500 is the max for "stock" engines,I just cant see much reason to go up there.Just no power and youll be damn near back at redline when you hit the next gear,which means more drawn out,sustained high RPMs.Both my motors made great power in the 4500-6500 range,so a shift at 7000 put me right back in that meat.

If youve got some porting to take advantage of,then an 8000 shiftpoint might be more inline.But if your gonna teardown to do the porting,take the time and spend the money to make your engine rock solid at those speeds.

Siraniko

iTrader: (13)

nah, you guys are too conservative. We've been rev'ng the hell out of stock 12-A engines for years with aftermarket carbs. how do you expect to win on street racing if you dont do it.

trochoid

iTrader: (6)

Street racing, what's that?. Oh, now I remember, when I had my Road Runner I smoked almost every car that challenged me up and down 'O' street back home. Now with the widebody that has bigger tires than the beep beep did, I can out run almost anyone, if it's not in a straight line. Once I get the straight line performance equal to the handling, I'll be in rotary heaven.

Siraniko

iTrader: (13)

my rule to make an ever lasting engine and tranny.
Rev the hell out of it once a day to clean the internals.
for the tranny when down & up shifting, its a MUST to match the RPM properly. if not, it wont last.

84stock

iTrader: (5)

Get her tuned on a dyno and "see" where your power "is". If you are falling off lets say at 8000 then why go there, if you find out where your torque and power are then you can drive to the ability of the engine. And taking it to 7 daily is a good idea to prevent any carbon build up for sure. My s/c provides a lot of torque but power starts to fall off over 7 so I take it to 7 and shift and fall right into my peak torque curve for great acceleration without compromise.

TopGunM2k

Yeah, I guess the anwser to my question will come when I dyno the car. I still need to get it tuned though - I'm waiting for my venturis for my weber 48 ida to come in and after that I also need to install a bung on the header so I could hook up a y band and tune the carb correctly.