We had a little rotary dyno day hear in Kansas so i decided to weight and dyno my 84 RX-7

Did three runs with a best of 120rwhp/ 109lb/ft torque
took it to a scale with a total gross weight of 2160

Mods.....

Stock port 12a
RB Holley carburetor (465 CFM)
RB Intake
RB exhaust

That is basically it, i was guessing around 130hp but im happy with what i got.

 

those are pretty good numbers for a stock port. i was guessing a stock port usually pushed around 100-110hp.

 

im not sure how to get any more power out of this motor with out porting. i was thinking bigger jets or might even try rotary shacks new header and see how much more power i can make with it compared to the racing beat one.

 

either way thats still pretty good for stock...bigger jets will give you more power but an increase in gas use..

 

are you running the stock fuel pump?

 

Stock at the flywheel is 105 hp. This is rwhp of 120. Add back in drivetrain losses at 12% and at the flywheel I guesstimate about 135 hp. I would have thought you would be putting out more as well. What kind of dyno was it?

 

i have a carter fuel pump and we did this on a dyno jet. i will try and get the dyno graph and some video up soon.

 

****, so help me clear up my head, i'm fairly new to the car scene being this is my first car. and i had always thought that rwhp meant what was being pounded onto the pavement after all the loses due to drivetrain? and flywheel HP was just what the engine had. which would always be greater than rwhp...now i'm just plain confused.

 

hp number is ok, there might be a little more hp in it depending on the health of the motor, exhaust, and a little tuning....

i'm wondering why its so light! 2160 is really really light!

 

the car is gutted, just have the dash and the seats. there was an EP RX-7 at the meet that weighted in at 1950! now thats light!

 

 

NICE CAR ^^^

Those numbers aren't too bad. I would have guessed closer to 130RWHP with those mods, but some tuning may be in order if you haven't done so already.

Blackdeath, that is exactly what wheel horsepower and flywheel horsepower are. What T_g_Farrell was saying is that with 120RWHP, after drivetrain loses with a conservative 12% loss, the flywheel horsepower would be about 135. Losses for front wheel drive cars are usually lower since the power has to travel through a shorter drivetrain, and all wheel drive losses are usually higher since the power has to go through 4 different wheels and axles, and more than one differential and a transfer case. Also if you err on the low side of the scale then you won't be too far off your actual horsepower numbers.

 

nice numbers for a 12a. do you have any interior pics? my car is gutted too

 

the only pics i have right now.

 

i don't think the door panels weight that much, i would just leave them on. that is, unless you don't fit in the car without it.

the panels actually help me with turns. when i took mine out i was almost falling out of the seat. I'm 6'3 250 pounds.

 

sweet, well, that's still quite a nice gain over stock.

 

Oh yeah. Stock wheel horsepower is close to 80. So nearly 40 horses with his mods is not too shabby at all.

 

what did the other cars turn out ... especially that ep-7 car

 

The E Production 7 made 185hp with a street port 13b. hear is the video of his run, it was ******* loud!!

http://www.youtube.com/watch?v=6cR1Mp5rqrc

dont remember what everyone else made but i do remember the highest hp was by a 87 TII with 242hp/233ft lb torq and the lowest was by a first gen that made 77hp/ 89 ft lb torq

 

There is a lot of power to be found in the ignition system. I wish the "transistor trick" module was still available, because that really made a difference.



.

 

if everyone dynoed kinda low, than it might just have been that dyno that day....

 

its possible. im going to go back after the carb is tuned, bigger jets and maybe the new rotary shack header.

 

I was hoping to make that dyno day, still haven't finished the wb or gotten it retagged yet. Good numbers on your's. As to your PM, check the YellowPages. There has to be a wheel shop somewhere in KC.

 

that would put the drivetrain loss at almost 24%, making a guestimate of 12% an extremely aggressive estimate, not a conservative one. a conservative guess would have been in the 17-20% loss range, and would put bhp most likely some place north of 140bhp.

1-(80/105) = 23.81%

that said, those are some pretty impressive numbers, especially for some fairly minor upgrades.