Stock engine performance and RWHP?

[13BRV3]

Greetings,

I'm in the planning stages for an 818C, and I'm also a rotary engine fan, so I've been thinking of using a RX-8 Renesis 6 port engine. The official HP numbers changed, and were still not completely believable, but I think 190 HP at the wheels is a realistic number for the stock engine, which is NA. I'd really like to stay NA at least initially, just for the simplicity of it, but if it wasn't enough power, turbo is certainly possible.

I've been trying to get an idea of how that compares with a stock, and relatively healthy donor engine from a WRX. I did some searching, but the only dyno numbers I find seem to be modified engines. I guess the question is- what dyno rwhp numbers do people get with the stock engines, and how satisfied are you with the performance of the car at that power level?

Thanks,
Rusty

[Hindsight]

Stock EJ WRX engine is about 165-175 to the wheels. I believe that's good for a 12.X 1/4 mile run. But with just an ECU tune on the WRX (~$250-500), you can get 250-270WHP.

[13BRV3]

Stock EJ WRX engine is about 165-175 to the wheels. I believe that's good for a 12.X 1/4 mile run. But with just an ECU tune on the WRX (~$250-500), you can get 250-270WHP.

Is that 165-175 rwhp in the WRX, or in an 818? I'd expect the AWD in the WRX to have more loss than an average 2WD setup. To get that much with a tune, it has to be increasing the boost a significant amount?

Rusty

[Bob_n_Cincy]

I am running stock tune in a 2.5L 2004 FXT AVCS engine. Crank Rated at 210 hp at 5600 RPM and 235 ft-lb torque at 3600 RPM.

Her is my 818 dyno chart at the wheels. CAT only, no muffler. AWIC, TGV delete.

[13BRV3]

Thanks. That's good info. HP isn't so much of a problem for the rotary as torque, and I'd expect only about 150 ft-lbs based on what I've found for the RX-8. I fear that would be a bit weak for the 818C. A turbo would fix that of course.

Rusty

[Bob_n_Cincy]

Thanks. That's good info. HP isn't so much of a problem for the rotary as torque, and I'd expect only about 150 ft-lbs based on what I've found for the RX-8. I fear that would be a bit weak for the 818C. A turbo would fix that of course.

Rusty

Rusty,
I am very satisfied with the performance with stock tune.
Watch this short video:
https://www.youtube.com/watch?v=xVEqS3Gs9SM

https://www.youtube.com/watch?v=M0Piy6TB5Wg

[13BRV3]

Hi Bob,

Thanks for the links and comments. I'm not quite sure what I'll do at this point, but there's a pretty good chance I'll end up building an 818C. I'm a builder/tinkerer, and I just sold my 2017 Corvette because I couldn't justify modifying it, or taking it to the track. I'm looking for something that would be an ongoing project, and that I could financially justify putting on a track occasionally. The path of least resistance is clearly to build it with the stock Subaru, but I love rotary engines, and it would make a great project. For now, I'll continue gathering info.

Cheers,
Rusty

[Canadian818]

A NA rotary would be so light! I’d imagine it’d still be quite quick too. Would you be trying to use the factory rx8 wiring? Not sure if the CanBus would make trimming the harnesses more difficult. Adaptronic now makes a great plug n play ecu for the rx8, and could probably help with eliminating some unwanted systems.

[13BRV3]

Hi Adam,

I honestly haven't thought through all the details yet. I figured there was probably an aftermarket ECU, or at least I hoped so :-) I'll definitely look into the Adaptronic unit.

Thanks,
Rusty

[Mitch Wright]

I have driven Bob and Michaels car and I am impressed with the performance with the really mild tune.

[13BRV3]

Thanks, that's good to hear. If I do this, it will almost certainly be with a rotary engine. I'm all about handling, and much less about acceleration, so I'd bet I can get enough power out of a Renesis engine to be satisfied. I was trying to figure out if there is an option for a little lower gearing if needed, like maybe the allowable models of the STI transmission? Revs are no problem. Zoom, zoom :-)

Cheers,
Rusty