Got the car on the scales today. Total 2581 lbs, and thats with full tank of fuel :) Will shed a bit more once I install the CF/Lexan hatch.

https://www.rx7club.com/attachment.p...hmentid=547251

I see corner-weighting in your future! Very light!

Yep, coilovers have never really been adjusted, so as you can see at least in the rear weights are a bit off.

Well today was the big day. Logan braved the weather and made the trek out to the dyno to get the car tuned. I'm glad to say everything went fairly smooth and he reported the car ran flawlessly. I literally just got off from talking with him for the past hour or so about how it all went, his impressions and where, if anything to go from here. The runs were video recorded, but most likely wont have those to share until tomorrow. But anyway, onto the results. 345rwhp/262rwtq :)
So, while happy with the results, the car is down a bit from the 360whp we were shooting for. What the thought is, is because of the engine placement the intake runners had to be slightly longer and more curvy than planned. Longer runners causes the torque band to shift left. Logan tells me this is the highest tq of any N/A 20B he has built, and even in driving it he did say the midrange felt very strong. So, I do have the option of re-doing the intake manifold and gunning for that extra ~15-20HP up top, or just leaving it as is. Right now Im most likely just going to leave it as is, and enjoy. I was never out to chase numbers, and even as the car sits it is a 400HP/2600lb car which is nothing to sneeze at. IMO, of course :p:

I know Logan had a long day, hopefully he will chime in with his thoughts tomorrow.

^^Congrats Lenny. Nice outcome! Can't wait to see the vids tomorrow.

Awesome. Can't wait to see more!

Leave it. It's just a number. Now go Drive it!

:icon_tup: :nod: Solid numbers and that is great to hear about the torque curve. Glad it is running and you will be enjoying it soon.

Official dyno chart!

Attachment 635101

So as Lenny has already stated its a midrange torque monster for a 3 rotor all motor. Sometimes its easy to forget that a 20b n/a is just like a 2 rotor on 7psi but you can never turn up the boost.

Definitely a great point and shoot powerband. The engine is still far from fully broken in, the weather prevented getting 1k miles on it. They usually pick up 10+ once past the 1,000 mile mark. The 8.8 rear end turns tight too and we are going to take that apart and see what the issue is. Its definitely eating some power.

All things considered I am very happy, I think Lenny will be too. It can always be tweaked if the time ever comes to reach the 360+ rwhp mark. Tweaking is the name of the game on all motor setups. The torque is the highest I've seen and that means the engine is packing excellent efficiency.

Driving the car was a blast before the dyno. I couldn't run it hard on the way back due to slippery conditions but I'm excited to feel it when the temps warm up!

Video will be posted tomorrow!

Man that torque curve does look really nice. Congrats!

Lenny, I say leave it and enjoy it for a while, you have plenty of time for finding more ponies later. ;)

Very nice Lenny. I bet the car will be a blast to drive. I think it will make an awesome track day car, as the weight to power ratio is about ideal if you ask me. A few HPDE events ago I drove my friend's track prepped 2 rotor FD making around the same amount of HP and it was a blast. Plenty of power and a lot of fun. I'd also guess the car had less torque exiting the turns because of the single turbo and I know it weighed more.

I am sure you posted this, but what did you do to lower the weight on the car? And this may be a Logan question, but I'd like to know about taking the car up to 10,000 RPMs. Based on the dyno chart, the max HP is somewhere around 7,000 RPMs. So, why would you take the car any higher than that? Won't the power drop or am I missing something (like usual) here? I always thought guys took their cars up into the high RPM ranges to make more power.

Thanks for the comments David. I'm sure the car will be a blast. I will use the remainder of the time this winter to get all the other little bits and pieces up to snuff, then plan on driving the wheels off it come spring :)
As for weight reduction, I really haven't done anything yet. Beside the obvious no a/c or power steering , any weight loss can just be attributed to the bare bones 20b. When it comes back home I still have the cf hatch/lexan rear glass, as well as cf hood to swap to. Car will most likely be sub 2500 at that point.
As to the high rpm power, torque does peak right around 6700 or so, and hp slightly higher. Even though tq starts to drop a bit, it is still making ~325whp up to the 8500rpm, and most likely out until 9k also. So it it still making good power up top. The engines that spin much higher are usually pports/semi pports, or something of the like that can flow more air. My side port only engine just can't flow much past this rpm, and tq starts to drop. Perhaps Logan will elaborate a bit more when he posts the vids (I haven't seen them yet either, anxiously waiting), but that's pretty much the jist of it. I wanted this from the start, more of a meaty tq band in the midrange more than an all out top end monster. A semi pport would have probably given me the best of both worlds, but imo a 8500-9k engine would prove more reliable and last longer than a 10k plus engine.

Dyno vid and just a little cruise around

http://s254.photobucket.com/user/fd2...2020b.mp4.html

damn that video is cool. sounds totally pissed.

This build turned out great and should be an amazing car. I wouldn't sweat the number I think that thing will be a rip on the street and a great track car should you take it there.

The weight really caught my eye. Do you typically lose a good amount of weight going to N/A 20b? I always thought the extra motor weight offset the loss of the turbos and components. 2581 with a full tank of fuel is CRAZY light to me. I have a car without a/c, p/s, light wheels, full exhaust, aftermarket steering wheel, and aluminum seats and it's still 2820 with 3/4 of a tank of gas (I do have a custom roll bar in it). I couldn't fathom losing another 200+ lbs.

Thanks! As for weight, I really cant comment on the "norm" for N/A 3 rotor swaps, as most I know go turbo for the big power. Keep in mind my full tank is only 13Gallon, so slightly less than your 3/4 tank. Are you sure your weight is accurate? Stock base/r package FD is around 2750. Just shedding the factory exhaust ,and A/C and PS should be good for almost 100lbs.

my 93 base model (no sunroof) with 1/8th tank of gas weighed 2660. only mods were intake and full exhaust (all AC stuff, seats, etc. were all stock) just for reference.

I've always been interested in how much if any gas was in the cars for the "stock" weights.

I'm pretty sure the weights are accurate as I corner-weighted the car myself last year. They were borrowed scales but they didn't indicate being off in any of the tests I did (like weighing objects and myself) before starting. My car is a touring with a sunroof and stock interior with the exception of an aftermarket wheel, aluminum seats, and my rollbar which adds back 60-70lbs. About the only weight I have left to lose is a light weight battery as far as fairly easy options.

It's just interesting to see that much of a difference so I was wondering how much could be attributed to the engine swap alone.

Yea, in hindsight it would have been nice to corner weigh the car before the swap to see the exact difference.. oh well :/

^ You and me both!

So just a small update on my differential issue Logan had mentioned in his post. I asked him to tear it apart while the car was still there and just check it out for me, and it appears the pinion depth was set too deep originally causing some binding issues. I have ordered a replacement ring and pinion and that is getting redone now as well. I've set up a few differentials myself but decided to take this one to a local "expert" to have done originally just for piece of mind. That worked out well..

https://www.rx7club.com/attachment.p...hmentid=548130

wow, so maybe a little more whp/wtq when the diff is set correctly!

sucks, but good to get any issues corrected :)

Probably. Logan even commented before the issue was found that the car felt more difficult to even push around the shop than normal. So I'm sure it was dragging it down at least a bit. And there's a chance the car may hit the dyno again soon to try out some small tweaks, we'll see how everything lines up though.

+1 on the HP. That diff looks pretty gnarly :(

Was the diff "expert" in Columbus or PA?