Update: Took the car out for a spin last night with the 1000 cc/min nozzle in the Greddy elbow and the 500 cc/min nozzle at the pre-turbo location. Did one pull and blew the charge pipe off the throttle body at about 6,500 RPMs and 22 psi. It look like a mist bomb went off under my hood, which I assume is the good amount of methanol and water in the charge pipe. Based on my setting on the AEM controller, I should have been around 1000 cc/min of injection. IATs still went from about 104F to 125 F and likely would have been around 135 F if I completed the pull. I guess I will continue to dial up the meth/water and see what happens. I used some hairspray on the coupler to get it nice and tacky so it wont slip off again.

Update

Well I dialed the water/methanol up to about 80% on the controller with 1,500 cc/min (~1,200 cc/min). No sign of misfiring or not being able to handle the excess water. No signs of sensors going haywire since coils grounded to battery.

Quick pull from 40-90 mph in 3rd gear.
No knock to worry about
AFR mid to high 11s with a lean spike around 7k, gonna add some fuel.
20-22 psi, 10 psi by 4,000, 20 psi by 4,900
Leading timing 13-16, 10 split
IAT still went from 105-132F (+27 F) during the ~7 seconds of turbo screaming. I guess I can try 90% duty cycle on the pump???
Acceleration right at about 10 MPH/S
At 7,200 RPMs, 21 psi, 35% ethanol content, and 11.5:1 A/F, and somewhere around 600 cc/min of methanol, I am 100% through the 1st stage (1000 cc/min), 100% through the 2nd stage (1,650 cc/min), and 20% through the 3rd stage (1000 cc/min) or around 5,700 cc/min total with an additional 1,600 cc/min of injector left.....
More testing/tuning to come

https://cimg4.ibsrv.net/gimg/www.rx8...79c2e70716.jpg

:icon_tup: :icon_tup: :icon_tup:

Congrats, Stroker, on working thru the issues. :icon_tup: Curious... was the ~10mph/s acceleration “peak acceleration”?

Hey SC , how are you getting your 10mph/s figure . Presume you are taking that over the steepest part of your speed/time chart for 2-3 seconds ? Or is it over the whole pull ?
Was just curious to see how my numbers would compare as it looks like we have identical 3rd gear ratios ....

It's not absolute peak, but close. I generally take the delta RPM rate from 5,700 to 7,200. Any lower and boost might not be up from a gear change, any higher and I may have shortshifted....

With a 4.44 rear end gear ratio, 26.2" diameter tires, and 3rd gear ratio. It works out that 3rd gear is almost exactly 0-100 mph (it might be a bit higher but for ease of math I go with this) from 0 to 8,000 RPMs.....

So extrapolating from that data every mph through 3rd gear is 80 RPMs....

So if I gain 800 RPMs/sec from 5700 to 7200, all I simply have to do is divide 800 (rpm/s) by 80 (rpms per mph) and you are left with 10 mph/s.

I have used this method give me and idea of whether in picked up power from any changes I have made during my street dyno pulls.

When i hit 97 mph in the eighth mile I was at about 10.35 MPH/S. So at 10 mph/s my guess is I would hit 94ish in the eighth mile and maybe 119 in the quarter as it sits.

I have been as high as 11.6 MPH/S but i believe that was in cold weather, 25+ psi, and maybe open wastegate..

I find it as a good method to track tuning progress....

Ok , I've been using virtual dyno to do much the same thing . Just had a look at one of my runs at 15psi on E60 from 5000 through to 7500. Same 3rd gear ratio as yours with 25.8" tyre and 58f ambient temp . Comes back at 10.1mph/s after accounting for tyre difference . Virtual dyno for same run shows just over 400whp and 300ft/lbs.

Its the only method I have since I don't have virtual dyno. It would nice if Adaptronics gave you something to gauge performance.

Looking back at my logs from winter (low ambient temps) when I had an open gate, you can see how much better power was on the motor. This was 11.89 MPH/S through 3rd gear (951/80), which is about 62-88 mph in 2.5 seconds. This was on E60, 21-24 psi, and almost maxed injectors.

If I can't get close to this with a recirculated gate and cooler temps, I am going to have to figure something out. Not going to upgrade to a full 3.5-4" exhaust for this turbo.

https://cimg7.ibsrv.net/gimg/www.rx8...4c32151aba.jpg

Another method I've used is to just overlay either the speed or rpm chart from one log to the next . If you scale it up you can see clearly exactly where you have made a gain or loss . Works better than VD IMO.

Well E35 vs E60 and cooler vs warmer ambient is going to result in some of those differences. All that water might be quenching things down a bit too far. If the fuel ethanol was higher you wouldn’t need as much auxiliary injection.

I put it down to superiority of the Renesis .................................................. .................................................. ................................:p:

:rollingla

I think you are right, I dialed back the water/methanol to about 900 cc/min from 1,200 cc/min, and with a 20.7-22.6 psi pull and 85 degree ambient temps I was able to acceleration up to 11.4 MPH/S in 3rd gear. Then I got stuck in traffic and hit a water temperature cut I have set at 215 which limits my RPMs to 3,500 (don't even remember setting this cut). I began flame throwing on the interstate on-ramp trying to get my speed up above 70 mph in 5th gear. Scared the hell out of me and everyone else behind me. The high speed fans must have just kicked on because this happened for about 15 secs until the temp dropped a bit and I was able to speed up. Needless to say, I have moved the cut up to 225 F. Need to get some more runs in. Too much traffic and heat tonight :mad: Did get an E85 run in so i'm up to 53% and have an extra jug in the garage.

Also ordered a new flex fuel sensor. Seems to be spiking around more and more.

woot, woot :)

Well folks 3rd gear is no more :icon_tdow. 4,700 RPMs and 20 psi and 3rd gear just let go. Trans always shifted perfectly. The torque just exploded it and I could here all the teeth popping around inside of the case. It never ends lol. Was able to baby it home with 1, 2, 4, and 5... I got a spare FD trans in my garage, I will just need to swap the bellhousing right???

On the bright side it did give me hundreds of trouble free pulls until today...

You can see on the graph when the RPMs go straight up when it blows....

Funny thing is yesterday I hit 26 psi and boost cut twice and had no issues.

https://cimg2.ibsrv.net/gimg/www.rx8...bb001a853a.jpg

You’ll need the 5-spd RX8 bellhousing, which was never imported in the US. However, Mazda Motorsports imported and sells it new for $311. Since it never was a USDM part anyone can buy it as a Motorsport part. You have to be a qualified racer/member to order USDM factory parts.

It’s called a clutch cover rather than a bellhousing though; part no. N317-16-210D

occasionally you can find an imported used RX8 5-speed whole for that price online though. I haven’t looked lately b

Stroker, Sorry to hear..., but glad you have a backup. On a positive note ... nice that the engine sustained the boost.

Well the blown trans is the 5 speed rx8 trans (imported one a few years back) so I will just swap bell housing and rewire reverse and natural switches, I believe they are the same as the fd....

I just hope this fd trans I've had in the garage isn't junk. It came on a blown engine so I would assume it's good.

Well I just pulled out the FD transmission and the thing is much longer. I assume that the tailshaft section will need to be pulled from rx8 5 speed trans aswell?????

This is a comparison of the 6 speed rx8 trans next to the FD rx7 5 speed tranny....



https://cimg3.ibsrv.net/gimg/www.rx8...2864c8bd3f.jpg


Update - Stripped the FD transmission down and it looks like it might all work. This is the FD tranny next to the rx8 6 speed to measure overall length...

https://cimg1.ibsrv.net/gimg/www.rx8...66b59fcffd.jpg

Sorry, you’re right. I forgot about that. It takes both the bell & tail housings, was detailed in the thread I linked previously.

Stroker, Kudos, man! You waste no time... :icon_tup:

So I have been doing a lot of reading on these transmissions. It appears that 3rd gear is the weak link. Supposedly (and let me know if i'm wrong), 3rd gear is right in the middle of the case and when you exceed a certain torque level the main shaft actually flexes which causes the gears on the main shaft and the counter shaft to pull apart. When this happens the ends the teeth on each gear start to eat each other away instead of mesh normally. You can imagine in 3rd gear how fast these shafts are spinning and they basically destroy each other in milliseconds. I'm pretty sure this is what happened since 3rd gear is gone and I can hear the teeth popping around in the case. From what I read on rx7club, this tends to happen at 450 torque. I don't think I am putting out that much torque. However, that figure is on a lighter FD and I have a rx8 with grand touring package with a turbo manifold that weighs like 16 lbs, full air conditioning, etc., and i'm no lightweight myself (could easily be pushing 3,300-3,400 lbs full weight). So really I bet that number would be much lower on a heavier car. I guess I have to rethink the whole EFR9180/3.5" exhaust upgrade. The only real solution that seems to give you more breathing room is doing a liberty transmission shaft upgrade and cryo treating the gears, which appears to be like a $2200+ service plus shipping........ Lucky I got this FD tranny free with the core motor I purchased..

Anyone have any other ideas that won't be so expensive??? Maybe ramp the boost up later???? Run street tires as a fuse??? Strip the car of as much weight as possible???

Obviously not beating on the car would be the easiest fix, but whats the point of that?

Absolutely ...torque is the killer not whp so the flatter the torque curve the more whp you can run without blowing s**t up !

it won’t matter how flat it is if it exceeds what the shaft or teeth can handle

a stronger gear-set or trans is the answer, imo there isn’t really a cheap fix except to turn the boost down

sort of the same reason 2nd shears off the 6-spd RX8 box; combination of case/shaft flexure and then the countershaft gear OD is so small that they cast it on the shaft and machine later. Just not enough material there to take the abuse loading.

Just a little update as I haven't posted in a bit. I am in the process of moving, and since the 8 can start, run, and drive (less 3rd gear) I have just left the transmission in until after the move is complete. Once I get into my new 3.5+ car garage (30' x 25') I will really be able to spread my shit out and do some more work without playing musical cars.... I lucked out on this new place as the previous owner was a classic car collector and the floors are already epoxied and there are several 220 volt receptacles throughout the garage for welders, etc. :yesnod: