I may be able to make this claim, but as you pointed out it's a pretty damn limited pool. Haha. Fastest track white hardtop FD based out of Ohio!

Plenty of struggles with the twins documented in this thread. Between this car and my old car I'd say I've been through 5-6 sets of used turbos over the years. The primary issues are:
1. The secondary exhaust gasket (bigger one) fails between the manifold and turbine housing
2. The turbine housings get worn away with heat and will crack and either cause gasket issues (see #1) or like the last set the wastegate would no longer seal
3. They get tired and start either blowing oil smoke out the exhaust (more common) or blow oil through the intake pipes
4. The catch can situation sucks, but I've finally got it manageable

I've contemplated going single for a long time and used to think it was the answer to all of my troubles, but the more I observed others who tracked their cars with singles it's not quite the end-all solution I'd like it to be. For external wastegate cars I hate the fact that it's 2 more things to fail on track and don't want to deal with it. They also seem to crack manifolds and lose gaskets about as much as I have problems with the twins. I thought the internally gated EFRs were the solution, but Peter and others have shown that they have troubles maintaining appropriate boost levels.

Finally there's a big question mark on how much power the FD drivetrain can handle without just going through components at an alarming rate. I've already proven hard tracked cars at lower power levels will kill transmissions and differentials with time and heat. The coolers are helping that, but going up another 50+hp is going to really push those boundaries.

All of that leads to a questionable cost/benefit to going single. For me my supporting components are maxed out already. I'd need a fuel system upgrade including injectors, rails, lines, and maybe pump, intercooler upgrade (in the works, but the one I bought got damaged), most likely a clutch would be needed too. Put all of that together and going single represents a big chunk of change. And what would I get out of that? If I think I need to limit power to 375-380 to keep the rest of the car alive then it's less upside for that cost too. I think there's more value to be had in doing a better LSD, suspension upgrades, or other setup changes.

That being said...as I unloaded the car off of the trailer from VIR I heard a new turbo gasket exhaust leak. I think that the long time on throttle there and places like Watkins just kill things with heat. Rotaries have high EGTs anyway, but being full throttle that long just makes things that much worse. So my turbos need to come off the car anyway and I'll be faced with this decision again over the winter. I'm thinking about a half-step and doing a secondary injector upgrade with rail, putting in the M2 Large intercooler I got, and having Banzai tune the car for more like 14-15psi on the twins and see if I can get 350-ish HP out of it. Then I just may maintain that.

Ah I must have missed the part about the twins as i was reading from my phone. I had all of those issues except for catch can when I had twins. I've been single for like 3 years now and for some reason I keep thinking about going back to twins. Something about a stock engine bay and working sequential excites me now for some reason.

You ever thought about getting new twins instead of used ones?

@#$%ing amazing lap times.

FYI, I don't think the catch can situation really improves with a single turbo, the biggest thing is the intake temps. I understand you're running WI though, I never tried it. What tires did you run?

Hope to see you next year, I'm going to follow your path on diff/trans coolers. And FYI, I confirmed (and ordered) the Liberty main shaft fits FD transmissions.

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Thank you sir, I appreciate it. I'd definitely like to hook up at Watkins or VIR in the future. Or if you and Fritz feel in the mood for a road trip I'm at Mid Ohio all the damn time..haha.

I'm currently running a Water/Meth mix at about 22%-ish methanol. I'm hoping when going to a bigger intercooler that I can go back to just water for simplicity.

I ran the Nittos (NT-01) for 4 sessions and then ran the Pirelli DH slick scrubs for the other 6-ish sessions I got. People who've used both say the Pirelli sticks similar to a Hoosier, but in my experience the Pirelli performance doesn't fall off quite as much over its life until the very end. I've never used Hoosiers to know directly though just going by what others have told me about their characteristics.

That's great news on the Liberty shaft. PM me a price for it if you don't mind please. Are you going to have them do anything else for you like surface treat the gears?

No, as someone else pointed out there are other solutions. They all have their ups and downs so it's up to you to decide. I like the simplicity of the Hydramat and it works as well as I could ever need. The question will be longevity as some people say it'll last 3 years, others 5. If it's 5, that's still a pretty good investment in my mind. Also note that if you're not running sticky tires and are running something like the NT-01 that just going to the later style cover on the in-tank sump got me pretty good performance on those tires.

Fuel levels depends on the track and length of sessions. For instance at VIR I was running 30 min session when we went full length and if I ran hard all 30 mins I'd use about 10 gallons of gas!!! So I had to go out with 1/2 tank. When I'm at Mid Ohio and running 20 min sessions I can go out with 3/8 tank and make it back.

I also thought I'd give an update overall on the differential and transmission coolers. I knew my setup wasn't going to have monster cooling ability with the small cooler cores and limited air flow. It's a compromise based on packaging/space. What I do feel it does is help those components keep their temps from going out of control and having fluid breakdown. I guess I'll see over time how that pans out. More cooling is always better, but it'll be up to you to decide how you think you can get more cooler size or airflow through the system.

I have been very happy with the performance of the Mocal pump with the brass gears. I will say they're reasonably loud, but they should only be running when you're driving hard so that's not really a concern. They seem to have held up to the use well so far.

When I went into the cooler project I figured that the differential needed a cooler before the transmission because of the lower fluid capacity which is why it was done last season and the trans was done this season. When I put them in, I wired LED lights up to my roll bar that I could see in the rear view mirror to know when they had turned on (can't hear the pump when at speed). What's interesting now that I have both done is that the transmission cooler turns on NOTICEABLY sooner than the differential. Even with the car completely cold and going out for a slow session first thing in the morning, typically the trans cooler turns on about 1/2 through the session where the diff cooler might not even come on at all. Once things are warmed up that just happens sooner with the trans cooler coming on after 1-2 hard laps and the diff cooler coming in later. Some of that is because the temp sensor is right in the pan of the transmission whereas the diff temp sensor is in the line coming from the drain/feed on the diff cover. I'm not sure how much of a delay in fluid temp reading that causes, but it still seem to me that the transmission is in need of a cooler as much or more than the differential despite the fluid capacity differences.

I've also found myself coming back to the pits and whenever possible leaving the car idling for 5-10 minutes to keep the diff and trans coolers running in hopes of maintaining longevity of those components. It sure doesn't hurt the engine and cooling system to do so either. A good practice if you can. I will say that even during that idle time very rarely have the coolers ever fully turned off. My temps sensors turn the system on at 190F and off at 170F so I think that also speaks to how hot the components and system stay and why I say my system isn't taking massive temp drops out of the fluid.

Believe the boost issues with the IWG EFRs are attributed to the 8374 with a free-flow exhaust. Have you looked into a 7670?

https://www.rx7club.com/ir-performan...sults-1122815/

The chart seems to be perfect for a stockish road coarse FD without overly stressing the driveline componants

I am on the fence between the two and right now am leaning towards the 7670

It's an interesting option and for sure fits the power goals. I see that most sellers of the EFR kits all suggest the 8374 for track use though. I figured it was due to more free flowing exhaust wheel for less back pressure and EGT as well as being able to achieve the desired power levels with lower boost and therefore less strain. That being said if you can't keep the boost to the desired level it all goes out the window. I think that 87FCTurboII is the only one I've seen lately tracking a 7670 and he hasn't reported EGT or manifold issues so maybe it's all conjecture, but I'd like to see others try that out.

Also, if I'm being picky while I LOVE the mid-range power that turbo can produce, it also falls on its face up top. Even more than the stock twins when looking at the IRP graph you linked and earlier in the rev range too. When I think about my use that could mean more shifts around track which not only complicates things it's more time off throttle!

All of that being said, I've got time to weigh the options. I'm not going single turbo this off season and actually won't be doing many big upgrades. I'm leaning toward doing much less with the car next year and spending more of my time and money on karting with my son and brother. I've already purchased a M2 large intercooler and will be doing a battery relocation I just couldn't fit them in this year so I'll complete that. Outside of that I will most likely keep it simple and just do a couple of Mid Ohio events because they're close and I can do them very cost effectively.

As a former EFR 7670 user I was pretty surprised to see someone use this turbo for track use.

Don't get me wrong, I loved the 7670 on my auto-x/hillclimb/sprint car, but it ran hot on the exhaust side from the smaller exhaust wheel and hot on the intercooler side from always being in boost.
Well, I was running 26psi- so I guess I have to take that into consideration...

Still, for the track I would rather have the EFR 8374 with an added exhaust restriction at the very end of the exhaust (muffler(s) in order to be able to run low boost rather than running the EFR 7670 with the restriction right up at the engine exhaust ports.

I just don't see where you ever need that 7670 boost advantage over the 8374 from 2,000 to 2,500rpm on the track.

Dual parallel EFR 7163 should be pretty nice at the track using the v-band flange available with the IWG for a very simple bulletproof exhaust manifold(s). Would also have lots of exhaust wheel. On parallel twins you add the A/Rs together to get the overall A/R so the dual 0.85ARs would be like 1.70AR on a single!
Might be a bit doggier than 8374.

In my normal fashion it's been a while since I've updated this thread. After VIR last year I got the car home and cleaned it up before putting it away for the winter. As you can see it was pretty funky with rubber all over it and the back gets coated with fuel/premix/funk from the exhaust

https://live.staticflickr.com/65535/...2e951957_z.jpg
https://live.staticflickr.com/65535/...7a7f0015_z.jpg

I also picked up a chip in the windshield either at the track day or on the tow home which is annoying.
https://live.staticflickr.com/65535/...0d296768_z.jpg

Got it polished up and a few coats of AMMO skin on it
https://live.staticflickr.com/65535/...39a18117_z.jpg

The only bummer is that I confirmed that I came back from VIR with a turbo gasket exhaust leak. So they'll get torn off again....that's a common theme.

I made the decision with my brother that for 2019 we'll be doing limited car track events and diving in with both feet into a full season of karting with the family. That doesn't mean I'm completely ignoring the Rx7, but it'll change use and priorities. I'm planning on doing 2 events this year in the car and both at Mid Ohio to keep it simple and low-cost.

I have a planned intercooler upgrade and battery relocation, but I wasn't going to have time to get to them before the first event in May, so it was just focusing on fixing the turbo gaskets and preparing for the event.

Got the turbos taken off and found the exhaust leak. It's always on the same place, the thin section of the gasket for the secondary turbos. This time though it was on the manifold side that it failed which was interesting. Remember last time I had the turbine housings machined, but only block sanded the manifold? Maybe the issue, maybe not. There was more cracking on the turbine housings than I expected with the "higher nickel content" of the '99 spec turbos, but not enough to worry at this time.
https://live.staticflickr.com/65535/...44f89295_z.jpg

Here you can see the leak on the manifold side. You can also see the damn bolt that broke off in the manifold meaning it was now trash.
https://live.staticflickr.com/65535/...1ba69428_z.jpg

Here's the gasket showing the failure
https://live.staticflickr.com/65535/...7a214f15_z.jpg

I also managed to bake another turbo control actuator to where it'll work under vacuum but leaks under pressure. You can see the plastic deformed around the arm and this is the indicator to test it and see if it's done...mine was.
https://live.staticflickr.com/65535/...246607db_z.jpg

I was able to source a new manifold and turbo control actuator. Side-note these things are getting expensive. I also got a backup manifold and I have a backup set of turbine housings and I'll have them machined and ready for go for the next time I'm guaranteed to do this project.

Here are the low mile manifold and turbine housings back from machining...so pretty
https://live.staticflickr.com/65535/...ed822f6b_z.jpg

Also since I keep cooking the actuator I took some spare gold reflective foil and wrapped it all up. Will this really save me headaches of this part failing again? Not likely lol, but it makes me feel like I at least tried to remedy it.
https://live.staticflickr.com/65535/...17a3e6cb_z.jpg

Turbos back together with new crush washers for oil and coolant lines. Got the turbos back on and feeling good about moving the project along....except something looked off about the turbos...
https://live.staticflickr.com/65535/...e314a363_z.jpg
oh, that's right, the heat shield is missing!
https://media.giphy.com/media/nBobpPYmgWc3C/giphy.gif

Had to take everything off and put the heat shield on. Spent an hour thinking i could wedge it in there without doing that, but to no avail. Here's how it should look if you don't mess it up.
https://live.staticflickr.com/65535/...e2e07ebf_z.jpg

Remember that chip in the windshield? Despite being in the garage all winter, the chip turned into a crack...which wouldn't be suitable to pass tech for any HPDE...DOH
https://live.staticflickr.com/65535/...0c0b9fac_z.jpg

Called around and SafeLite was the only company that said they could get a windshield for it. Ordered the grey tint at the top because I like the look better than the blue. Took off the wipers and cowl trim to make it easier for the tech
https://live.staticflickr.com/65535/...fc1f3339_z.jpg

Day of the appointment came and Safelite calls 1/2 way thru my appointment time to tell me the windshield they got is damaged....and it's the only grey tint one they had in their entire inventory....sweet. Luckily they were still able to order a blue one, but I had to wait for it to come in. It finally came in and my mobile tech was really cool. They didn't have an exact match for the windshield trim like they said they would, so he helped us try out a couple ones until we found the best solution. In hindsight I should have ordered the factory trim to have it ready for them to install. Live and Learn. This one is a little bigger, but still the best of the options we had and at least I have a nice new windshield even if it's blue tint.
https://live.staticflickr.com/65535/...b44b83be_z.jpg

Next up for prep was to put in fresh diff and trans fluid. Ordered Neo fluids like I've been running, then got home to find my shipment like this...
https://live.staticflickr.com/65535/...9817bd08_z.jpg
Thankfully the company was great about issuing replacements, but damn was that mess a pain to clean up. I can still see some of the staining on the porch as I haven't had time to borrow a pressure washer to take to it.

Other than that I was using brake pads I already had so I swapped those out, gave a quick brake bleed, mounted the brake cooling duct hoses, wheels/tires and was ready for the first event of the year.

First event of 2019 was at Mid Ohio with Chin Track Days. Weather was on and off for rain just like this whole damn year has been. Thankfully we didn't miss too much time, just had some damp conditions in the mornings with overnight rain, and lost the last afternoon and left early. Still was able to put 200+ track miles on the car though so plenty of time. Car did great no complaints other than you can hear the rear rotors in my videos again. I've just had a bad batch with this set of rear rotors is my best guess as they've given me fits from the beginning. I'll likely replace them this year and keep them as emergency backups.

Had a good run with a newer really well built Mustang race car.

Here's playing around with my friend in the black C7Z from previous videos. Always fun to see how our cars compare. His car has only upgraded brake pads/fluid and runs Michelin Pilot Sport Cup 2 tires. I'm noticeably less power, but tons of upgrades and running slicks. It just goes to show how far car performance has come. Mid Ohio is 1/2 hp track and 1/2 tight and technical track. His power gives him an advantage from the front straight through the back straight. Then my tire/grip gives me an advantage on the back side of the course from the end of the back straight until the front straight. Makes for some fun with me trying to wring the ever-loving life out of my car on the back side of the course to reel in his gap, then he can gap me again on the front side. We ended up running fast lap times within 0.1 sec thru our full run together, we just get it done in completely different ways with our cars.

Here's the short version of just us playing together

Here's the long version of us working some other traffic and he also lets me by and we continue on. Same results, I can gap him a bit on the back side, and he reels me in on the front half. Check on the later laps where you can see him in my mirrors on the back straight and how much he can close that gap!

After the event I washed the car and put it back into street trim (street wheels/tires, street brake pads, remove brake cooling hoses). In doing the pads I could hear something bouncing around in the brake rotors. The good news is that the brake ducting works. The bad news is that it'll catch rubber coming off of cars (like when I'm close to that mustang) and they get in behind the rotors and turn rock hard with the heat and just bounce around there. Not hurting anything, but not helping cooing and sounds annoying.
https://live.staticflickr.com/65535/...61472f67_z.jpg

I also had some pretty big chunks out of one of one of the front pads. They were near the end of their life, but i'll keep an eye out for more of this in the future. Just got them pretty hot it seems which happens with 30 minute sessions. Here's the bogey one and the other from that caliper for comparison
https://live.staticflickr.com/65535/...9887f808_z.jpg
https://live.staticflickr.com/65535/...4d7d9165_z.jpg

I've still got like 2-3 sets of half-used pads that I'll use up in the fall at Mid Ohio. Next event isn't planned until Sept. Hopefully that gives me time to tackle some other projects, but life moves fast in the summer so who knows. I'm also actively trying to drive the car on the street more and put some street miles on it for once.

Some anecdotal data but this past weekend I was using the FD to run errands around town. Ambient temp was warm in the upper 80s, but nothing extreme. I noticed that while blasting around the highway 80-90mph but low load that after 10-ish minutes of that it would turn on my transmission cooler. I was certainly surprised to see that and it took a good 10-ish minutes of easy street driving before the cooler would turn back off.

I think that just goes to show how little cooling capacity the stock trans has and how hot it really gets. Remember mine also has an extra quart of capacity. I wrongly assumed the diff was the weaker link, but I think the trans should take priority when trying to setup coolers for the car. When at the race track I regularly see the trans cooler kick on WAY before the diff cooler, usually it fires up within 2-3 hot laps.

Hey Smokey I love your thread! Just wanted to let you know that you inspired me to get out on track for the first time this year - I've done a few SCCA Track Night in America events with more to come. You also helped me decide on a C5 Z06 for track duty - the rationale being it would be reliable out of the box. That hasn't proven to be true, a lot has gone wrong, but I'm having a great time with it. There may still be an FD in my future, though. Keep up the good work and thanks for the inspiration!

Thanks for the reply and that's awesome to hear! Welcome to spending WAY too much money on a hobby..haha. I've worried that now that C5Z's have gotten older if they'd have problems with just overall age of components and the car. I'm guessing it's very important to buy one well kept to try to avoid that as much as possible. That being said it's still a great platform and I hope you have fun with it.

And best to have backups :lol:

https://cimg7.ibsrv.net/gimg/www.rx7...05a9bc0a46.jpg

Yup, I think the trans is the weaker (and more expensive) link. I started to see fluid weepage on my diff from hear, and switched the fluid to Amsoil 70/140, and no issues thus far, runs the same. I'm currently upgrading the trans with Liberty main shaft and the high-capacity pan, but a cooler will happen as well, especially after spending the cash on it.

Amazing progress, one hell of a thread to read through.

What pads are those?