Fritz Flynn

iTrader: (263)

Nice write up, glad you found a keeper and how did I miss that one LOL

Over the last 10 years every time I take an FD that I haven't tracked to the track the 1st session or two the gear oil gets so hot it starts leaking from the drain bolt and I have to tighten the bolt further.

With the greddy extra capacity cover I can't get it to seal at all no matter how tight, different screw, threads whatever it won't stop leaking. After trying two different covers I said eff this and went with the stock cover, pump and cooler.

Now when I change the fluid it doesn't come out black and stink up the planet and more importantly I'm not killing diffs.

A cooler isn't an option for me it's a necessity.

PS Nice laps at watkins. It's great to see someone drive this car as intended. Based on those lap times with that setup you will be killing transmissions and diffs so get some coolers and keep that water injection or go vmic.

PSS I took one of my DD cars out for the weekend making about 275 rwhp max (bolt ons only) and ruined the diff in a weekend. Stock wheels with hankook c51s mounted. Had I used more rubber I would have done more damage. My open laps were 2.10s. VIR and watkins are pretty close time wise so you are going to hurt the diff and trans. Trust me.

TomU

iTrader: (11)

Great thread, but all the talk about trashing differentials is making me nervous. I have not had any problems, but I don't run R-comps. I have upgraded to 255 RE-71s. Hope that doesn't kill my diff

BTW, you may want to try more meth as it's the methanol that lowers IATs. Water reduces some, but not as much as methanol.

jacobcartmill

iTrader: (6)

very nice thread!

serious work, good documentation, quality work to prep for the track, and track videos. you made my day.

wutangben

iTrader: (15)

great thread, thanks so much for sharing in such detail!

Smokey The Talon

iTrader: (33)

Thank you. The Nittos I've been running for years are a little less sticky than the hankooks so maybe I was getting some leeway there. I've thankfully not had the drain plug weeping issues. While I'll have a primary Nitto setup next year I'll also be running Pirelli DH slicks for fast stuff so the diff issue may become more severe at that time. Any guidance on what you've done for pump, lines, cooler, and mount/location?

Smokey The Talon

iTrader: (33)

I've been using/diluting boost juice and playing around with concentrations all the way up to the 49% meth it comes. It does help temps more but the gains aren't linear. I find the 23%-ish gave me the best bang for the buck.

Thank you, I've definitely enjoyed your threads and wish you luck on your latest one.

Thanks. Hopefully others can learn from my ups and downs. I've picked up so much from this forum from people like Fritz and Peter who have tons of track experience with these cars that I hope I can pass that to some others as well.

Fritz Flynn

iTrader: (263)

I am not a mechanic so I let pros handle coolers or anything outside of bolt ons.

Trans cooler is mounted in the rear sub frame. Typical AN lines with a tilton pump

Diff cooler is mounted on the top side of the rear diffuser. Which is not the best spot but not much room back there with the exhaust, gas tank and one pump/lines already mounted.

The diff and trans just like the turbo and every other wear items is a direct relation to lap times. Once you are running consistent 2.10 laps and below at either VIR or watkins glen IMO it's time to upgrade and cool the drive line.

I've never driven watkins but my car did an easy 2.02 (it runs 2.05s limping/something broken which is the majority of the time on old rubber LOL) at VIR in 90 degree weather and Pete does approx 2.05s at both tracks. Pete doesn't have coolers but if he ran on a regular basis I believe he'd be replacing both trans and diff after say 10 or 20 events.

Smokey The Talon

iTrader: (33)

I guess we'll see what happens with slicks! haha. For now my mitigant is to change the fluids quite often.

While we're on the discussion on diffs, and the car is put away, and I'm bored...is there any evidence/proof that an aftermarket diff would take the abuse better without failing? I'd tend to think that a clutch-type would actually create more friction/heat than our torsen, but haven't found anything definitive. Supposedly gains to be had performance wise by going to a well setup clutch type, but I'm not paying $1,500 to have the same damn temp issue. Is our lack of fluid capacity the core issue?

Before anyone brings it up, I'm not looking to do a Cobra 8.8 swap.

Fritz Flynn

iTrader: (263)

A clutch type diff is just smoother (so likely puts down power a little better), less hopping etc... when sliding around. I doubt the temp difference is much of a factor they both get too hot. I'm also perfectly happy with the stock torsen but prefer clutch type all things considered.

ZoomZoom

iTrader: (2)

Besides Fritz there are guys with LS swaps that road race and they have the same issues with a stock diff, the added fluid from the Greddy cover helps some but under severe load it just can't keep the temps down a cooler is a must even for guys with Ford IRS swaps. Even fresh gear oil is cooked in a session and it's puking out the breather.

Fritz is also right about the Greddy Diff covers leaking. The expansion rate of the aluminum cover doesnt seem to stay sealed to the housing. Someone on Norotors said all the covers need to be milled down a bit on the mating surface to be trued. I have no experience with it myself so the obvious cure is the cooler for temps. As far as leaking... you can always test the theories.

The water meth is nice. From all the research I've done the 80/20 water/meth is a good compromise. The water will decrease combustion temps so your EGT will go down and the Meth will cool the AIT. Meth is also a fuel so be careful of experiments if you are tuned for a certain mix.

If you ever plan to run at New Jersey Motorsports Park let me know. I will see what I can do about getting some nice pics of you on track. I'm no pro but sometimes I get lucky.

Mike

Smokey The Talon

iTrader: (33)

Thanks for the input guys. Sounds like I should start researching diff cooler options and see what I might be able to do there.

Mike your photos are awesome and you know it! Haha. Not sure if I'll make it to NJMP but will be going to Watkins again for sure. Next on the list is either VIR or Road Atlanta for another longer trip. Our local PCA chapter puts on a good event at Indy as well that I'm interested in. I'm also looking to get to the updated Pitt course as I haven't been there since they opened the south course. Who knows if/when I can work all of those in. I'll likely start 2017 in May at Mid Ohio. Being able to try out new setups and shake down on a track I've been riding/driving on for 17 years and is only an hour from home makes a lot of sense.

Fritz Flynn

iTrader: (263)

I'd love to see hard data on water, meth or whatever I can inject to significantly reduce my exhaust temps.

If it works well I'll definitely consider using it. However my understanding is the only way to get exhaust temps down outside of tuning is a fuel change.

Both greddy covers I had leaked at the drain bolt hole itself. PFS tried everything including retapping and using a tighter thread etc....

Fritz Flynn

iTrader: (263)

If you make it to VIR please let me know and I'll try to be there

LargeOrangeFont

iTrader: (7)

With regards to the diff, you can put your own cooler setup together for under $600. You will absolutely need a pump to make it work. The more grip you have the hotter the diff is going to get. I would run the setup on a switch and just let it run while you are at the track. Driving a car on the street with a diff cooler pump running all the time is annoying. It's nice to have the option to turn it off.

Wrap all of your exhaust with header wrap where it passes under the rear subframe. This will drop diff temps 10-20 degrees. A Torsen style diff does run cooler than a clutch style diff by 10-15 degrees in my experience. I like the Torsen style better, I can get back to the gas sooner on corner exit than I can with a clutch LSD. I also run a remote catch can for the diff instead of the breather so it never pukes all over the car, hot exhaust, or the track.

The high diff temps in FDs are a result of the exhaust passing right next to the diff. I have an 8.8 in my FC, and the highest diff temp I've ever seen is 240F on track. The exhaust in a FC is routed further away from the diff.

Fritz Flynn

iTrader: (263)

Good info regarding the exhaust. I need to wrap mine

Are the lap times in the FD and the FC the same?

Smokey The Talon

iTrader: (33)

I wish I had EGT data from my setup with water and now water/meth to be able to share. What I can share is just from my experience:

First, you're correct it's a bit of a bandaid in that my PFS intercooler is too small for 20-30 min track work. I've steered away from changing anything materially (injectors or v-mount like desired) from my current setup as I didn't want to retune the car as the closest person I trust to do that is Banzai.

Water injection on its own isn't going to do a lot for intake temps but I found it would keep them from skyrocketing (staying more in the 50c range or below). Also, should IATs rise, the water keeps the motor from detonating and has served me very well in that regard for a long time. As people have mentioned where water does its work is in the combustion chamber where it reduces combustion temps. it's been shown to reduce EGTs in diesel's, but I'm not sure that I've seen tests showing the same on our cars. I can say that running water on top of your current tune will make the car run slightly more rich which as you pointed out is similar to dumping more fuel to reduce EGTs.

Methanol is better at intake temp reduction and this year I saw that running a bit of meth (about 22% by weight or 25% by volume) helped me keep intake temps even lower (40-45C) without making the car run too rich. You don't have intake temp issues so you don't need that portion.

It's been on my list for sure. I'd probably go to the fall event with NNJR if I can manage to keep enough funds in the car account that long into the year..haha. I'll definitely give you a heads up so hopefully you can show me the fast way around.

Good point about the exhaust mine is definitely millimeters from the casing. I wonder if I can get just the pipe (not the can) ceramic coated like my downpipe.

I was wondering how you guys run a thermostat for the rear cooler. Sound like you don't and run a switch? My only concern there is that it's one more thing for me to forget to do. I thought about running a catch can for the diff, but didn't want to place it in the cabin and there's pretty limited space elsewhere down there.

Fritz Flynn

iTrader: (263)

I know I'm beating a dead horse but without WI you'd see 60c plus AIT with most any SMIC which is blow your motor temp and getting it down even 5c while on track is HUGE!!!!! so WI is VERY good at controlling AIT/detonation

I think you'll find once you have a nice VMIC you won't need to bother with WI but since you already have it then why not.

Yep I have one switch which turns on both the diff and trans pumps. The trans cooler is actually more important IMO because the trans is harder to change, usually more expensive to replace and probably dies sooner overall.

I'll reiterate that hurting your diff and trans is a direct result of how fast you are going which is why I was curious if LargeOrange is running similar lap times in his FC versus his FD.

As mentioned earlier 2.10 laps and lower at VIR and WG is about where things start to heat up. I'd say 1.22 and lower at Summit Point.

ZoomZoom

iTrader: (2)

LOF has an LS1 swapped FC. I wish he would get an FD but don't think he has one yet.

Btw just wrap the exhaust. You don't need to send it out for ceramic coating.

LargeOrangeFont

iTrader: (7)

Dont waste your money with thermal coating. Just get some black header wrap. I know there is limited space under an FD but you don't need a large can. A long loop of hose will even work. You just want some excess volume in case the diff pukes due to heat. The extra volume will contain the fluid and let it drain back into the diff. I used a catch can for go karts. It is pretty small.

For the cooler you can do a couple things, but I would not bother with a thermostat, as it could wreak havoc with your pump. Some guys use a thermostatic switch to turn the pump on at a specific temp, but most run a switch.

The other option is to add some ducting, to get some fresh air up there, insulate the exhaust, put on a catch can, monitor the temps and change your diff fluid after every track day. I did this for quite awhile.

You can run a temp sender to your diff and (I assume you have an oil temp gauge already) and you can put a switch on the sender to switch between engine oil temp and diff temp if you do not want to add another gauge.

You may also try running 75W140 gear oil if you primarily track the car. It will hold up better to the heat.

LargeOrangeFont

iTrader: (7)

I thought about buying your old white one...

But yes I just have an FC. I have extensive experience with diff temps and how to reduce them from my days running a Mustang Cobra quite a bit on track. I was prepared to use all of my knowledge on my FC when I finished it, but low and behold.. I have no diff temp problems. The diff sits low in the car and gets some fresh air, and the exhaust is a 5-6 inches away on both sides. I change the diff oil after about 25 hours or on track.. To my surprise, it's looked fine twice now.

AudiOn19s

**big brother here** - I've enjoyed reading your input both here and Rennlist. I'm pushing Chris (Smokey) to explore options for coolers this off season as I agree the issue is only going to get worse. Our home turf at Mid Ohio isn't as fast as other places and is pretty easy on equipment. The more and more we travel to long distance venu's the more we find additional issues that need addressed.

Based on what we both run on nitto's vs. what I run on used DH's...his FD will easily be a 2:03-2:04 car @ WGI next year on good rubber and with a little more seat time at that track. I couldn't believe the time difference for my car there when I switched to good rubber.

Fritz Flynn

iTrader: (263)

NICE! Can't wait for the videos

I find hoos are worth about 4 seconds vs say 888s at VIR so seat time is essential and he will definitely break everything LOL

Smokey The Talon

iTrader: (33)

Well, now that Audion19s is here, the true goal of this project is revealed...compete with his GT3. I want my FD to be an overall nice car, be fast on track, and be reasonably reliable on track. That's a tall order when it's always being directly compared to his 996 GT3. You'll notice the video titled "cold air helps power but does nothing for slicks" that's his GT3 I'm chasing. Nothing crazy on the build, but well built/developed and very well driven.

Will a FD ever be a Porsche when it comes to build quality?...no, but it doesn't have to be a rat either.

Will the FD ever be as track reliable as a GT3?....that one's tougher!. Outside of the water fittings the GT3 is pretty damn reliable. Even when my FD doesn't break anything I'm still always "tinkering" with it during events (GODDAMN CATCH CAN).

Will the FD be as fast as the GT3? I think that can be done, but it's not easy. It's already faster than most GT3s I've come across on similar rubber and even some on faster rubber (red 991 in before video as a point). His GT3 car/driver combo always stays ahead though, so I'd like to close that gap. It'll be interesting to see if the square wheel/tire setup makes any difference on Nittos (about 1-1.5s gap now) and how they compare when both on slicks.

SO...if a diff cooler is the first step toward reliability then I'm open to try it. If the diff works well, then I can consider a trans cooler. Then if I ever get the car fast/sorted at the current power levels with slicks...then I'll start the whole process over by trying to go single turbo! haha....or cheat and buy a C6Z.

Fritz, I know you dabble in both worlds so I'll rely on your help to make the FD victorious...without being stripped and single turbo like yours..haha.

ZoomZoom

iTrader: (2)

I love posting in this build thread so I won't stop now. Fritz has spoken about his comparisons to his GT3 previously but I'm not going to steal his thunder.

My opinion is that the rotary engine is actually more suited to the race track. Most race teams who have raced these over the years will tell you that they usually got entire seasons out of their motors racing in IMSA while the piston motors of the competitors were getting changed out considerably more often. Rotary engine failures seem to be caused by some sub system failure that causes an engine failure and never is an issue of wear.

Like Fritz also said is that you will break everything. That GT3 is expensive to run on track also. A shop near me works almost exclusively on Porsche's and suppprts a lot of race cars. When the owner told me what it costs per hour to run a GT3 over a season..... I realized the Mazda was the only way someone like me could track a car. I'm speaking on a hobby level and not competitively.

That Porsche shop was nice and did a great job corner balancing and aligning my LS3 swapped CW FD. Cross weights were within a single pound.

Will you be as fast as the GT3? I have seen all levels of driving and it doesn't matter nearly as much what the cars are capable of. I've seen many an inferior car run up on something it shouldn't.
"Scrub" here on the club has posted video in the past of him following a GT3 all around the track over here on lightning here at NJMP. He has a twin turbo FD running 12lbs. Last time I saw his silver FD it was sporting Victoracers.
Maybe he will chime in about it. Maybe stoke the flames of the brotherly rivalry lol

GoodfellaFD3S

iTrader: (213)

^Scrub runs a T04R at quite low boost, 12 psi sounds right..... just not twins