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Old 10-29-2012, 04:36 PM   #41
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Be sure to vent all possible leaks clear of the pan, consider a bulkhead/drainage for the fuel bladder should it rupture in a crash, and be sure to put in access panels to clean/ wipe down seepage should it occur around the trans/diff and cooling lines.
The exhaust also needs attention in it's own right, try to avoid cracks, flanges opening etc.
A small stream of exhaust can make havoc when it has nowhere to go. Heating the tank from below is not a good idea.
V-bands and some flex units could never hurt I guess. Routine inspections are more difficult but also more important...

My friend (who's aero I've posted pictures of somewhere) managed to ignite one of the exh hangers due to flange bolts getting loose.
A small fire just below the tank is not a nice thing.
His face turned a bit pale when I made him feel the temp of the tank (20 minutes after the fire was put out)...
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Old 10-29-2012, 05:34 PM   #42
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For what it's worth (and that's approximately what you have paid me for it), we were constantly having to repair or replace Dzus fasteners when I was an assistant crew member with the old spec Barber Dodge formula team. Granted, the body work came off a lot more frequently than an undertray might.
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Old 10-29-2012, 11:48 PM   #43
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gtred - why did you trans and diff overflow??
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Old 10-30-2012, 09:20 AM   #44
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^ Of course, extra fluid will have to be added to make up for the coolers and line sets. Were your cooler feeds in the upright position? When I assemble mine, the feed fittings will be upright to help prevent that. I would *think* the pump would do a good job of acting like a check valve from it all flowing back in the units, causing your over-filled situation. Close?
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Old 10-30-2012, 02:42 PM   #45
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It had to do with where I aimed the discharge line. I don't remember now if I had the oil stream landing right on the gearset, which caused misting; or if it was some other issue. Tech support at Jerico helped me sort this out; apparently, there is a "preferred" placement for the incoming oil line.
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Old 10-30-2012, 08:49 PM   #46
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Does anyone have any ideas what kind of temps the diff is seeing in general? I'm looking at how much it might cost to put together a pump/cooler/lines for the diff. The Mocal pump I found is good up to 300 degrees but that sounds low to me..?

-Ryan
I've been trying to find this out for a while, but never found it... I went ahead and covered them up anyway. My undercarriage is similar to the GTRs where there is s huge gap in the middle-- I only sealed off the rear part, so air doesn't stagnate around the rear subframe area. I experimentally added 2'x3' piece of coroplast under the tranny, couldn't get IR temps from it, and the coroplast only melted where it was in direct contact wth the OEM header before the cat. It lasted 2-3 track days before getting snagged on some railroad tracks.

On the rear, I cutout the coroplast around the midpipe, less than 1/2" between, and it showed no signs of being close to melting-- this was for over a year of DD and a few track days. It's still on the car as we speak.

I got an IR reading of the differential from a 30 minute daily drive, it was about 170 degrees... I was sure it was the diff casing because if the IR beam hits the exhaust pipe, it was much hotter (obv)-- but my IR reader reads to 220~230 degrees and on exhaust pipe it just reads "HOT."

I never remember to check diff casing temps after a session, let alone tire and brake times.
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Old 10-30-2012, 10:35 PM   #47
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Now I'm wondering if it's worth wrapping the downpipe and catback up to the muffler to control exhaust/diff temps.. how much wrap are we looking at if this is done on the average setup though?
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Old 10-31-2012, 12:33 AM   #48
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Default Goodwin's undertray

I talked to Brian Goodwin today at SEMA about his MX-5 flat bottom and cooling, and he said he's got venting to the transmission and the differential, and he's had no apparent heat problems with either. He has revers NACA's (if I recall correctly), and runs hoses that direct air at the pumpkin.
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Old 10-31-2012, 09:41 AM   #49
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I was thinking of starting the same project after I get back from Afghanistan

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Old 10-31-2012, 01:12 PM   #50
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Now I'm wondering if it's worth wrapping the downpipe and catback up to the muffler to control exhaust/diff temps.. how much wrap are we looking at if this is done on the average setup though?
Heat wrap is not a good idea in a race car. Not only will it cause metal pitting and cracking, it serves as a sponge to soak up flammable material like oil, gas and brake fluid. I've has this happen to me twice. I'll try to post a videoclip of my Z-28 explosion. The engine failed on the backstraight and sprayed oil onto heat wrap that I had on my fuel rail. The oil soaked heat wrap wicked the fire rearward and exploded the gas tank before I was able to come to a stop. My Video | Facebook

This also happened recently in my miata. The downpipe came loose and melted my dipstick pull-handle off. The resultant oil spray collected on my heat-shield wrap for my water lines and caused a small fire. I've learned my lessons: Metal shielding only in a race car!
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Last edited by gtred; 10-31-2012 at 02:43 PM.
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Old 11-02-2012, 03:47 AM   #51
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Quote:
Originally Posted by cordycord View Post
I talked to Brian Goodwin today at SEMA about his MX-5 flat bottom and cooling, and he said he's got venting to the transmission and the differential, and he's had no apparent heat problems with either. He has revers NACA's (if I recall correctly), and runs hoses that direct air at the pumpkin.
That's very promising to hear that Brian is doing OK without adding pumps and coolers. It at least makes me feel more at ease with my current plan which is to NACA duct some air up to the diff to cool it and run it that way at Auto Club Speedway this month and see how it goes.

-Ryan
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Old 11-07-2012, 06:51 PM   #52
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Well, just finished fabricating the flat underbody and new diffuser. I'm going to put a NACA duct in to feed air to the differential before Auto Club Speedway in a week and a half and we will see how it goes!



-Ryan
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Old 11-07-2012, 07:47 PM   #53
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Looks good. Nice work!
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Old 11-07-2012, 07:52 PM   #54
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Quote:
Originally Posted by ThePass View Post
Well, just finished fabricating the flat underbody and new diffuser. I'm going to put a NACA duct in to feed air to the differential before Auto Club Speedway in a week and a half and we will see how it goes!



-Ryan
So beautiful... So very beautiful.
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Old 11-07-2012, 11:00 PM   #55
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careful of some off the shelf NACA ducts, make sure they're correctly designed!
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Old 11-08-2012, 02:22 AM   #56
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Well, just finished fabricating the flat underbody and new diffuser. I'm going to put a NACA duct in to feed air to the differential before Auto Club Speedway in a week and a half and we will see how it goes!

[IMG]https://www.miataturbo.net/attachment.php?attachmentid=59318&dateline=1352328 703

-Ryan
Ohhh ACS! I've seen first hand what speed a stock powered (no aero) Miata will reach (and what it can reach when drafting). I haven't ran it, but I'm so anxious to test with and w/o aero there. Did you happen to see anything like that? I kind of doubt it with your turbo but it would be interesting to see!
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Old 11-08-2012, 02:28 AM   #57
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Sorry I'm not following the question.. Have I seen what?
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Old 11-08-2012, 03:16 AM   #58
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The airflow to the diff - where will it exit?
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Old 11-08-2012, 03:34 AM   #59
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The airflow to the diff - where will it exit?
I believe the area above the diffuser is open where the bumper was which would pull the hot stuff out. Can we get a few more pic and angles on that ThePass?
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Old 11-08-2012, 06:38 AM   #60
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Sorry I'm not following the question.. Have I seen what?
Sorry--If your car is drag limited or not. I think it was a NB1 engine in an NA, but it was getting stuck at 130s on the banking... only til drafting a Del Sol did it reach 140s. I know you've a turbo so it might be moot.
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I believe the area above the diffuser is open where the bumper was which would pull the hot stuff out. Can we get a few more pic and angles on that ThePass?
You'd be surprised at what you might see tufts doing at the gap between the bumper and diffuser.
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