So if a flat floor was added what would be done about the exhaust heat? I keep seeing that wraping is a bad idea and there is going to be a lot of heat under there. most cars you see with a a flat underbody are mid engined so it's not as much of a problem.

re-read post #42

https://www.miataturbo.net/showpost....3&postcount=42

wrapping the exhaust cant be good for it... spoke to my exhaust builder and he said it will destroy the exhaust quickly. also another customer of his enclosed an exhaust and melted the intercom and lots of wiring inside the car from the extreme heat.

If you have a good front bumper, splitter and undertray to sub frame why would you not try to clean up the rear exit portion some? I understand the middle of the car has imperfections that cause the air to tumble in places but does that mean none of it is laminar? Assuming that some of the air is laminar and some turbulent what would you suggest doing to rear sub frame, spare tire pocket and bumper if anything?

I build most of the custom exhausts we do. I wrap the exhaust anywhere I need to control heat in our race cars. Never, not once, ever has one failed or been destroyed by wrapping it. I think you need a new exhaust guy.

the guy is a top exhaust builder though.. cant understand why he would say that if it wasn't rite. has anyone on here wrapped a full exhaust with no negative consequence over an extended period??

A good underpanel can be used to vent out exhaust heat. Use a well placed NACA duct and louvres to vent out the heat.

ok fair enough. some people post when they drink, some people want stir the pot, and some people are just very opinionated on the inner tube. try not to take personal offense when posting something unconventional gets some heat. post some evidence and all will be well. I've gotten a little annoyed at times but I bet if I met the "offender" in person I'm sure we would get along just fine. just say'in.

I think some of the criticism you've gotten has some merit but what do I know, not much about rear diffusers for sure.

people laughed under their breath at my oil cooler duct and under tray at the track this weekend because it was not a fancy carbon fiber store bought "recognized" mod, whatever, I know it is affective. I had a friend wave me down to acknowledge that he saw me having issues because he thinks I'll take off the turbo any day now due to reliability. fair enough, but I don't think I will anytime soon. end vent..;)

I can take it, I know how this place works. BUT It looks like all the bullshit aimed at this guy and his mod that might just possibly work (i completely agree with k24madness above), has gotten such a hiding that he has gone...

What a waste, Imagine if Lightspeed, (Aussie carbon fibre guy) had taken onboard the few early smart arse posts that were directed at him and left, all the cool work and info he provided would have gone too.

Who is to say the NTguyen (the OP) isn't a freakin genius like Lightspeed seems to be and has stuff of value to offer here....

Some times the "old boy" homo erotic, haze till you die atitude just gives me the shits...other times it's funny as hell.

I just think it got out of hand on this new guy is all..

Flame away i guess......

Whose car is that viperormiata? yours? I just got a lotus diffuser and planning to attempt exactly that ^. I would love to get instructions and how to from you or whoever that is. LMK.

I can do a diffuser with <5" strakes and stay in TTB. How can I do this without the exhaust piping burning the car to the ground, and have it still be effective? What if there is a hole for the trailer hitch?

I need a stock front bumper, again, lol. Then I can run a splitter and a wing.

Contact "ThePass" on here, it's his car.

Thanks.

Hey hustler, think about getting a 18" round or oval muffler like the flowmaster hushpower and a turn down at the diff. thats what I got, and is pretty much the Spec exhaust setup for CSP. it comes in right arounf 90 dB. would be quieter if you run a CAT.

FYI, I am running TTD. according to the rules adding a diffuser is only 2 points. Right? that will put me right at the limit of my points budget. so if it gets assessed as more then I might get screwed into TTC. or have to pull it. Thoughts?

Thanks but I run exhaust pipes past the bumper, fire under the car scares me. I also have to buy a smoker, another gun, and another set of tires so I'm not buying ---- for any car.

I've heard that a big-wheel with a Mazda sticker is now TTC. I assume you're NA if you're in TTD or TTC? I don't really know, outside of TTE it seems that Miatas will not be competitive. I'm fighting to stay ahead of TTC cars these days. The gut that usually nips at my tail in TTC has an EVO8 on 255 NT-01 making ~280whp at 2900lb with driver. I'm 2430lb, 225 tire, and limitted to 210whp in TTB.

I'm sure he is fine, he drives a miata so I doubt he really cares what other people think or might think or could think about his car or how he chooses to mod it.

People who take ---- like this personally on the internet are women in prison.

big wheel with mazda sticker? you mean a turbo?

yeah I am NA. and plan to run TTD.

My car is a CSP built miata. I started running time trials with NASA, so I had to dyno reclass because of my swap to an VVT motor in my 96.

My car as is base class is TTE** (+14)
+14 points for my power to weight of ~150WHP and 2300lbs (with me+roll bar+hardtop)
+10 for kook Z214 C71
-1 for 225mm wide tire (235 TTE base tire)
+3 for Torsen LSD
+7 for coilover suspension (+3 shocks, +2 springs, +2 sway),
+3 for R model lip. (Its not factory BTM so it counts as an air dam. Yeah kinda dumb.) I think I am going to rivet more plastic (garden border) to it to make it lower.
+2 add elise diffuser
= 38 points.

can't think of anything useful for that extra point. and its budget incase I get pinged the one point for hacking the bumper cover too. not sure if I need to count that. rules have "add a diffuser" for +2, and another line item replace or modify rear bumper cover for +1. so is that +3 or +2 for me?

I'm not scared away i know how the internet works...also don't care at all what people on the internet say, thus why i have 0 desire to change anything...

I think over all if you go online to justify your mods you'll end up with a car that wasn't built by you.

really so far this is one of the more tame looking cars i have ever built.

The stock lotus/most aftermarket diff users offer a cut out in the center for an exhaust exit.

https://www.miataturbo.net/attachmen...ine=1336668664

my exhaust doesn't exit too far in front of the end of the bumper, but still keeps the diffuser shelf fully intact.

https://www.miataturbo.net/attachmen...ine=1336668664

you can see the turndown for the exhaust right under the bumper below the left edge of the corner lens.

some more picture to show where it's mounted...

2x4 placed flat on the frame rails...
https://www.miataturbo.net/attachmen...ine=1336669363

The gap at the diffuser ( a little over an inch higher then the bottom of the frame rails.
https://www.miataturbo.net/attachmen...ine=1336669363


Fairly level picture from the back of the car.
https://www.miataturbo.net/attachmen...ine=1336669363


Picture of the mounting bolts, 5 m6 bolts along the top, 2 m10's and 3 m6s along the leading edge. You can see the damage the diffuser has suffered thus far on the fin, some of them have been grinded down by a mm or two, not too worried at it at all.
https://www.miataturbo.net/attachmen...ine=1336669363