Turbo selection for NA8

omx500 · Postby **omx500** » Sat Jan 31, 2015 12:53 pm

Hi all. This is my first post so please be gentle! My name is Omar and I have a Nov 1996 NA8 which I bought as a stocker from its original owner down here in Hobart some 6 years ago now. I was always going to up the power in it as, frankly, I was used to a bit more. I drove a NA6 with GReddy kit and it was good, but not really enough. Development potential also seemed limited. I drove an NA8 with some sort of TO3 / FMIC etc and it was crazy, but the way the power came on and the lag meant you (or maybe I) could not exploit the handling potential of being able to drive an MX5 right on the edge, which was what attracted me to the car in the first place. So I went for a supercharged setup and currently run a FFS MP62 kit on my standard BP engine which has been fine for autocross, hill climbs and circuit sprints etc. However, I now find myself in a situation where I need to drive the car more regularly and the tune I run relies on E85 to prevent bad things happening and it is kind of inconvenient given that there is only one service station in Tas with pump E85. I could back off the boost pressure, but I don't want to. My thinking now is that I should swap to running one of these great new turbos which seem to have much less lag and better response curves instead, and use a fuel sensor to adjust tune (boost pressure, fuel, timing) depending on what fuel I put into the tank. My engine needs a freshen up anyway and I have some rods and pistons which should give around 9:1 compression. I want a turbo which will let me produce at least 150RWKW on ULP and pushing 200 on E85. I was hoping kind persons with recent experience could recommend an appropriate turbo. I hope this wasn't too long.
With thanks, Omar (OMX500)

Postby **NitroDann** » Sat Jan 31, 2015 2:57 pm

If you go flex fuel also use it to control boost.

Id go 10 or 10.5:1 for certain. The cheap basic setup would be a log manifold, 2.5 or 3" exhaust (definately recommend 3") ID1000 or 725 or whatever, and you will make around 230rwkw on E85, with a limit of probably around 180 on straight 98, but with very very good response and off boost performance (it will only be off boost at 2500 or below).

Dann

speed · Postby **speed** » Sun Feb 01, 2015 9:53 am

Welcome Omar!
NitroDann is the man. All his advice is based on facts and experience. Good luck

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omx500 · Postby **omx500** » Sun Feb 01, 2015 2:01 pm

Thanks for the welcome speed and thanks NitroDann for taking the time to reply. My choice of 9:1 probably is giving away my age and to some extent my lack of touch...I started playing with turbo cars in the 80's. I have taken your recommendation for 10-10.5:1 to heart and will make some changes. I read elsewhere that you are currently tuning a turbo'd version at running 11.2:1 so that is obviously coming from considerable experience. I'm still floundering a bit with turbo selection - I'm not even really sure how critical it is. Will keep researching here and on the other forums to see what people are running.
Cheers, Omar

jp928 · Postby **jp928** » Mon Mar 09, 2015 1:04 pm

AVO Garrett turbo, stock NA8 engine, 2.5" exhaust throughout, ~8psi boost, 162KW at the wheels,238Nm , but flat torque curve from 3k. Microtech piggy back ECU. It in a 750kg clubbie.
jp 92 NA6

speed · Postby **speed** » Mon Mar 09, 2015 1:07 pm

jp928 wrote:AVO Garrett turbo, stock NA8 engine, 2.5" exhaust throughout, ~8psi boost, 162KW at the wheels,238Nm , but flat torque curve from 3k. Microtech piggy back ECU. It in a 750kg clubbie.
jp 92 NA6

750kg that sounds like heaps of fun

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Postby **NitroDann** » Mon Mar 09, 2015 1:35 pm

162 rwkw on 8psi! And 2.5" exhaust?

GT30? Methanol?

The American · Postby **The American** » Mon Mar 09, 2015 9:41 pm

There are loads of threads on this around the place. Garrett 2560 and 2860 are common, with occasional 2871.

Mine is a 2860 (AVO kit) producing about 160kw on pulp and 12psi.

Mr nanotech · Postby **Mr nanotech** » Mon Mar 09, 2015 11:12 pm

NitroDann wrote:162 rwkw on 8psi! And 2.5" exhaust?

GT30? Methanol?

My thoughts exactly. Either huge turbo or massively optimistic dyno.

jp928 · Postby **jp928** » Sat Mar 21, 2015 4:32 pm

The dyno is at Maztech, and Anthony there does lots of rotary hotting, claiming 1000hp out of a 13b, with LOTS of work on it. Any dyno can be optimistic I guess.
The basic turbo kit is out of AVO (Berwick), so its a Garrett GT2?? The donor car was a 96 NA8 with 90k kms on it, nothing done to it.
Our dyno traces show 7.8psi peak pressure, starting around 3k, and held down by the wastegate all the way to 7200. No signs of lag - when you ask for power it comes in and stays there. The torque curve follows the boost curve pretty well also. The FMIC is pretty big (tailor made, and HEAVY!). The inlet air pipe is 2.25" from AFM to compressor, all the rest is 2.5". All the exhaust is 2.5" from the dump, right angle out the side, another right angle into a 2.5" in/out muffler 24" long , 2.5" outlet bend - thats it, no more restrictions. I think we are getting good figures because of the low restrictions on the outlet side of the turbo - I think it would be difficult to fit a 2.5" system into an MX5 without a lot of bends and restrictions... but I may be wrong. All the air pipework is straight steel tube or off the shelf silicon bends.

Its running on stock 98 fuel.
The American above is showing similar figures, but at a few psi more... dont think our numbers are unreasonable. Mate has a 94 NA8 with a Rotrex giving psi, only get 138kw at the wheels. Power to drive the blower has to come from somewhere.
jp Almac

jp928 · Postby **jp928** » Sat Mar 21, 2015 5:07 pm

oops. Mate with rotrex is showing 10psi.

jp

Postby **NitroDann** » Sat Mar 21, 2015 5:12 pm

3" without a lot of bends is easy.

Your numbers are very optimistic.

AVO kit comes with GT2560. So yeah that's a T25. And the stock avo dump sucks. I'm sure its a hoot to drive but the numbers are optimistic.

Dann

Magpie · Postby **Magpie** » Sat Mar 21, 2015 8:56 pm

To be confirmed in a week or so but a Mazda BP engine producing around 150RWKW Naturally Aspirated on E85. Throw a turbo of your choice onto this motor

omx500 · Postby **omx500** » Sun May 31, 2015 11:45 pm

Now Hobart's one local E85 outlet has swapped the pump for regular unleaded :cry:

Had to go home to pick up my laptop, drive to another petrol station on fumes, fill up on 98, then make up a new tune on the spot and drive home. Only stalled once so must have got it reasonable. Still not cool though. Must accelerate my turbo conversion. Gave it a bit of a squirt late in the drive and was surprised that it didn't ping its head off. Was noticeably less urgent than on E85 though.

Omar