1.8 Hybrid T28 @ 15psi
 

After spending the winter months here in England swapping out my JRSC M45 for a turbo setup I finally collected the car Friday evening after having the ecu fitted and mapped, and the sump drilled and taped for the oil drain, something I was too keen on doing myself on my driveway.

The setup consists of stock '94 bottom end with 74000 miles on, unknown head work by previous owner, FM manifold, outlet and down pipe, Turbo Technics S186 hybrid Garrett T28, cat delete pipe, HKS Super Dragger all 2.5", Walbro fuel pump, Subaru 550cc Pink injectors, DIY over the rad IC, NGK BKR7E plugs, Magnecor 8mm leads, Exedy HD clutch, Emerald K3 ecu which has 3 separate maps switchable from the dash, standard 5 speed transmission and 4.3 diff, mapped on 97RON fuel.

Unfortunately I forgot to grab the at the wheel and AFR graphs before heading home I'll ask for them to be mailed to me next week, neither do I have much information about the turbo other than it's a journal bearing core with a 360* thrust bearing and different exhaust/compressor wheels, Turbo Technics are reluctant to issue full specs for obvious reasons, I chose this over a 2560 mainly as it was cheaper and the rebuild costs of the BB cores is ridiculous the journal cores can be rebuilt for as little as £150, after a few phone conversations about the cars use, and my goals I was suggested to try the S186 with a swap from the .84 to .64 housing and clocked as I required.


Do you think the rods are on borrowed time??
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The guy that mapped the car has a fair amount of experience with Miata's, currently building a 400hp car for another customer he also does alot of work mapping big power GTR's and historic turbo F1 cars so I trust his judgment, he was amazed how well the engine was reacting to mapping and told me the timing and AFR's are fairly conservative and there was more if I wanted, although for the sake of the bottom end it was probably enough.

Did you install an Emerald ECU if my memory serves me right?

Yeah it's a Emerald K3.

I was in on your GB for a MSII but pulled out as the tuner was happier with the Emerald and it was available there and then, but due to a month long honeymoon and life in general getting in the way I've only just finished the build.

I remembered as much, I just failed to read through your post. Excellent results.

Awesome numbers! More details about turbo please!

Very impressive at 15psi !

Nice power!

Yes, I think the rods are on borrowed time.

that's one big T28. does it spool that slow on the street? Looks more like 71mm wheel as opposed to anything with a 60mm T28 wheel.

Could the ramp rate be effecting it?

FWIW, IIRC, when the DD dyno displays flywheel numbers, it's correcting the output higher to give "dynojet" numbers.

Is this on an engine Dyno????

If not, how does the Chassis Dyno determine "flywheel power"

Either way, AMAZING numbers!

Like I said, I think when you put the DD on "shootout" mode, it converts the numbers to match a Dynojet and shows it as flywheel. Something like that.

reading fail.... thanks!

I'll try again to get the full spec from TT but I don't hold much hope of getting them.

On the road it spools a couple of hundred RPM soon than the printout shows, it really doesn't feel that laggy to me, I'm sure I've seen 2560's that spool in a very similar way anyone got plot showing there 2560 results to compare?

I think I'm going to get the boost target on the high boost map reduced to 13psi and aim for 280'ish bhp until I can afford to buy some forged rods/pistons, but it's nice to know the blower has got the ability to make some serious power once I've got a good solid bottom end.

My T3 spools better than that on my 1.6L... but your power output makes me think that turbo is much bigger than just a T28.

Most 2560s on a 1.8L will make 15psi by 3500RPM easy.

Hey awesome numbers. We are running basically the same amount of boost, same manifold & downpipe, test pipe, and a 2.5" exhaust. Your turbo must be really close to the specs on mine, because my crank HP would probably be 280-290ish.

Awesome job!

Looks like closer to a 2871 journal bearing.... or maybe a 2876.

seems like everyones talking about how big your turbo is :giggle:.
Stock rods will hold up to about 250tq so you are a bit past the point where most people start to worry.

It didn't end well :(
Posted by Buck65 on mx5nutz.com in April 2011: "Well I knew I was pushing my luck with the std rods at 310bhp/278ft-lbs and even though I'd turned the boost down from 15psi to 12psi which was still making 280bhp/255ft-lbs and after 600 miles in which I've been giving it some abuse my number 4 con rod through in the towel this afternoon and parted company with the rest of the internals and out the side of the block "


In for updates from the man himself if he's reading...

IIRC he's in the process of building his engine.

As Owen has already pointed out it only lasted 600 miles before it died... but she lives on, I've subsequently had a new block rebuild with forged rods, pistons, ACL mains and four new valves with suitable grinds after the wayward piston bend all four. After the running in was completed it went back for mapping where it destroyed the clutch due to a rather aggressive torque curve, the replacement was fitted and bedded in it was mapped to a more trans friendly level for the sake of the gearbox and diff.
https://www.miataturbo.net/attachmen...ine=1322481338

Good news :D Bet that's tricky to put down on nearly freezing roads! Any chance of vids or photos?