The 3071 isn't the problem here though. I agree that a .63 turbine would be much better with that turbo on a miata. However there is something wrong in his setup it's making 270whp @21psi.

OP, what is your injector duty % and what size injectors are you running? It is possible that your clutch isn't holding and it's slipping through the powerband causing low numbers. If you're duty cycle % is lower than it should be for 21psi then maybe there is something choking the engine. Dunno, I'm trying to think of any scenario here

 

I agree the 3071 is not the problem. I don't think cams are problem or solution either. Soviet made 450whp on a bone stock NB1 head.So I think there is some other issue elsewhere. I would start at looking at physical timing.

 

Agreed. Soviet was running a 6758 which is fairly comparable to a 3071 as far as power potential. I think he ran 28psi to make his 450. 3071 @24 psi should be in the 375-400whp range IMO.

 

Not by this much power at this power level. He's got a major problem he hasn't found yet.

Possibilities include, but aren't limited to, cam timing (yes I know he checked it but I don't have enough fingers and toes to count the number of times people have "checked" it and they were looking at it wrong), spark timing (we don't even have a log so we don't know if MAT retard or something else is intervening), broken ring (haven't seen a compression test), bent or burned valve (haven't seen a leakdown test), restrictive exhaust (don't have a clue what he's running), don't know where he's got the boost gauge plumbed to the system, O2 gauge may be calibrated wrong and it's running too rich or lean, AFR targets may be wrong, exhaust leak, boost leak, spark blowout, mismatched injector, or something else.

Post a log of it boosting. Post the tune. Post pictures of cam and crank timing marks aligned. Let's start there. These are the basics.

Then we can look at compression/leakdown tests if necessary and proceed from there.

And so it is clear, chassis dyno numbers in Europe ALWAYS read 15-30% higher than American dyno numbers. This is because the European standard is to take the measured wheel horsepower and add to it to guess what the engine is making before the transmission, driveshaft, differential, CV axles, wheel hub, brake drag, and tire rolling resistance are added.

 

~sigh~

The turbo absolutely can be the problem here. Notice how we haven't seen a log or dyno yet? Probably because he doesn't hit his "21psi" until 6krpm or later.. turbo power potential is moot if you aren't in the right spot on either the compressor or turbine map. The 3071 compressor is perfectly capable of producing 270hp at a PR of 2.5. That turbine probably needs 200hp+ to get going.

 

Most decent European dyno operators will give you two sets of results - WHP and FWHP. WHP should, in theory be the same as the same model dyno in the US or anywhere else in the world.

FWHP is a fudge because people like bigger numbers for bragging rights, and that's what the manufacturers use (although I'd imagine their numbers are properly measured, rather than made up...)

 

If everything on the engine is setup correctly the 3071 even with that large a/r would still be on boost way earlier than 6000rpm. Maybe OP has a boost leak and the compressor is spinning it's brains out trying to make the boost, that is a possibility.

He needs to post a log like everyone is saying

 

I am trying to get car back onto dyno, but looks like base timing when we locked it at 10 to set and the timing light we used was no good as i have tested it with 2 other lights and both show 6 deg base when supposed to be locked at 10.

Full 3 inch exchaust no cat 1 muffler at rear that i have checked has not collapsed etc etc.

Full fuel system dw300 pump fuel reg changed (boost refrenced) and bosch 1000cc injectors.

Good to see other people have made over 400whp on stock head cams.

Turbo is not laggy in my books. Would be on fullboost by 5000rpm.

 

Just called dyno operator he is saying cant set timing without a advance retard timing light like his ?
Ive only ever used a plain old connect on number one and point timing light ?

 

To set timing you lock the timing table in tuner studio then point the timing light at your crank pulley. You change the crank offset in tuner studio until your timing mark at 10 matches the commanded timing mark on tuner studio.

 

Cam timing off is my first guess. Possibly a tiny restrictive intercooler. Or very large boost leak.

 

andym i have played with it before when setting up my new 36 2 trigger wheel and all tests of timing done with it locted at 10deg in the tune.

patsmx5 intercooler is around 20 inches long by 10 inch high. Cams and crank all line up have checked them 20 times all the dots align etc etc. I am going to make one of those pvc boost leak testers that go over the front compressor housing and hook up to your air compressor to check for leaks

 

Do you have an aftermarket crank pulley damper? There were a few cases of them with timing marks in the wrong place, so may be worth checking...

 

Post pictures of your aligned cam marks

Post your tune msq

 

Dont have tune on me at home on my laptop it is.

Standard crank pulley used and i have exposed cam gears and can see the alignment on the crank spacer plate to oil pump as i have the top half of the covers, of my front of the engine all the time.

 

Great. Send pics when you can.