NC with Cosworth making only 150 hp????

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fredmuggs
Posts: 41
Joined: Sun Mar 13, 2011 6:40 pm
Location: Sheldon SC

Re: NC with Cosworth making only 150 hp????

Post by fredmuggs »

[/quote]

Here's Jay's member info:
http://forum.miata.net/vb/member.php?u=25738[/quote]

Hey!!!
I jst sent Jay an email via the Miata.net forum. Will let you know.
Thanks,
Fred[/quote]


I talked for some time with Jay. He was interested and very helpful. Thanks for the lead.
Fred
fredmuggs
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Location: Sheldon SC

Re: NC with Cosworth making only 150 hp????

Post by fredmuggs »

Hi, All:

Got a new exhaust manifold with attendant CAT -- No change. Pulled the vacuum line from the bypass valve, per Cosworth instructions, no change.

IT IS NOT:

the bypass valve
blocked exhaust
blocked intake path
the plugs
the tune

Anyone got other ideas -- just before I pull the blower? All contributions gratefully accepted.

Thanks,
Fred
fredmuggs
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Location: Sheldon SC

Re: NC with Cosworth making only 150 hp????

Post by fredmuggs »

Brian wrote:Indeed, bypass or some other mechanic source or leak is resulting in the air not reaching the cylinders.....it's the only reasonable explanation. Bypass is the most likely source.

Either that or the converter is stuffed/melted resulting in no flow...I think you mentioned a joy ride in the car BEFORE doing the tune? It would not take much of a joy ride without the tune being loaded to melt down the cat (except this should result in really HIGH boost readings and since you are not getting that, I am back to my first sentence above as the logical source).
Hi, Brian:

New exhaust manifold courtesy of warranty. No change.

So, it doesn't seem to be:
blocked exhaust
blocked intake path
the tune
the bypass valve

Any other ideas -------------- just before I reinstall?

Thanks,
Fred
Brian
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Re: NC with Cosworth making only 150 hp????

Post by Brian »

So, the converter was melted down and blocked.....but replacement did not change your results?
Brian Goodwin
Good-Win Racing
www.good-win-racing.com
fredmuggs
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Location: Sheldon SC

Re: NC with Cosworth making only 150 hp????

Post by fredmuggs »

Hi, Brian:

Not precisely -- the shop in Charleston pulled the exhaust pipe and observed the cat element was cracked. The cracked element, in absence of any external impact damage, was sufficient for Mazda to replace the manifold under warranty. After trailering the car to a dealer, waiting a week, then trailering home and reflashing to make absolutely sure I had one of Moto Mike's tunes on board (not the factory tune courtesy of the dealer), I ran the car today and found no difference. There's no difference in noise level or response. It still makes no low end and runs out of stuff around 80 to 90 mph. I could do another $75 dyno pull to "prove" there's no difference -- but, trust me, there's no improvement. It wasn't the cat.

Neeeext?

All kinds of things going through my mind. Are the cams different in the AT motor? If I were leaking at the intake manifold/head attachment, wouldn't I see some symptoms at part throttle? Would the thing even idle? If the trans control were telling the ECU to back off, would the logs show it? Is there really and Easter Bunny?

You got any specs on the internals of the AT vs MT motors?

Thanks,
Fred
elloco54
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Re: NC with Cosworth making only 150 hp????

Post by elloco54 »

An auto trans torque converter actually multiplies crankshaft torque until lockup,don't think the trans is the problem. But if your front converter was cracked and broken pieces from that could be restricting your second converter. When you are 100% sure there is no restriction in the exhaust and the problem still exist then it's time to start digging into the supercharger
91 IMPULSE RS
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Re: NC with Cosworth making only 150 hp????

Post by 91 IMPULSE RS »

Just for the hell of it, why dont you contact Joe from Dyntronics and explain to him your problem and maybe you can work out something with him where he could possibly send you a loner ecu with one of his tunes to try out. Just to be absolutely sure that it isnt the tune you currently have, compare it to another tuners. You've pretty much ruled out any of the possible mechanical reasons. Just my 2 cents.
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Re: NC with Cosworth making only 150 hp????

Post by Brian »

I don't think the trans and tune are the issue. Something basic here...
Brian Goodwin
Good-Win Racing
www.good-win-racing.com
nc4me
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Re: NC with Cosworth making only 150 hp????

Post by nc4me »

fredmuggs wrote:Background: This NC and was purchased used. It is an auto trans car. Stock performance was as expected: somewhat higher acceleration and stronger midrange than my stock 67k miles '99 NB and very considerably stronger than my girlfriend's 103k miles NA. I soloed and tracked the NC. It was responsive and seemed to have plenty of power. I did not dyno it before making changes.

In September 2011, I installed a Cosworth supercharger kit and AEM water/meth injection kit at 37k miles. There were no important problems during the install, just some minor fit issues.

After the install, the car fired right up, still on the original tune. It idled fine and "blipped" just like it did before the install. I took it out for 12 to 15 miles at slow speeds, without kicking in the boost. There were no apparent problems. The car seemed just as before except intake noise was noticeably "hissy." During this first outing, I went once to around three quarter throttle from a roll in second gear to make sure the supercharger actually made some boost. Whoa!!! Rocket car!!! INSTANT SPARK KNOCK!!! Stop that instantly! Go home. Start the tune process. Very happy and expectant.

I contacted calibrator who provides a tune with the kit and received the first tune via email. Installed the tune (with minor software hassles thanks to Windows Vista).

With the first tune, another new car! But this one wouldn't pull the hat off your head. Very, very conservative. No spark knock, but I was back to stock (or less) performance, even though an Autometer mechanical boost gauge showed it making 8 lbs.

I data logged the car (with another $500 gadget), sent in the log and promptly received a second tune. Loaded the tune. No noticeable change.

I took the car to a dyno. It dynoed 153 HP on the first pull, when cool, 142 on the second. Stock NC's do that. Must be the dyno.

I took the car to a second dyno. It dynoed 142 then 140 HP with the dyno sensing 10 lbs. of boost.

The tracing of ALL DYNO PULLS ON BOTH MACHINES showed high variability within the horsepower and torque curves. In other words, the overall shape of the HP curve was about what you'd expect: rising steadily until a peak near 6.3 k RPM with a gradual drop off beginning thereafter. But, within that nice, smooth HP curve, the individual data points were highly variable around the central trend.

I talked to both calibrators, the guy who actually wrote the tunes and the guy who ran the second dyno. Both suggested the boost might be "blowing out the spark" under load. They suggested I switch to a colder plug with an smaller gap.

I installed fresh NGKs gapped at 30 thousandths. When I took the car back to the second dyno, it pulled 151 HP, then 139 HP on the fresh NGK plugs. Cut off the water injection, same numbers (Water alone apparently does nothing.). The same variability in the HP and torque curves is apparent. The curves MAY be a little smoother.

The original calibrator sent me another tune with 4 degrees of spark added. I've loaded that. Haven't yet made another $75 dyno pull to see the results. But seat of the pants tells me nothing is changed.

The car drives fine. On back-to-back 2-18/19-2012 track days (with 450 lbs of driver and coach aboard), I ran the car hard all day in 20-25 minute sessions without incident: no knock, no overheating. It pulls smoothly in midrange and runs out of stuff around 100 mph -- just like before. $6,500 later, my over all impression is still that midrange is somewhat improved over the bone stock used car I bought and the supercharger sounds cool when you stand on it from 3k RPM up. But it makes about the same HP as an NC with a cold air kit and muffler.

Constructive ideas, anyone?

Thanks
Maybe a shot in the dark here, but my friend with a turbo car (not an mx-5) had the same issue. Your first post on this issue is in february. Assuming you did this install in the winter and it was cold (a lot of assumptions), you could have a valve train issue. My friend could never wait to hit the gas even in the winter. He would fire up the car and floor it as soon as he turned out of his neighborhood. The only thing is that since the engine was not up to temp the valve springs were cold and he damaged them without somehow causing a catastrophic engine failure. He would build boost measured at the manifold and his boost gauge, but the boost was getting blown through the exhaust since his valves were staying open. It might be happening to your car. You would get a torque boost down low and then the power would drop off dramatically and since your motor is turning the supercharger the car would even pull weaker to redline then stock. I would do a compression test and leak down test to see if you might have messed something up. My friend only messed the number 8 cylinder on his car and it caused a complete loss of power. Good luck. My friend swapped to stiffer valve springs, titanium retainers, and swapped all valves and pushrods (just to be safe), and the car ran fine afterward (same tune).
2008 Galaxy Grey Miata Sport 5 speed: TDR2 Turbo Kit, Goodwin Racing Q exhaust, H&R front and rear sway bars, Tein Flex coilovers, Stock LSD added, and 17X9 Enkei RPF1's with 245/40/17 Dunlop Direzza Sport Z1 Star Specs
fredmuggs
Posts: 41
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Location: Sheldon SC

Re: NC with Cosworth making only 150 hp????

Post by fredmuggs »

Hi, nc4me:

I'm am still fooling around with the problem. I think a couple of my recent posts went off into space and don't show up in the forum. So, here's an update.

A couple of weeks ago (time flies when your chasing gremlins) I had a shop in Charleston run a compression test. All four holes were 215 - 220 lbs. I didn't know about such valve train problem possibilities at the time. But, since I did not dyno the car before the SC install (stupid, cheap, never again), I just wanted to make sure I didn't have a sour motor. This is a second hand car to me, so I can't vouch for how it was treated before I got it or who did what to it. Anything is possible. But, the car displays no erratic symptoms anywhere, just doesn't make much HP.

The shop which did the compression test also pulled down the exhaust pipe and found the cat element in the exhaust manifold was cracked (thought I had it, then). I've now had the exhaust manifold replaced (There's like a 60 or 90k warranty on the emissions stuff on the MX5). Replacing the front cat made no difference. Next step will be to take the rear cat out of the loop for a test. You can't see that one without removing it for examination.

Right now, I'm going back to Cosworth for any other tips and trying to confirm that there is no difference between the cams in the auto trans and manual trans cars. Maybe Mazda had a "better idea" and detuned the AT cars for old folks to putter around in.

Thanks very much for your comment. Believe me, all contributions are gratefully accepted.
Fred.
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