mx5cartalk.com

What that poll fails to reveal that of the 4/59 that had blew running bolts, no where did they mention that the cars in question were doing experiemental mods to there wastegate can and or actuator, bypass boost cut via a resistor or how much boost they were running.

I dont understand why sepo's attempt to run lots of boost via an MBC, without changes to fuel, ignition and boost electronically. They drive there cars like there stolen, complain of compressor surge, turbo blows and then put it down to a faulty turbo.

The IHI isnt the greatest of turbo's when compared to its competitors but I refuse to buy into there hysteria.

Of the first ten cars, nine were modified which raises a LOT of questions.

Would the American SEs be slightly difft to Aussie cars (difft fuels) ?

I would look locally at the history of failures to see if there is a local trend.

With the size of the turbo on the SE, to get 10psi, its spinning at a much higher RPM than was mazda originally intended for, so if they're modifying something beyond what the manufacturer has, and it breaks, what can they expect? Simply solution....buy the manifold and dump pipe off an SP, and bolt on a GT28RS

bruce wrote:Of the first ten cars, nine were modified which raises a LOT of questions.

I would look locally at the history of failures to see if there is a local trend.

The moded turbo's refer to blouche unit's that were originally offered by FM as part of there power upgrade, long before any turbo failures were reported. The re-worked IHI consisted of a 28lb/min compressor wheel and 7 degree turbine clip, ie high flowed so they can run large amounts of boost.

Eight months ago, FM stopped selling re-worked blouche units as they were failing. Blouche assert that the failures were due to oil starvation (priming?). Ironically if you talk to the local lads who track there SE's they seem to have issues with crankcase oil re-circulation which has been easily fixed, but issues with turbo's blowing in the higher boost has not been seen.

Would the American SEs be slightly difft to Aussie cars (difft fuels) ?

The american SE claims to be 178hp and does 0-100 in the low 6s. This is not the case with the local SE, whether its down to tunning/EPA would need the car here for testing.

I would add a larger intercooler with a CAI to that mix. You've got the exhaust breathing better with the downpipe, so making the inlet breath better with CAI and run cooler with a larger intercooler will see the turbo spool easier to get it to 10psi. Wouldn't have the oil flow would be a problem.

THE REAL BORIS wrote:Thanks for the replies. ChipTorque dyno'd my car standard at 107.8 rwkw. That is 145.5 rwhp & if you add transmission losses (approx. 32 hp) it's as near as damn it 178 flywheel hp.

I am not disputing your figures, but I do not believe mazdaspeed miata is identical to the MX5 SE.

Miata mazdaspeed

Power: 133 kW , 178 HP SAE @ 6,000 rpm; 166 ft lb , 225 Nm @ 4,500 rpm
Premium unleaded fuel 91, 0-60mph 6.6 sec final drive 4.10

MX5 SE

Power: 121 @ 6,000rpm, 206nm @ 4,500rpm, Premium unleaded fuel 95, 0-100 km 7.8 secs Final drive 3.636

Got any suggestions to improving the oil circulation then, if that is where things are pointing?

If your experiencing blow by upgrade the PCV valve to the FM one, the OEM mazdaspeed PCV is only rated for stock boost.

The recirculation mod applied to tracked SEs that experienced large amounts of oil loss. It basically involved just capping one of the re-circulation lines, pm boyracer its his mod.

I know Simon's old OEM turbo was farnarkled when they took it off (his setup was dead stock).

removed for an upgrade

The SE oil issue is not blow by. It is crankcase pressurisation. See, the SE has a factory fitted crankcase evacuation system using a bernuolli effect from a back cut tube in the inlet pipes to equalise the pressure between the camcover and the sump via a plumbed oil catch can that drains back to the sump. Our race cars experienced excessive pressurisation due to the higher and more consistent revs which caused the oil in the sump to be under greater pressure than the camcover and push oil back up through the sump drain, through the catch can and out into the engine bay or inlet tube.

The fix is simple, we block off the sump drain, so it can't push oil back into the catch can and starve the sump of oil. We still use the PVC valve and feed the exhaust side breather into a CAMS approved catch tank with an atmosphere vent - problem solved. After 5 races like this, I had maybe 20mls of oil in my catch tank - that, is blow by.

The guys in the states with problems, are not telling you all of the story - most of them don't even understand how a turbo works.

THE REAL BORIS wrote:I would like to know what other people are doing with the choice of after-market turbos and whether the FM dp for instance, is compatible with those changes. Checking out the prices for a new IHI for against those upgrades at the moment.

The short cast turbine outlet (SCTO) at the back of the IHI is not compatible with any garret turbo's. Therefore if you still wanted to use the FM downpipe you would have to custom make SCTO that would fit both the garret and the FM downpipe.

From a practical, efficient and cost point of view thats not feasible, it would be cheaper just to fabricate a new DP using like dual gas set up that bolts straight to the back of the turbo.

CT wrote:
The SE oil issue is not blow by. It is crankcase pressurisation. See, the SE has a factory fitted crankcase evacuation system using a bernuolli effect from a back cut tube in the inlet pipes to equalise the pressure between the camcover and the sump via a plumbed oil catch can that drains back to the sump. Our race cars experienced excessive pressurisation due to the higher and more consistent revs which caused the oil in the sump to be under greater pressure than the camcover and push oil back up through the sump drain, through the catch can and out into the engine bay or inlet tube.

The fix is simple, we block off the sump drain, so it can't push oil back into the catch can and starve the sump of oil. We still use the PVC valve and feed the exhaust side breather into a CAMS approved catch tank with an atmosphere vent - problem solved. After 5 races like this, I had maybe 20mls of oil in my catch tank - that, is blow by.

Thanks for the explanation CT. Although i didnt say blow by is the cause of the oil issue.

The mention of crankcase evacuation issue was brought up in reference to turbo failure as a possible cause, blouche asserted there units were failing from overheating due oil starvation. Similarily a few tracked mazdaspeed users were complaining of the same issue yourself and boyracer experienced although they did not address a fix. Pounding the car around the track minus 2L isnt going to be nice on the turbo let alone the motor.

The guys in the states with problems, are not telling you all of the story - most of them don't even understand how a turbo works.

Agreed.

178 HP SAE

SAE is a difference measurement standard to here.
And 91 PUMP octane premium fuel is equivalent to 95RON

rjastra2 wrote:

178 HP SAE

SAE is a difference measurement standard to here.

And 91 PUMP octane premium fuel is equivalent to 95RON

Correct

In the US, octane ratings in fuels vary between 86-87 AKI (91-92 RON AU) for regular, through 89-90 (94-95 RON AU) and 90-94 (RON 95-99 AU).

The SAE conversion factor doesnt explain why the SE doesnt produce 225nm of torque nor does it explain why it doesnt do a sub 7 second 0-100.

THE REAL BORIS wrote:
Initial cost comparison has the USA turbo at approx. $2k US (can be found as 'low' as $1,780 US). Mazda OZ want $5,500 AUD!

Perhaps Blackster will be able to point the way! especially with a budget like that.

Heh, I wish.......

$5,500 for the IHI lol, bring on FMII turbo upgrade with gray nurses still left in the pocket.

In all seriousness though, what is the life span of an OEM turbo if its manipulated and or punished? If that turbo lasts 50k I would consider that pretty good.

If there really is a turbo failure, then take the preventative step and have the IHI high flowed, it will mean the compressor wheel, turbine clip is upgraded and seals will be changed. Bonus is that upgrade will give you 180rwkw @ 15 psi if you choose to run it that way.......

Locally I got quoted about $1k which doesnt include machining. The other option is to send the unit to blouche themselves who charge $450 US to do the same job.

As our manifold doesnt support any other turbo and manipulating the flange is a dodgy practice, the only other alternative is custom. IE SP motorsport manifold or some other custom manifold, garret that supports T28 flange and have a custom downpipe made up. Around 3-3.5k for this option seems like a reasonable estimate......

I have an SP manifold + DP, running a GT28RS on my clubman, which will be transplanted onto the SE soon.
Manifold - $850
DP - $500ish (mine cost $650, but that was also with all the oil and coolant lines)
Garrett GT28RS - $1300
You're gonna be looking at around $3k fitted, but you'll also need to either modify or replace (better option) the factory piping to support the extra airflow the new turbo produces. For that matter aswel, you'll probably want a new ecu (or piggyback), as the flow characteristics of the garrett will be different to that of the standard turbo.

PS When I get around to bolting up the new bits to the SE, I'll take a photo of the two turbo's sitting next to eachother, just to show how small the SE turbo really is

Here's some I prepared earlier...