power difference - se vs sp

JSE · Postby **JSE** » Thu Sep 28, 2006 3:22 pm

where is the power difference made?

is the sp just run on a few higher pounds of boost?

JBT · Postby **JBT** » Thu Sep 28, 2006 4:22 pm

where is the power difference made?

AFAIK: Turbo, intercooler, boost control, exhaust and ECU......doesn't leave much does it?

Garry · Postby **Garry** » Thu Sep 28, 2006 4:24 pm

They use different engines with a lower compression ratio in the SE and different valve timing as well as the things JBT mentioned. AFAIK a stock SE runs slightly more boost than a stock SP.

PT · Postby PT » Thu Sep 28, 2006 4:56 pm

That's right.

The SP runs an N/A MX-5 engine with the standard high compression, also runs a bigger turbo, intercooler, intake and exhaust.

The SE has a low compression engine for turbo reliability and is suited to running higher boost, for longer, but at low boost applications (standard) produces less power.

kitkat · Postby **kitkat** » Thu Sep 28, 2006 5:02 pm

has anyone got a dyno sheet showing the power curve of the two engines???

Calling stock SE & SP owners... post up your dyno sheets.

Postby **Okibi** » Thu Sep 28, 2006 8:35 pm

STOCK SE

STOCK SP

Alf · Postby **Alf** » Thu Sep 28, 2006 10:48 pm

Okibi wrote:STOCK SP

Sorry, Okibi, I don't think so. Probably had the $2 mod.

The SE's about the same, but at the Melbourne Dyno Day, stock SPs were running about 108 - 118 (fairly big variation). Two dollar modded ones were in the 130s though.

Cheers,
Alf

blackster · Postby **blackster** » Thu Sep 28, 2006 10:55 pm

Alf wrote:
Okibi wrote:STOCK SP

Sorry, Okibi, I don't think so. Probably had the $2 mod.

Cheers,
Alf

Tend to agree, 20-30% of power is lost through the drivetrain, so its highly unlikely that a stock SP is putting out 140rwkw.

PT · Postby PT » Thu Sep 28, 2006 11:19 pm

I don't have the chart (never got one :evil:

) but mine made 108rwkw stock.

Postby **Okibi** » Thu Sep 28, 2006 11:36 pm

Nope no $2 mod on that run.

bigdog · Postby **bigdog** » Thu Sep 28, 2006 11:46 pm

Stock SP figures vary considerably - there were obviously well tuned and poorly tuned cars coming off the 'line'. Steve's SP a the recent NSW dyno day had run 127rwkw on the same dyno at a previous day, and achieved 153rwkw with the $5.60 mod (well that's what it cost me, and mine ran 147rwkw on the same day with the mod, so our cars were very close) an 'average' figure for SP's would seem to be around the 130rwkw mark, with SE's around the 110rwkw mark - 20kw between them is about right. Spend money and time on either and more power is available... but the same goes for any car really and wallet racing has always bored me :lol:

Bottom line is quite simple - buy the one you like to drive the most. If neither are powerful enough to satisfy and you want a real HP monster for minimal bucks, follow Sean's example (and many others) - start with a low cost NA 1.6 - for less money than an SP or SE you'll have a quicker car, and possibly a more complete package if you do it right.

Postby **Okibi** » Thu Sep 28, 2006 11:47 pm

nahh thats not my SP, if it was i'd paint it baby blue and trade it in on a pair of SEs

Marty · Postby **Marty** » Fri Sep 29, 2006 8:21 am

Here are my dyno sheets before and after the mod as mentioned above by Bigdog. Can you pick which one is which?

Postby **Okibi** » Fri Sep 29, 2006 8:26 am

My bad, I just remembered that \"stock\" SP had a K&N Filter.

This one is also stock except for a K&N and shiney 17\" wheels.

Garry · Postby **Garry** » Fri Sep 29, 2006 9:48 am

A stock SE runs less boost than a stock SP. The stock SE is 7.3 psig & I thought the stock SP was just over 8?.

For some reason boost levels fluctated a lot on the SP. A stock SP will have anywhere between 6.5 and 7.5PSI. Which works out to be around a 10rwkw fluctuation. My car made 7PSI as delivered from Mazda but after the turbo was replaced the boost dropped to 6.3PSI. :shock:

0.7PSI makes a huge difference. The car felt very lethargic. A quick adjustment of the wastegate bracket fixed that.

I thought stock SE's were in the 7.5 to 8PSI range? I remember reading that the US cars produced more boost than the official figure Mazda put out at the release of the car.

but at the Melbourne Dyno Day, stock SPs were running about 108 - 118

The guy with the SP with 108kw has a sick SP, or maybe he's unfortunately aquired one of the low boost turbos like my replacement. A healthy SP with proper boost should be around 115-125kw. Though I dont remember ever seeing one make less that 120kw at our dyno days.

On a slightly different note.

Does anyone know why Mazda would have used a carbon fibre drive shaft on the SE. Does it save weight or is it to solve some NVH issue? I've heard of both theories. If it saves weight would it also reduce drive line losses?