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MX5 tuning
marcjagman - 14/1/11 at 08:52 PM

As ECU's are black magic to me I was hoping someone here would help. I have an early MX5 engine and gearbox, believed to be 1991 1.6. I want to know how to get it chipped or an affordable after market ECU set up. I have looked on several sites and all they seem to do is give results and not the bits that were actually used. I will having the head gas flowed, which will help, getr I have no idea when it come to ECU's on how/where to have them chipped or where to get a better alternative. All help welcomed.


Bob C - 14/1/11 at 09:49 PM

You won't get any more power by "chipping" the mx5 - it's a normally aspirated petrol engine with fixed valve timing, best you could hope to achieve is improvement in mpg. Chipping can give you gains on turbo engines.
For more performance, forced induction, nitrous or a bigger engine transplant are the only real ways forward ;^)


marcjagman - 14/1/11 at 09:57 PM

Okay, so for arguements sake lets say I have a turbo with all the bits, pipes, tubing, BOV etc and I fit it to the car would I need another ECU or would I need to get the old one chipped/remapped? I have read on other MX5 sites that the standard engine can take 12-15 psi boost but I have no idea if the ECU would need altering.


snapper - 14/1/11 at 09:58 PM

Flowing the head will help as engine tuning starts with gas flow, optimising fuel and spark is what you want to do and original ECU's are notoriously hard to break into.
The real option is an after Market ECU that you have set up on a rolling road, there is realy no easy bolt on option.
Even if you could "Chip" the ECU, the new fuel and spark map means nothing if you don't measure and optimise the settings.
There is no such thing as a free lunch.


BigLee - 14/1/11 at 10:04 PM

"Bipes ACU" is what you need. You could run 6psi without one. 9psi with one, and thats if you upgrade to the 1800cc's injectors. Anymore and you'll need 460cc injectors from an RX7 or Supra, plus rising rate fuel pump etc.
A bipes is about £170 landed from the US. Plug and play. 9psi plus a small intercooler should see around 200bhp.

Lee


Bob C - 14/1/11 at 10:05 PM

The ECU in a 1991 mx5 is really old fashioned... From memory folk boosted to about 6psi & kept the stock ECU by messing with some of the signals, but for the high boost mods they always had to get a proper aftermarket ECU - I guess these days you could use a meagsquirt/spark. Yes some folk boosted the early 1.6 to 15psi & got good reliability and mpg - usually by using an FM2 kit from the states (flyin miata) & paying a lot of dosh.
Sticking on kit you happen to have around is fairly unlikely to end happily..... ;^)


marcjagman - 14/1/11 at 10:21 PM

quote:
Originally posted by BigLee
"Bipes ACU" is what you need. You could run 6psi without one. 9psi with one, and thats if you upgrade to the 1800cc's injectors. Anymore and you'll need 460cc injectors from an RX7 or Supra, plus rising rate fuel pump etc.
A bipes is about £170 landed from the US. Plug and play. 9psi plus a small intercooler should see around 200bhp.

Lee

Now that's within my price range, different injectors were mentioned but I'm sure they were 360cc, will check that to be sure, thanks. Do I google "bipes ACU" to find a supplier?


BigLee - 14/1/11 at 10:30 PM

quote:
Originally posted by marcjagman
quote:
Originally posted by BigLee
"Bipes ACU" is what you need. You could run 6psi without one. 9psi with one, and thats if you upgrade to the 1800cc's injectors. Anymore and you'll need 460cc injectors from an RX7 or Supra, plus rising rate fuel pump etc.
A bipes is about £170 landed from the US. Plug and play. 9psi plus a small intercooler should see around 200bhp.

Lee

Now that's within my price range, different injectors were mentioned but I'm sure they were 360cc, will check that to be sure, thanks. Do I google "bipes ACU" to find a supplier?


I just got some injectors off ebay from a 1.8 for £25. You'll pay £100+ for any bigger and without high pressure fuel pumps and regulators, your wasting your money.
http://www.stageonetuning.com/bipesacu90-97.aspx
This will stop you blowing the bugger up!!


marcjagman - 14/1/11 at 11:16 PM

Thanks for the info chaps


indykid - 15/1/11 at 01:53 AM

an e-manage blue would probably be a better bet than the bipes and for about £100 used, but if you want real power, you might as well go for the megasquirt PnP or the DIY PnP

tuning NA, the biggest limitation is the low compression ratio. you can skim the crap out of the head (50thou is about maximum) but you'll probably find you run into problems with head gasket failures unless you buy something exotic. our 5 gained a lot of torque with the head skim but killed the gasket in about 1000 miles.

the greddy fudge for FI is an AFPR (raises fuel pressure as the inlet manifold sees boost) and retarding the base timing but you sacrifice off boost performance for it.


snapper - 15/1/11 at 06:26 AM

If head gaskets are a problem then a Cometic would work in two ways, as long as the block and the head are true flat , the Cometic will seal it.
Cometic also do a range of thicknes allowing you to increase (or reduce) compression as required.
These gaskets are around £120