totally new to mx5’s and to your forum…
i want to build the best most fun mx5 ever carrying on the original ideals of the mx5 design. so engine wise i want to do what everyone says not to do… try increase power on a buget with out forced induction. so heres what id do:)
keep the bp-ze in there
.skim head 0.50
.put a cut down exhaust cam in place of the intake cam
.possibly go for motorbike itb
.custom ecu
.slightly higher rev limit
should see 150bhp?
if i was to use a bp4w head on the bp-ze block would that have any advantages to make it worth doing?
i would be trying to do all the above over time nearly all d.i.y for 1500£
i currently own a opel manta with a c20xe redtop 2.0L engine i fitted a set of bike carbs all set up right to the totally standard engine and have dyno from before and after an can definately feel a good gain ( 10 bhp) not just extra noise like people claim u get from fitting carbs/itb to most engines…
other options are more complex like trying to fit a 4age 20v? or zetec i think my modding the orginal engine would suit me best … so what id like iss for everyone to pick faults in what i plan before i do it all wrong:P , do you think my estimates are realistic? could i do it better for cheaper? i know the itb wont add much bhp but i belive they will add abit and i love response and sound !
Just replace the engine with vvt 1.8 from a 2001-2005 MX5. That’s already 150-160hp. Far cheaper.
i think id over looked that option for 3 reasons …
1.the hole wiring of the vvt into my na? i have got a friend who would help me do a mega squirt but when i have tried to fit engines in the past modifying original ecu to work i have often never got the engines running right…
so what can be fitting ? gearbox ?
ecu wise should i go mega squirt 3 for the vvt or standard na8 ecu+ a device to control vvt or should i go full 2001-2005 ecu?
i have had a look on Google but stuggling to find a good link to the info i need
2. the mods i suggested are head off only so if i have to mod anything or make changes to the work ive done its just the head to take out , no worrying about swapping a engine out as with other projects there is always slight things wrong when i fit clutches back to newer enginnes ect? just might save me a head ache or too.
- i can keep my engine and get a second head get it skimmed and exhaust cam for next to nothing? head skim 150£? exhuast cam 20-30£? should give it a bit more bhp 10-15? not really figure chasing anyway just want it to be bit more spirited then decide in a years time if i should go for itb or full swap out for a newer engine
people keep saying you cant get any noticeable gains for a good price on the na6 and na8 . but im sure with a head skim and cam + a exhaust u wiill get least 10-15bhp? which isnt all that far from the 140-150 range for less then 200£
i mean check this guy out he’s done well with similar ideas to me …
http://www.youtube.com/watch?v=9ye2Fn62xDc
stock 2002 bottem end & bp4w head … so i thought most the bottom ends are simular in the (bp family) there for I could use my bottom end a bp4w head shaved with cam then just add itb if i wanted and get my 140-150 or slightly more with itb which could be done with two investments 250£ for head ,shave, cam then a further 1000£ on the itb if i wanted to go that route:)
thanks for the idear on the 2001-2005 engine swap i am weighing up the work now i just want more feed back before everyone jumps to swap the engine, add a turbo , add a charger…
Just get hold of a cheap rotten Mk2.5 1.8, and transfer the whole loom etc to the Mk1; I think there is some faffing about to do with getting the popup lights to work, but thats about it. You could even just drop and transfer the front subframe etc.
The most I have heard anyone get out of a street B6 is Mazda, at about 150hp, on a prototype motor, using the MAS from the Mazda MPV and a heap load of ECU trickery. No such thing as cheap significant power on the B6/BP. When the perceived wisdom for the last 25 years is that not that much power can be wrung cheaply from the B6/BP, it usually has an element of truth. Going to the VVT engine is cheaper, considering you can get a rotted VVT MX5 for £600, that will include the 6-speed box, LSD etc. The later BP is also a more reliable engine than the earlier BP, which has a tendency to turn into an oil burner.
GRM spent a lot of time tuning a Miata engine, including headwork. The gains were marginal. Your existing engine is unlikely to be making 125hp right now (assuming you have a 93-96 1.8 on the 8 bit ECU).
Solomiata’s website is a good source for modifications, if you want to raid the Kia parts bin.