Good morning to you all.

Im voicing my plans and thoughts, had a few questions / queries and was looking for opinions.....

I’m starting my build this month (the weather is starting to warm up in the UK now)Heres my goal – The car will be used on weekend, going to events / shows etc, not for dd. I would love to get to 250whp, 2 rotor, na….. I know that some major engine work is required, if it is even at all possible? Turbo is not an option, relativly speaking mpg doesnt concearn me (highway mpg of 15-20 would do). Pockets are deep...ish.

Hers the plan:
2006 Mazda RX8 Shell.
13b-MSP 6port engine
Fresh rebuild
Porting – If I could achieve my goal with a full bridgeport then perfect. But If not the PP would be the way to go? Would a pp on the intake only be enough? Dut the the MSP having quite restrictive exhaust ports?
Racingbeat MSP intake manifold adapter plate
13b 6 port S4/5 EFI Hardware lower intake manifold
EFI Hardware ITB Kit (2 x ITB 50mm ID)
Megasquirt 2 - V3 PCB full standalone (totally removing the facotory wiring harness, both engine and chassis).Running D585R Coil upgrade in COP configuration on the Megasquirt
Injectors – I will be running stage injection, primaries to fire during idel and partial throttle, the at WOT the secondaries will kick in and overlap. I’m not 100% sure on injectors sizes needed for this build yet? Im thinking 2 x 600cc primaries and 2 x 1000cc secondaries, this should give me plenty of flow.
A larger fuel pump – I look into flow calculations on this soon.
Exhaust – Full custom exhaust – Piping diameter is to be decided.

Ok so thats the rough build outline, to summerise, heres the questions id appreciate some input on
1) Porting – Full Bridgeport? PP intake? Or simply no porting on the planet could get an na MSP engine to 250whp? If the exhaust ports are what is holding this back, then it would be cheaper to get some housings with exhaust ports already in them?
2) Injector sizing

Thanks for reading.

 

I've looked into this in the past and there are some really good material out there. Here's what I've found to give you a basic idea of what to expect.
https://www.rx8club.com/series-i-maj...-dynos-133479/

 

 

I read your thread yesterday! quite informative thanks.

The 13b rew engines in the UK aren't cheap, but the high power MSP engines can be had for around Ł350-Ł400 (it would of course need a rebuild etc) which was why I started with the MSP option.

However, factoring in the cost of labour and machine work, it may be more cost efficient to get the REW block as it would then have the exhaust ports on the rotor housing, a better starting point me thinks?

Thanks for your reply.

 

Thanks for the link, I'm guessing those power figures are at the flywheel, judging by the hand drawn line on the attachments.

In which case I'm a little way off the power goals I had in mind.

I get the feeling that even with all this extensive work to the MSP engine on the intake side of things, the exhaust ports will be whats stopping me getting that 250whp figure.

Thanks.

 

 

Utilize a standard 13b block from an FC. I'm running a 13b PP with 48mm ITB's, 2x ID1000 cc injectors, s5 internals, modified rx8 e-shaft and stationary bearings. I'm still sorting out the tune on the car and my exhaust isn't perfect for a PP, but I should be able to net around the 250whp or more number. For inspiration, check out the Green Bros NZ website. They build a ton of PP drag cars that range from 250whp to 320whp. Also, drivability isn't nearly as terrible as everyone claims with a proper tune.