felixblack1

Is that your yellow series 2 rx7 in Zoom (27)?
If so, that was one of the best rotors I've seen in zoom!

The article never really told us your secret to fuel economy. Is it just careful tunning combined with the ability of Autronic???
I'm getting best of 15L/100km with EMS on the standard turbo. However I’m almost sitting on positive psi cruising at 100km/hr. I'm currently in the process of fitting a to4, would I be correct in assuming that I would get better fuel economy during highway driving because the to4 would be barely spinning? Or would the airflow of the to4 still be more then standard? I do except the fact that it's a turboed rotary and fuel economy shouldn't be an issue.

HWO

Peter is pretty busy, he may not answer this for a while i suggest you e-mail it to him as he check that pretty often unlike the forum

he is busy making a monster for a customer

cheers
Shane

RICE RACING

Hi felixblack1

Yeah that is my car in Zoom, thanx for the comments.

The economy is a combination of many things, I mainly put it down to a few things in particular.

Engine: 9.0:1 compression rotors, 2mm seals (different from quoted in article) ported/polished primaries and secondary ports and race exhaust ports.

Exhaust/Turbo: tunned length manifold, to4 turbo, 1.32 rear housing.

Intercooler/Intake: my own design FMIC, ported throttle body and ported intake manifold.

ECU: Autronic set for around 15:1 af ratio at cruise (1 atmosphere and below) conditions.

From the engine manifold etc perspective my engine is very volumetric efficient at most revs above 2800rpm. All of the above specs play a part in the fuel efficiency I get out of my car.

The KEY to good fuel efficiency is to let the engine breath... and then breath some more, but not at the expence of air speed ! this is critical...so long as the air speed in the ports is keep to acceptable levels to allow good fuel mixing after the injection has taken place then you are on your way to getting some decent (for a turbo rotary) fuel economy figures. Assuming you can resit the temptation to use all that extra performance potential that gets unlocked at the same time.

RICE RACING

Oh and to answer youre question better, yes you will get better cruise economy with the to4 as apposed to the stock turbo if you can drive in the same condition, becuse of less engine back pressure making it more efficient. Bit like the same increase you get in economy when you put a set of headers on a n/a car.

With the mazda turbo I too used to have that positive pressure you are talking about when travelling at speeds above 110kph and any time I went to go up hill or increse speed even slightly my boost would go to 5 or 7psi...killer for fuel consumption!

With my set up at WOT in 4th at revs below 4000 rpm it is hard to get past 11 psi boost, I know this is not everyones cup of tea, but it works good for me cause I have the power where I need it from 6000 rpm to 8500rpm.

felixblack1

I noticed u ported the exhaust ports. I'm rebuilding a series 5 motor and am getting the intake ports done. Is it worth porting my exhaust ports? I still need streetability.

1 more question:
my stationary gears are the series 5 nitrided type, stationary gear bearings are being modded for more oil flow, oil pressure increased and the rotors will be clearanced. Will the engine be capable of 8000rpm on a regular basis?


Thanks for your time!
Felix

crispeed

Yeh!
Peter been buisy with that monster for some time now. He don't have time for us poor folks any more!
Ask his HWO(Shane) how neglected he feels now!

crispeed
87TII
9.20@150mph
651RWHP/520RWTQ