Glavas

Hey guys. I've recently bought a series 4 with a series 5 engine.

Still learning manual, so i'm fairly bad, and it's a brass button clutch so it's no piece of cake. but anyhoo.

In third when i try to rev past 3k it makes a backfiring-ish noise and won't pass 3k rpm.

Temp reads normal, sitting at a nice even 90 degrees. I think it might be due to the boost the car is pumping, i think it's running 10 but stock is 7.

Anyone have any input? perhaps knows the problem?

Apart from this and the alternator belt being loose, the car's a cheap beaut!

Aleks

Aaron Cake

iTrader: (1)

The S4 to S5 swap is not straight forward. It would help to know how it was accomplished. All S4 electronics on the S5 block? Or a complete swap to the S5 electronics?

Is the car fitted with an FCD?

Does it sputter and backfire only under boost or also at low throttle?

Glavas

I believe it's all s4 electronics on s5 block. it says on the receipt "removed old motor and fitted to this block" then it has a bunch of parts replaced, nearly everything replaced and there's a trade in for the s4 blokc which would suggest this?

Overall, including s5 engine, turbo manifold + rebuild cost $5,600 AU.

I don't know what an FCD is :S

And it only backfires once it hits higher boost, up to 7ish it runs fine.

Thanks for your help,

Aleks

Glavas

It just started spluttering, i pulled over now it won't run!

The engine cranks and it splutters for a while and then nothing

Petrol was running low, but i don't think it's out.

any ideas?

Aleks

pdtaylor18

S4 loom and S5 looms are totally different so would need the right splicing at the ECU to get everything running right. I have done this myself but went the easy route and reloomed my entire car (TII cab), I say easier but i was not happy with splicing. I think we need to know exactly how the swop was accomplished, engine is straight forward as its the same but I think more information on how they have sorted the electrics would be a help. This could be anything from fuel cut, AFM to fuelling issues, the more info you can supply the better.

Glavas

Is that only for factory ECU?

I'll have to have a look, the car's at REVS atm which is the local Rotary specialist.

Also, I don't know if this is normal but my spark plugs seem to be really far into the block and impossible to take out.

I was looking at them, there's a little metal guard around the plugs themselves and i can't get a spanner round it.

Is there some special tool or is it just messed up?

But yeah, i'll find out what it is but i think it's spliced s4 loom onto an s5 block.

ECU is a microtech ls10 (?) something along those lines.

Thanks for the help thus far!

Aleks

Aaron Cake

iTrader: (1)

You need to mention things like a Microtech when asking a question. Not doing so led us all down the wrong path.

If the car has a Microtech, then it's likely none of the factory EFI wiring was used.

Your sputter may be based on poor tuning, or ignition noise.

Glavas

Sorry, my mistake, completely forgot about the ECU!

I hopefully get the car back on monday, fixed with a new tune.

Few more Q's though!

Is factory boost on the S5 13b 7psi or 9psi?

About my spark plugs, should they sit so deep?

Apart from mentioned possibilities, could this be a vaccuum leak?

How high should my FC idle? currently it's 1180rpm fluctuates between 1080 and 1280 and then stops at 1180 for a while again.

I'm being told by friends that this is too low, but none of them know **** about rotaries, but sadly neither do i...

Aleks

Aaron Cake

iTrader: (1)

Factory boost is 5.5 PSI I believe.

The spark plug holes have a bit of a hood over them. Thick sockets don't fit very well. Special spark plug sockets with thin walls are available.

Your idle is bouncing around because the car is tuned too lean at idle.

The stock car idles at 750RPM, and around 800 RPM is where it should idle as long as it's not aggressively ported.

Based upon what you said, it just sounds like the car needs to be tuned by someone with clue.

Glavas

Got a call from revs today, aparently a bad tune + over boosting = blown apex seals.

Sigh, time to save up some more moola!

Aleks

Aaron Cake

iTrader: (1)

Ouch. Sorry to hear that.

Glavas

Meh, considering the modifications the car already has, and the price I paid, i figured something like this would happen.

Rebuild time soon!

that's three cars in 1 year that i've managed to skrew up though

Magna - BHG
Soarer - Big end bearings
RX-7 - Blown engine

You guys think $4k is a good amount to budget for a rebuild + mild port?

Aleks

Aaron Cake

iTrader: (1)

You will have to post what you are getting for the $4K in order for us to judge.

RotaryMazda

If I may randomly interject for a moment.. Is there any place on the forums with detailed information on swapping an S4 engine into a S5 GTU?

Glavas

Soon as I find out I will!

It might not even happen, I might do the rebuild at work.

What is a good brand to get for the rebuild materials? Can you buy rebuild "kits"?

I don't wanna use some cheap crap.

Along with the rebuild will be an extended street port and a tune at 9psi.

That sound healthy? It's a daily.

Aleks

trochoid

iTrader: (6)

You should start your own thread for your question. Simple answer, change the front cover, MOP and everything that bolts to the bare block/keg from the S5, keep the S4 flywheel.

Download the FSMs here.

http://www.wankel.net/~krwright/cars/rx7/manuals.html

Aaron Cake

iTrader: (1)

That's a fairly large downgrade. 146 HP vs. 160 HP and 1,000 RPM less on the tach.

Unless you are referring to a TII engine.

Most of the vendors sell engine kits. Atkins comes to mind as the only supplier I know off hand. I've used their kits in the past and they are of good quality.

Alternatively, you can just buy an engine gasket set at the Mazda dealer, as well as the seals you need.

Sure.