docbong85

Need some input on deleting my air pump.
Im rebuilding/restoring an 88 GTU for my friend. Car has sat 10 years with a rebuilt stock NA with 21,000km on it. Have it running for testing/driving purposes while i rebuild a custom built motor which was pulled from previous car (this motor has sat for 13 year-ish with less than 1500Kms on it)
keg was built by rx7specialties, and after tearing it down and specing everything, i discovered they built it with two Rear S5 turbo housings. Now if im correct, only difference in front and rear housings is a port connected to air pump system, and neither one of us can fully remember if first car had air pump or not after REC built the setup. ( assuming probably not)
To further explain, exhaust system has been done with cats removed up to stock header, and ill be installing a racing beat header to finish system.
So at this point, the air pump on the stock motor is doing next to nothing. I'll also be deleting egr system, as there is no testing in our area.
Therefore, due to exhaust setup, having two rear turbo housings, deletion of egr system I'll be removing air pump.
My questions are this:
1. How to belt it?
-Does the FD idler pulley setup fit FC front cover?
-Options for two belt pulleys? Car will be street driven, so i dont want to install under-driven two belt pulleys.
2. Can stock ECU handle what well be doing to the o2 sensor?
- How necessary is something like a PowerFC (definitely part of plan down the road, but for now can stock ECU manage without running rich?)
* setup built by REC used stock ECU, dont know if it was flashed or not

j9fd3s

iTrader: (3)

if you want to run 2 belts, the Racing Beat alternator pulley is good.

the stock ecu will run ok, but it'll be really rich at idle because it doesn't have the air pump air.

plan B you can just drill the passage in the rotor housing, and then the air injection will work

docbong85

My concern is they're all undriven pulleys. This is great for high rpm to reduce cavitation, but this car will be city driven, in alot of stop and go conditions. If I'm understanding it correctly, these pulley arrangements aren't suggested for this kind of use.
I'm also installing an aftermarket stereo, which will likely draw about 1000w-1500w RMS playing heavy metal.
so I guess then next question would be, what alternator upgrade is suggested to compensate?

j9fd3s

iTrader: (3)

if you're going to do that, the FD alternator is 100A and runs a 6PK belt setup, and then all you need is an FD main pulley and a Cosmo 13B water pump pulley, or ones of the kits, Atkins has one, KSP, etc

Nosferatu

cosmo main and water pump pulley is a 5 rib belt... .guess you just run the thinner belt with the fd pulley.

j9fd3s

iTrader: (3)

i could be mistaken about the FD belt too, pretty sure its the same. i did have that mocked up on my car (FC water pump hits FD fuel rail)

Nosferatu

I think you are correct as the FD alt. pulley I have is 6rib..I haven't tried it but can't see why it wouldn't work mixing and matching with just using the thinner belt. atkins has a nice serpentine kit ..pretty sure that is 6rib also..I guess with all the add on pullies on the cosmo as the airpump is a 3rib serpentine plus 2 v-belts for p.s. and A/C..Mazda went with a 5-rib.