Splinemodel

So this is part of my continuing quest to find and buy an Rx-7.

Today I looked at a Montego Blue 95 (built in Dec 95, interestingly enough), with 50,000 miles. It wasn't perfect, but most of the flaws I understood.

A couple questions:
- when bringing the car to a little above idle I heard a pair of soft pops. The noise came from the exhaust. I haven't noticed this before, but never have I test driven an FD with aftermarket exhaust. Anything screwy here? Is it a turbo blow off valve or something plain and simple, or is it detonation or something crazy like that?

- The car had a vdo boost gauge that read as high as 13psi. (It went 13-11-13), but the guy said he had made no modifications that would have effected the boost. Is the gauge to blame or is something screwy going on?

He had the car serviced at PFS not long ago, so I take there's nothing blindingly wrong, but please let me know.

Thanks

1bad7

both are perfectly normal for a car which has anything done to the exhaust. the slight pop ur hearing is just a little backfiring but that happens to every rx7, especially when downshifting at high rpms and upshifting at around 3k (this is where the secondary injectors come on so theres a little more fuel thats unburnt). the increase in boost is also normal for a modified rx7. when i only had my downpipe and catback installed i would spike to as much as 14lbs. if you do decide to get the car then try not to push it until u either get a boost controller or an upgraded ecu. hope that helps

maxpesce

the Boost pattern sounds High for just an exhaust - with my mods (see my sig) and stock ecu I generally get 11/9/11 unless its cold (>45) out and then I can get spikes to 14 and the ecu hits fuel cut on me.
The Guage may be optimistic because I think the latter ecu's hit fuel cut at 12-13psi
I have a very early car w/ build date of 2/92

and BTW the easist way to get more boost is to increase EXHAUST flow - so any improvement in the exaust system will improve boost - it will build faster and may peak higher if the boost control (primarily wastegate) can't hold it down.

Splinemodel

Thanks for the info.

Actually, the car only has an aftermarket catback. No downpipe or midpipe. I think the gauge must be off if in fact the fuel will cut off at that level.

The thought had occured to me that I may need a boost controller and a new ecu with this car. The list price is 18 and it would need some mods, which would add up considering that I probably couldn't get it for less that 15 unless I drugged him up before I made the offer.

I'm going to look at a 94 later today. I suppose I'll have questions about that, one too.

Thanks again

{edit}
If I were to get a boost controller, is the Profec A worth it? Now, I'm an EE who knows his way around fuzzy logic and neural networks, but I've seen bad implementations. Any clues there?

maxpesce

The 95 may just be worth that much - with a 12/95 build date it may be among the last 20 or so FDs brought into the US. By then the J-spec 96's should have been coming down the line for 2-3 months already - New model year production usually starts in September or October of the previous year.
Production of the 93's started in Nov 91!
and went on sale in the US in January 92 at the LA Auto Show though I think the first deliveries to the US general public were not untill March or April.
The Last US car had to be built prior to 1/1/96 and (be a 95 model) because thats when OBD-II went into effect. Though Leftover stock of 95's were sold until mid 96 with some dealers calling them 96's

1bad7

the profec-A isnt recommended since it confuses the sequential system. if you want the best boost controller for the stock twins then go with the profec-B. alot of people have it including me and it works perfectly. a good deal for $320 too.

Splinemodel

The 94 wasn't anything special, so I ended up bringing together some of my resources and going for the 95. The paper work is fluttering back and forth now. Unless something unfortunate happens, I should be able to drive this baby home on the 25th or 26th.