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Thread: Samoht's 1996 Mazda RX-7 Type RS

  1. #21
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    Sure, but flow is flow, and for all intensive porpoises 300hp of air is going to be about the same whether rotary or reciprocating. And I get that more boost on a factory rotary motor could have been a risk not worth taking, and I get that 300hp is a very reasonable (excellent!) number for that car in that era. It's certainly believable there was more on the table and Mazda had no interest in it. Whatever the case. Turbo technology really didn't start to take off til the mid to late '90s, so it's within the realm of belief that by the time Mazda could have built a single-turbo 13b that delivered the performance they wanted the FD was already EOL. Certainly, any early '90s turbo car would have been built with late '80s turbo technology, and full boost at 3000rpm was more or less the target. Delivering it at 2800rpm was sort of an accomplishment. But Saab (truly) pushed development to deliver peak torque earlier - 2200rpm c1993 - and these days turbo cars are expected to deliver peak torque at 1800rpm. In any case, if the goal is 10 or 12psi by 2800rpm with a 300hp peak, the world is your oyster. The GT3071R will deliver something like 25psi by 4000rpm on a 2.0l. The ball bearing Super60 in my old SPG did 20psi by 3200rpm (on 2.0l). I'm expecting the hybrid T3/T4 in the XR4Ti to be in that ballpark as well, having an extra .3l to help. And those are old, old turbos - ~10 year old tech. An appropriately sized twin scroll on a 13b will not have a problem, and will probably shave a few hundred rpm off the torque plateau.
    Last edited by thesameguy; November 4th, 2014 at 08:43 PM.

  2. #22
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    Update!

    I haven't really talked about the FD since the last trackday ended sub-optimally ( http://gtxforums.net/showthread.php?...-first-crash-( )

    Catchup; the car was all repaired, genuinely wouldn't know any difference to look at or drive, trackday insurance ended up covering a bit over half the cost. Previously, the engine was rebuilt by the Worthing-based specialist I was using at the time in c.2015. It was never really quite right after that, always a bit of oil smoke. In 2018 it started pressurising the cooling system, diagnosis was water seal failure, time for another rebuild. By this time I'd moved from Croydon (South London) to Cambridge, so I took it to another rotary specialist in Rayleigh, Essex.

    Anyway, they said the prior rebuild had been 'done by monkeys', water seals not properly in place, and 'had to' port it a fair bit more to get port shapes they were happy with. So running that in, then the turbos wore out, got them rebuilt, sequential turbo controller was too far gone and needed a complete replacement, oil metering pump failed and needed a (hard to find) replacement, damper blown so four new dampers. Quite a bit of money and time when the car was either away, or at home but not working 100%.

    This is what led to me buying a 350Z, initially intended to replace the RX-7. However I quickly decided I couldn't give up the FD, it's just smaller, lighter, more immediate, more urgent, more exciting. I mean, they're totally different kinds of car, for all the superficial similarities.
    However, making the RX-7 a second car was much more clearly a good thing, lower mileage means fewer expensive repairs and less of a hassle when it's offline or away for an extended period. So the 350Z was replaced with a nice practical estate car ( http://gtxforums.net/showthread.php?...C55-AMG-Estate ), and the RX-7 stayed in the garage, coming out for an occasional blast.

    The Essex specialist is a lot better than the previous place I was going; does a better job for less money, and tends to fix problems properly by getting stuff rebuilt or replaced with new parts, rather than the other place that would put in used parts... which would then fail again. After the round of repairs mentioned above, plus the odd bit of rust, it's been generally working. Even the turbos reliably hit hard with their one-two punch, followed in short order by the sound of the redline warning chime.


    Anyway, I'd not been on track since the above-linked mishap, but the latest iteration of the FD Owners Club has been bolstered by a Californian joining the ranks, moving on from RX-8 ownership. As we all well know, it takes an American to get Brits to socialise, and this year for the second time Roy organised a private club trackday at Blyton Park. I've been feeling the need to be sociable and do more car stuff, Blyton Park is only just over 2 hrs drive from Cambridge, there's not too much to hit there (it was the first trackday I did, back with the 180SX), and the car was working well - so it seemed a really strong opportunity to blow off the cobwebs.

    The trackday was good with only six cars on track at once, and with everyone going at a similar-ish pace there was none of the problems of spending the whole lap being passed or stuck behind a stubborn driver that afflict typical public days. Also Stu & JayDee, who run the Essex rotary specialists, were there which is always a nice reassurance. There were some nice cars there - one guy with a 20B who'd done much of the work himself, and a lovely Innocent Blue 2002 car with a single turbo on CE28s that was super-quick around the track.


    First session it honestly all felt like things were happening a bit quick - that's what a five year gap does I guess. But after that I got back in the swing of things, and after lunch I had a fun session chasing a slightly more modified car, going hard to keep up and trying to learn from his lines. The brakes (with CL5 pads and high-temp fluid) were solid, the car didn't miss a beat apart from the water temps running up to 108 C, so I tended not to push too hard for too long. The first corner at Blyton is a tightening radius, feeling the car pivot as you turn and brake is cool, it really likes to rotate in this situation, but controllable as long as you're paying attention. I love that it doesn't just push into understeer if you go in too fast - everything it does is in response to your inputs, it's just a matter of giving it the right inputs!

    Anyway, was a nice day out and a good way to get back into driving the FD towards the limits, as well as meeting people again for the first time in ages.

    On the offchance that others may enjoy seeing some RX-7 photos, here are some (First three pics are my car, then some of the others).













  3. #23
    Corvette Enthusiast Kchrpm's Avatar
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    Looks like a lovely, loud day
    Get that weak shit off my track

  4. #24
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    The FD is such a cool fucking car.

    I'm glad I have had the chance to drive one in anger

  5. #25
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    Ditto!

    Except I just need a chance to drive one still…

  6. #26
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    So jealous. Glad the car is back in shape and that you're enjoying it as it's meant to be enjoyed!

  7. #27
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    That looks aweome.

  8. #28
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    Still a gorgeous thing is the RX-7.

  9. #29
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    It's amazingly weird that RX-7 doesn't look dated in this day and age...

  10. #30
    The FD is one of the great drivers cars. Love the chassis, it drives lighter than its 90s Turbo Japanese contemporaries. Glad you got to give yours some proper driving again, better than ever!

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