Later Engine Spec/ differances?

[Jovic82]

Hi ,

I have recently stripped the engine down in my rx and am now at the point where i need to start measuring and ordering up the replacement rebuild bits.

I was told by the previous owner that the car had had a 99 spec engine block fitted and all the other 92 spec ancillaries (turbos etc) were original.

Is there anyway that i can tell if this is true now that i have the engine block apart? any differences on the housings / plates / rotors etC?


Cheers
Nick

[HaywardRotary]

There is no difference between engine block parts that is of any major significance.
All earlier parts fit internals of engine block.
Regards
Carl

[rei99]

Hayward, in your opinion the later specs engine with all accessory (intercooler, turbos...) is more realible than early?

[HaywardRotary]

They are the same really,only advantage of newer engine from reliabilty point of view is newer solenoids and wiring loom.
Regards
Carl

[SiH]

Carl - do you know what the turbo differences are? No-one seems to be able to provide me witha decent answer. I know that the seals are different, but some say they flow more, others say the internals are otherwise the same.

The reason is that my 99 psec tubs have shat out their seals, and I need to find a replacement, I\'m trying to figure out if I\'ll lose power going for a \'regular\' turbo pack.

[HaywardRotary]

Turbos on 99 spec onwards are different in two respects.
1. the compressor wheels are more efficient with much tighter tolerances and slightly bigger.
2. The turbines have one less blade on them and flow better.
This equals more power.
Regards
Carl

[trotter]

Carl, is there no question too obscure that you can\'t answer? :Laugh

[SiH]

Nuts, that\'s me fcuked then, I\'d better get searching for some unicorn horn...
Cheers Carl

[Jovic82]

trotter i was thinkiing the exact same thing!, thanks carl

[DrDan]

Even more detail on the later generation FD Turbos here:
 
http://autospeed.com/cms/title_Last-of-the-Line-RX7/A_1962/article.html
 
To quote:
[INDENT]The availability of the 280ps engine in the Series 8 Type R and RS was certainly the biggest progression over the Series 7.
 
So what changes gave the Type R and RS a 15ps (11kW) increase over Series 7 twin-turbos, you ask? Well, the 9.0:1 static compression twin-rotor 13B remains largely unchanged, but its small HT-12 sequential turbochargers received smaller turbine housings and altered blade profiles. At the production stage, each turbine housing was also coated with an adbradable resin and the turbine wheel was then spun in order to shear way the excess resin. Once hardened, this dramatically increased the turbo efficiency. The 280ps motor also ran slightly increased boost pressure (11 psi) and slightly less exhaust backpressure. Exhaust flow was enhanced by using a thinner wall exhaust tube (to increase the internal flow area) and less restrictive mufflers. Even so, the factory exhaust has just a 1¾-inch ID, meaning massive power increases can be found with aftermarket exhaust systems.
[/INDENT]SiH, looks like it might be a bit of a mission to reproduce factory spec. turbos!!!
 
DrDan.