Miata Mailing List: September 1998, Message #103

sponsored by

Hi all,

The following is my post to the local autoX list. I think it's worth
forwarding it here as I want to tell the story of a 300 rwhp 3rd-gen RX-7. 
I also want to take the chance to ask the list wisdom if an SAE-corrected
103 rwhp @6800rpm, 90.3lb-f sounds low for my 1.6L with RB header, JR
cat/catback and cone filter with home-made smooth-transition
square-to-round opening funnel adaptor. 

P.S. The name Minnam Racing should be familiar to some of you on the list
for their 300hp '93 LE.

On Tue, 1 Sep 1998, Chris Chu wrote:

> 
> Hi all,
> 
> Finally my ISP has finished upgrading the system and I'm back on line. 
> Last Sunday Minnam Racing held a FR*E (don't know if the list server will
> remove my post if it contains the full word, some lists do) dyno day.
> These guys were doing a great job. Think about 6-8 people spending the
> whole day (8am to 8pm) non-stop strapping/unstrapping 40 or so cars for
> dynoing on a business day (and a very hot day).
> 
> My '90 1.6L miata with Racing Beat header, JR hi-flo cat, JR 2-1/4" 
> catback, Akimoto-style Cone filter, and 4/6 deg in/ex cam retard was able
> to reach 103hp at 6800rpm with 90.3lb-f at the rear wheels (stock 116hp
> @6600rpm, 100lb-f @5500 at the crank). Terence mistakenly turned the
> adjustable cam sprockets the wrong way which facilitates low/mid end and
> got 117hp @6600rpm. No wonder why he got a lower rpm than I did.  From the
> result of my home-made dyno system and my sunday result on the dynojet, I
> estimate Terence's car should be able to achieve 120hp at about 7000rpm
> with the right cam-gear setting. 
> 
> The hi-lite of the day must be Don Nimi's 3rd gen 20B-based 3-rotor
> normally aspirated RX-7. Extra care was taken to strap down the beast.
> The engine seemed to have tuned-in better than last time I saw it at
> Mission Raceway -- 3 ft long of flames shooting out of the exhaust pipe
> every time at turn 7.
> 
> Everybody was very excited, standing at least 20 ft away from the exhaust
> pipe in fear of getting burned (no kidding). Although we didn't get to see
> the flames again, there was another great scenary. As soon as Andrew (at
> Minnam) full-throttled the beast, we saw two trails of sparks going off
> the rear wheels like putting 2 running circular saws on the dyno roller
> (no kidding, should've got my camcorder there). I think that was caused by
> the sand and little stones got stuck on the tire surface. The exhaust flow
> was so great that it almost blew the banners off the wall 30ft away. Now I
> know how much is 300 normally aspirated horsepower at the rear wheels! 
> 
> 

--
Chris Chu and Shirotora
'90 Crystal White
http://infomatch.com/~cchu/
--