Aha, now I understand what you're looking for :).

For the 993S, the final drive is 3.44 : 1, and 4th gear is 1.12 : 1, giving a total ratio of 3.8:1.

For the 77, 4th is 1:1 and the final is an 8:31, giving a total ratio of 3.875. This is slightly different from the 993, but the operator was adjusting the ratios on the fly with the machine...he somehow used the machine to help define the ratios, and said he could determine the ratios in the gearbox entirely from the machine. I'm not sure if the numbers on those sheets reflect his tweaking or not.

Forgive my ignorance, but why does the HP not come close to that of the V-ram 993? Wasn't the US-spec V-ram 993 rated at 283hp? I would think the same engine in a much lighter car would easily top 300hp, no?

Although the charts say flywheel HP, the correction factor entered into the computer is 0, so it's rear wheel horsepower. If you use the 15% guesstimation for loss, my 253rwhp is roughly 298hp at the flywheel.

MM -

I would think your rwhp should be close to 270 with the Steve Weiner mods. My guess is this would be achieved with a Flowmaster or an exhaust of this sort - and perhaps a fix fo some engine issue (?)
O2 sensor?

I expect (!) close to 290 rwhp with the '97 Varioram, GHL headers,
Flowmaster, RS 3.8 cams & the Steve Weiner mods to ECU.

Craig
@RS
('97 Varioram installation in a few weeks!)

Craig,

While I figured my engine would be roughly 300hp, which it is, I suspect better performance lies in wait with a different final muffler. We'll soon know whether it hinders performance, after Todd finishes his dyno comparison! Your engine will be a monster, regardless!

Personally I feel that you guys are way too optimistic on the hp projections. The factory 993RS only achieved 300 at the f/w and they didn't leave much on the table though they may have published pessimistic #s for their own purposes.

Things they had that the 3.6 vrams doesn't are,[list=1][*]bigger valves[*]bigger ports[*]bigger intake manifolds[*]bigger displacement[/list=1]

About the only thing that can be improved is the headers w/ a slight tweek to the fuel/ignition maps to optimize the installed setup. The 993 exhaust manifolds are good but there are better choices out there, same w/ the euro fuel /ign maps.

Things that can be done to improve the 3.6 are similar to the above listi.e.[list=1][*]bigger valves[*]bigger ports[*]bigger intake manifolds[*]bigger displacement[*]better headers[*]optimized chip[/list=1]

There is a wealth of additional dyno data collected here Mostly 964 stuff but there are a # of 3.8RS data points included. Almost universally the collected data shows more than factory ratings, similar to what we are seeing here.

Bill, I was thinking that the muffler might have an effect on my low-end torque numbers rather than the peak HP. Thoughts?

It's hard to tell w/o a comparison. I don't like the way the L/R banks hit head on in the lower mixing chamber of the Triad, in the Flowmaster there is a similar but less severe confluance. It would be really informative to do a back to back. I am planning some dyno time at Rick Demans some time this spring. One thing that I would like to check is the Flowmaster vs twin Coasts. The twin Coasts seem to perform very well on the cars that have them, but then the cars tend to be very well setup all around.

MM-Your car and 2 or 3 others have been the inspiration and learning points for what I will do with my engine.

I base my projections on readings published here via Dynojet 248C results of 269 rwhp with:

Factory 993 header/heat exhangers
Good muffler - no cats

My engine will also have RS 3.8 cams, & a Flowmaster muffler.
I'd expect 10 or 12 more hp from the cams alone, giving approx 270+ rwhp Dynojet 248C hp. THere just isn't much more one can possibly do to these 3.6 Varioram engines - as Bill said, not much left on the table!
For this reason alone, I just may keep the 993 heat exchangers.....

Craig
@RS
79SC with Varioram install coming in a few weeks

Also, I just posted the "story" on our Dyno Day, including plenty of pictures & graphs.

GTC Motorsports

Click on "War Stories" on the left, then you'll see dyno day as one of the choices.

There are plenty of additional pictures in the Gallery Section. Enjoy!

Because of my O2 port I could see into the mix chamber of the muffler and the flow of the L/R banks is internally split somewhat, probably not enough.

While I truly love the Triad sound, I think what Bill has described may be taking a little bite out of the top end. However I don't believe the Triad is hurting the bottom end one bit, I am coming close to 4 secs. flat 0 to 60 (as measured by the G-tech) and I am not launching it as hard as I could. It was a VERY fun afternoon in the Buckeye state today..:D

I am going to try and do three dyno runs with the 993 cat w/turndowns and three runs with the triad.

Rob & others:

What the heck do I use from the end of the Thom Fitz CF tube where the CF tube enters the sheetmetal -- what setup do I need regarding:

What is the part/part number/model from used to where the *bottom* of the CF tube attaches?

Actual sheetmetal (model, etc?) where the tube assy enters the sheetmetal?

What is used below the sheetmetal with regards to an air splitter?

In other words, what do I use from the end of the air tube where it enters the sheetmetal - that is, starting under the sheetmetal and leading to the heat exchangers?

Craig,

I have custom setup with sheet metal adaptors & what not running to the tube. I wasn't able to use the factory aluminum heat tube, thus my odd setup.

You can see some routing on page 4 of this thread , or more detail on this heat ducting thread.

Does that help?

It does - but do you have pics of the area and assemblies from the fan, through the sheetmetal (what sheetmetal did you use??), and what on earth would I use to split the air - shop fabbed one? Do you have pics -

This sucker goes in in 1 week ;-) & in the meantime the RS 3.8 cams go in...

THX
Craig

Those are almost all of my pics of the area. I'll see what else I can find, and I'll try to remember to take some pictures tonight, but I don't know how much more you can see without removing things.

I used stock 993 sheet metal, slightly modified to fit the bay.

Ah, cool - that helps with the 993 sheetmetal info.
I'd love to know what air splitter dealie you have/was fabbed -

THX
Craig
@RS

Just one note when talking dyno #'s, to even be in the same ballpark with numbers and curves, you have to be talking the same types of dynos (dynojet vs. dynojet, mustang vs mustang, dynapack vs ....). Secondly your numbers are going to vary depending on tranny temps, engine temps, ambient conditions etc. So basically 250 vs 260 vs 270 on a dyno are all relative numbers. An interesting article:

http://www.caranddriver.com/article...article_id=8020

Brad

Yup. I've found one Dyno to have fairly repeatable #s - the Dynojet 248C - from unit to unit, the #s are very close.

Artcle link:
http://www.caranddriver.com/article.asp?section_id=4&article_id=8020&page_numb er=1


Craig
@RS

Jack,

What about 3.0 to 3.2??? (full motronic conversion, not rebuild) Or, just do the 3.6 and be done with it??? Decisions... decisions...:cool:

Very nice on the v-ram.. It's so tempting... $$$$$

Not sure it's a helpful comparison because it's a different dyno on a different day, but here are my results with stock HE's and a custom Magnaflow dual out exhaust (Cyntex chip):

http://forums.pelicanparts.com/uploa...1083798837.jpg

I didn't dyno with the cat only. This probably isn't conclusive regarding the effects of your Triad in comparison, but might be incentive to try other setups.