man it never ends, eh?

LOL you ever wonder how it all got started? Anyway how are we looking for our next Dyno Day?

ok for me i guess. i've been datalogging and such and have some open questions but am happy to jump on the dyno anytime..

Still working on the spring issue? I still need to tune the BC.

and still going strong :)

It will end when I run out of money I guess! :eek:

My ACT clutch looked new when we put it on the new engine also. The only item that changed, was the flywheel. Now should I put my 12 lb Mazdaspeed back on? And take off the 9 lb ACT Prolite? Can't believe a flywheel is causing this. I'm just going to drive it this way and see what happens... :dunno:

Long distance clutch shipment from Florida to New Zeal? Did Scott's shipment include a bottle of Patron with it?

you know what's scary is that even after all your playing around with the clutch and chasing weird noises i still want to start tampering with mine. ;)

well i have it wired per the pettit install instructions now so it'd be nice to dyno and see what it's doing. what i really need is a good way to log boost.

Swoope - you didn't tel me this was customary ?!!!!

We use to use the 9 lb ACT flywheel and ACT pplate for years in Grand-Am to meet the 80% rule. I recall this same issue a few years ago and totally had forgotten about it.

Apologies in advance but I'm thinking about a long diatribe of wacky info I've learned in racing over the past few years of dealing with experts in the field. Perhaps you can can this a brief intermission while we all eagerly await the dyno visit(s). My gut says a knucklehead or two might respond to this and agrue about how his XYZ Ninja400 ultra lightweight such and such is way better than the Mazdaspeed P/N I3HIFIFHFODDIF-39389834 Rev. 17 with the Fujiyama anodized clutch bolts greased with Mobil 1 racing clutch bolt wax.

Less rotating flywheel, clutch and pressureplate mass is always the hot ticket. Proper data for measuring these values are represented in "Moment of Inertia" value and not weight. Weight is important but it by far does not get you to the meat of the story. You can have a lighter weight assembly with the weight located on the OUTSIDE of the flywheel/ring gear/clutch pack/pressure plate and it will provide less benefit than a HEAVIER assembly with weight concentrated at the center of the rotating assembly. In otherwords, WEIGHT is not the real value to look at. Unfortunately it is what the marketplace buys and what they are educated on. The purpose of this thread is to shed light on this subject. Very few people already understand what I'm going to share except a few smart guys on this forum. In deed they will also tell you that this is the only way to understand rotating items and put them in the proper perspective. SMALLER is generally better. Lighter is good but smaller is better. This is why you see smaller clutch packs (4.5 and 5.5") in high performing race cars. There is a quantam leap in performance gains when you get away from a stock size pressure plate and clutch assembly. Quantum. Generally speaking these smaller, lighter and greater benefit rotating items are for RACING only and the reasons why are for another time.

Flywheels typically come in Aluminum or Steel. Pressure plates typically come in OEM, 7.25, 5.5 and 4.5" size diameters in Alum or Steel. Some of these items are light or ultra light weight and can have a disposable life span. Most racing flywheels are aluminum and have a steel outer ring gear (the most outer portion of the flywheel with the teeth that the starter gear contacts). VERY few custom have aluminum ring gears (less weight on the outside of the rotating assembly) and will last for a couple dozen starts (the engagement of the steel starter gear to the alum flywheel ring = chewed teeth).

Just for reference, we run a 5 lb aluminum flywheel and a dual disc tilton 5.5" clutch pack (looks like this): https://www.rx8club.com/album.php?al...pictureid=8796

Our entire assembly is less than just the stock RX-8 pressure plate. MORE IMPORTANTLY look at where the core of the mass is located---toward the center. This is the hot ticket sports fans. Read the Moment of Inertia (MOI) info before reading the links below. It will help you learn something (assuming you want to learn something). The OVERVIEW is a nice little quick write up to understand the concept of MOI. If you want to learn something about flywheel and clutch weight then this post is probably right up your alley. If you like to argue and want to set up a group buy of carbon fiber shift nobs please go to the "will it fit" thread and read every single post 3 times.

Moment of Inertia layman definition:

http://en.wikipedia.org/wiki/Moment_of_inertia

Now, let's apply this MOI to high performance clutches. For this example I am using a clutch pack or clutch assembly. This is a combination product of a clutch and pressure plate type concept. It is and it isnt. But for purposes of comparsion there are two assemblies in these type racing designs: 1. A flywheel and 2. A clutch disc/basket assembly that holds the disc. Stock systems are a 1. flywheel, 2. clutch and 3. heavy ass pressure plate. The main advantages of the clutch pack product are it's condensed size, weight and ability to rebuild it. Clutch discs are like mini frisbies and are considered consumable. Stock type clutches are more of an assembly and get tossed out in their entirety when used up.

7.25" Twin Disc sintered metallic Clutch Pack. 7.25 is a great size to go to for a trailered NASA open track car. Inexpensive. Great benefit. Big gains over stock OR RX-8 AFTERMARKET size and weight).

7.25" size is 7.5 lbs, MOI: 66 The key data point is the MOI value of 66. Keep in mind that this thread is going to focus on MOI from here on (re-read Wickipedia if you need to recall why MOI is so important).
http://www.tiltonracing.com/pdfs/79.pdf



Compare this to 5.5" Twin Disc sintered metallic clutchpack (similar specs but smaller size)

5.66 lbs, MOI 29
http://www.tiltonracing.com/pdfs/64.pdf


Also notice on the 5.5" drawings the MOI value: 29 Quick math shows the 7.25" at 33% heavier than the 5.5". But more importantly look at the MOI values: TWICE as much for the 7.25"!!!!! So 1/3 heavier but TWICE AS MUCH MOI. HUGE!!!!

NOW, let's get crazy. Carbon twin disc. MOI 17.8 (approx $4,000+) Welcome to the big racing big leagues. 7.25 is over 300% higher MOI with a 3.7 lb weight. 3.7 lbs for a CLUTCH AND PRESSURE PLATE FUNCTIONING ASSEMBLY AND ALL THE WEIGHT IS CONCENTRATED AT THE CENTER OF THE ROTATING MASS and over 300% better MOI. I can't find (and I don't think it exists) any MOI data on stock or aftermarket clutches and pressure plates. As you could expect, MOI benefits would be MASSIVE.

Hope this has been useful to some of you.

http://www.tiltonracing.com/pdfs/60.pdf

I'm really not motivated to go find out the weight of aftermarket clutches and clutch packs but I think you can see the magnitude of MOI values when weight is concentrated at/near the center axis.

Cheers, gotta boogie. Meyer out.

nice write up. thanks!

Eric - I come to Indy several times a year on business. Might look you up one day and poke at your ribs a bit. I'd like to see your setup there if possible.

Now, if we can just secure a day to return to Carb Conn in Seattle. Dan, how is your project looking?

Shop is near downtown. Stop on in. Tuesday is ladies night. Women drink free from 8 to midnight.

It's not :( Family crap = no time. I need to take a week of to work on the car :)

so do it! ;)

when are we thinking dyno day then? still the 29th or is that too soon?

Bump?

DYNO IN 3 DAYS!

haha :yesnod:

JEALOUS! i wana go! goddam work

What happened at the dyno ?

Same results - up 24 to 26 over a stock block

I ran our of gas...And complained about it for a while....Shared some oreos...

I don't know what stock is. What did you pull and did the porting work reveal additional power in different parts of the rpm range?

After a few years of listening to people hypothesize about porting gains I've yet to hear any substantiated data. Help!

Consider this: I was the first on the dyno that morning at 9AM, so I broke it in for it's daily duty. 59.04 F, 29.88 in-hg, 66% humidity, SAE 0.97

182.84 / 125.61 4th Gear Pull
186.23 / 129.87 5th Gear Pull

Nice AFR all the way to the limiter thanks to Jeff Abrams.

Next up on the dyno after me, was an OEM stock RX8 engine. It hit 162 rwhp. (Missed the torques numbers for a few cars.)

Third car up, had a CAI and Catback RX8, hit 168.

Fourth up was Dondo's supercharged 8. And it is still giving him fits. Hit only 236.

Fifth car up, Dondo rolled up his Porsche Cayman S and lit up 284/248.



So, Engman's engine build, plus Jeff's tuning, has resulted in roughly 24-15 more rwhp than the stock engines this day, on a DynoJet two wheel drive dyno 4th Gear Pull. (Remember in Portland I was 26 rwhp over the the stock '09 RX8. Compare the #1 and #4 cars from that post.)

I have my dyno graph, and will scan it and post it on Monday. I think my restrictions to power can be traced to my exhaust setup: Racing Beat Header, Racing Beat Straight Midpipe with the Davesport 100cpi cat, and the BHR Resonator welded into it, then on to the Racing Beat REV8 dual can exhaust.

So yes, still not enough data to give street porting a good name yet for the Renesis. Hit around 233 g/sec. I'm not giving up yet, as I will build another exhaust setup this Spring. Then I will just follow my signature comments and turbo the dang thing.

It is a solid engine - sounds really awesome at revs and speed. Need to figure out the ACT 330lb clutch. I can still create the ticking noise.

Kevin

Awesome! I didn't have the stamina to read through all 33 pages, but I haz a question...



What did you do/ How did you connect the third oil injector on the 09+ housings?

The housing is not drilled for the third injector. Still only two per rotor.