I have 5 dyno sheets and some log data for people to look over.

The car:
2005 GT trim, 83,000 miles on the odometer, original engine
COBB AP with 3rd step in MM CCS, BHR midpipe, OEM ignition coils with 3,000 miles on them, Magnecore plug wires with 21,000 on them (geez, it has been that long), plugs with 3,000 miles on them.

The conditions:
88F to 91F between the runs, humidity from 17% to 24%. Dyno's done at Lime Rock Park CT, I can't find the altitude, but the barometric pressure on the dyno was reading in the 29in/lbs range.

The dyno:
A trailer'ed Dynojet from Axelerated Motorsports out of Pittsburg PA

The Runs: (no, not diarrhea)
6 runs total. 2 on Friday, 2 on Saturday, 2 on Sunday
Each pair of runs was back to back.
#1 and #2 were done in 4th gear (No AP logs)
#3 and #4 were done in 3rd gear, (have AP logs from them both)
#5 and #6 were done in 3rd gear with the ABS/DSC fuse yanked (Have an AP log from #5)


Run 1 and 2:

RPM Data drop is clearly visible, ambient was 89F

Run 3 and 4:

RPM data drop again, though less drop. Ambient was 91F, and my car had been idling for about 15 minutes at this point, started it up, and 2 cars ended up jumping the line in front of me.
Run #3: Peak MAF was 192g/s, peak load was 88.98%
Run #4: Peak MAF was 194g/s, peak load was 89.77%

Run 5 and 6:

3rd gear, no RPM signal drop finally, ABS/DSC fuse was pulled, 88F
Run #5: Peak MAF was 204g/s, peak load was 95.26%

The logs:
https://spreadsheets.google.com/spre...thkey=CPTA08MK

And the MAF data for runs 3, 4, and 5, graphed against each other. (1 is 3, 2 is 4, and 3 is 5)




Another additional point that is making the results confusing, is that of the 8s we had there that dynoed (at least 8, I think more like 15, I wasn't there for all of the dyno'ing), Altspace's dynoed 175hp on the first run, lower after. Greenblurr93's Dad dyno'ed 135hp with misfires all over the place (ignition), but every other 8, with varying tunes (racing beat, MM CCS, stock, COBB stage1) cat vs no-cat, intakes, catbacks, BHR ignition vs OEM, engine mileage etc... Every other 8 dyno'ed between 158 and 169. Every single one. Several dyno'ed within 1hp of each other with a difference in mods that have been proven to improve power. (WinningRX8Chick, with BHR ignition, altered COBB stage1, BHR midpipe, borla cat-back dyno'ed 0.5HP off of another bone stock 8). So we are all largely confused by how that played out. The guy running the dyno had never dyno'ed an 8 before, and that may play a role.

 

my Dyno graph, done on Saturday. couple hours before RWIWP's dyno, its a bit cooler in the morning maybe low 80s ... if that even matters.



WinningRX8Chick ? You mean The beautiful lady with the Blue 8 right ? Hmm she has BHR ignition huh

 

Just so you know, that "jagged" shape after the APV opens is ignition misfire.
BHR ignition stops that.

 

Jeff,

WinnginRX8Chick also had that jagged line up there, and has the BHR ignition.

I was the only 8 that didn't, and only when I dyno'ed in 3rd instead of 4th.

Possible reasons?

 

I dyno'd in 3rd a few years ago and hit 183.

 

183.......g/s? mph? hp? tq? load? coolant temp? intake temp?


Sorry, have no idea what you are telling me

 

whp lol.

Sidenote: Asshat.

 

Here are results from a run on a Mustang dyno yesterday. Peak results were 181 hp @ ~8500 RPM & 129 tq @ ~5900 RPM done in 3rd gear.

Modifications include:
AEM CAI
AP under-driven crank pulley
BHR ignition system
Completed MazdaManiac tuning service



I have done stock dyno runs before on a DynoJet ( 171 hp / 128 tq -- https://www.rx8club.com/showpost.php...&postcount=404 ) and then later a Dynocom DC1800x on fresh ignition components ( 182hp / 135tq -- https://www.rx8club.com/showpost.php...1&postcount=19 ). Unfortunately this makes it difficult to realize any apparent gains. The reason for hopping around like this is because I took advantage of group events that offered discounted prices for the runs. Eventually I will go back to the Dynocom for another read and better comparison.

 

Wow what a strange looking graph at the top end.
Why did you do it in 3rd gear?

I thought most ppl did the dyno runs in 4th.

 

It seemed like it was taking forever to get up to redline with the load bearing dyno in 4th gear as they were calibrating things, so we decided to do 3rd instead.

I think they had a long line of people wanting to go as well, and wanted to expedite things a bit.

I believe my previous dyno runs were in 4th gear.

 

Got AFR for that?

Looks like your VDI is stuck open.

[EDIT] - I was just looking at the logs you sent over the weekend. Have you had your motor checked for compression?

 

No AFR, sorry.

I have noticed lately an occasional metallic rattle @ WOT around the VDI actuation range RPMs (around 7000s, I believe). I'll try poking around the manifold sometime. Come to think of it I think I've always gotten a bit of valve rattle on the SSV (or is it the APV @ ~5500 ?) before, too; thought nothing of it.

I have not had a compression check performed; nor have I really had any reason to. I have never had any problems with the motor; no CELs or apparent idling, hot start, hesitation, loss of power, etc. issues. I am currently just over 81k miles (all mine, original engine), and if anything plan to do a compression test near the end of the warranty period. What makes you consider compression from looking at those logs?

I have noticed an engine code scanned from the AP before (no CEL), but I don't think it's relevant: "RKE B1318", I think... will have to confirm later (confirmed B1318). I think the "RKE" refers to "Remote Keyless Entry", . It comes and goes.

 

FWIW, I just checked intake vacuum pressure to be about -17 inHg at idle (~550 ft. altitude). I pre-ordered TwistedRotor's v2.0 compression tester, so I'll have compression results eventually. Once I get around to it I'll take apart the intake to play with the valves.

 

I'd say none of the above. The power drops at that point when the VDI opens due to the airflow disturbance, which is shown on the graph. That wouldn't happen if it was stuck open. Power never gets back to where it was pre-VDI which would have never gotten that high pre-VDI if compression was the issue.

 

First ever dyno today went pretty well. Did it on a Dynojet courtesy of English Racing in Vancouver, WA

Mods: Corksport Cat-back, Corksport Catless single resonated Midpipe, K&N Panel filter.

186 RWHP
86 Degrees F
29.88 in-Hg
27% Humidity
1.02 STD

http://www.flickr.com/photos/6789243...n/photostream/

http://www.flickr.com/photos/6789243...n/photostream/

 

Looks like stock RX8's dyno below 180 whp. I have been looking into an RX8 as my 5th car in the garage as a track car since not all track event hosts allow a S2k without a full cage (bmw club).

 

they can range from 160-190 depending on the condition of the engine.

 

As a follow-up, I finally got the tester and have discovered my engine is marginally below spec.

 

I haven't driven an S2000, but I know the RX-8 handles better than my mildly modified 1997 M3. My first day out in the 8, I cut my lap time by 3 seconds. THe M3s were pulling on me in the straights, and I had to slow down for one corner for some reason I never learned. Upshot is the car cornered well enough in the other 9 corners to make up for both of those issues. I don't remember, but I think I dyno'd at 183 (it it posted here) maybe higher due to no cat and software.

 

I did test drive a RX8 from carmax, so not a good comparision. It did softer but did handle well. The speed/acceleration may have been the same but there was no VTEC(yo). The rotary engine was creepy smooth.

I driven modded FC and FD's, but I been wanting a 4 seater rotary since the chance of future of rotary is slim and I could also use it to haul babies in the future. Plus, I think the used price on these are a bargain due to the all the horror stories these cars get.

 

I had KW3s on it with R Compounds and track pads. Just had yet to figure out something with the lightness in that one corner at 120mph. I have 3 kids, so having more than 2 seats is a necessity. I miss that car more than anything I have owned or driven, which includes 2 supercharged M3s. if you have the money, get a 2006 or newer; ideally a 2009 or newer. Learn the idiosyncrasies and try to pay attention to anything else afterward! (Ok, I will admit a S2000 is on my bucket list, and a Cayman, and a 2012 Wrangler, but otherwise...)

 

I'm guessing that there is some kind of ignition issue going on here, would like to figure out what, though...





2007 with 17,400 miles. Original coils, wires, and most likely plugs. Running a K&N drop in, BHR catted midpipe, RB race cat back, Cobb AP with MM v4.02 tune, and an AP crank pulley.

Done on a Dynapack at pretty much sea level, 56F. The operator puled up another RX8 file to compare. That one made similar power sub 7k, but pulled strong up to 180 something at 8300rpm.

The other odd thing is the variance in torque numbers from run to run???

 

TQ numbers generally give a bad reading because our cars don't play well with the dyno. As for the rest of your issues... I dunno, graph looks fairly normal to me but I'm no expert.

 

yes - almost certainly. Gotta be one of the plugs , leads , coils trio .

 

Date Mar 8, 2012
Location: San Diego, CA
04' with 60K
Temp 65F
Mods: MM Turbo, turbo back RB racing exhaust, custom intake, *edit MM tuning
Dyno: Dyno Dynamics Dynamometer (Note: apparently this Dyno reads low about 15% lower)