wish I would have seen this thread last week! I'm looking at my Hymee cat back that UPS delivered at 8pm tonight. Might have screwed up getting it . My impression was cat backs didn't offer that much difference in horse power . Live and learn I guess!

 

I think a lot of us wish we had waited after seeing these results. But they are using a wider diameter pipe right? I think that may have a lot to do with the gains they are seeing, and no one else is able to get.

 

and they say there isn't much to gain out of a exhaust , measured the Hymee, 2 1/2 pipe. Don't get me wrong , the thing is beautiful , but man, $100 bucks more could have a mid pipe also , maybe after I get it installed I won't feel so bad.

 

bigger isn't always better unless you're going to FI though. Sometimes backpressure is a good thing for a NA rotary that lacks torque. But in this case that argument goes down the drain

 

Can't you return it and take the hit on shipping?

 

I'm not sure about the VDI zoom44, we've seen lots of guy on the dyno that peek before the redline then drop off. I don't think we coulda hit 190rwhp (best onlyracing beat catback run). If that duct didn't open.
For a VDI diagram look here: http://www.step-hen.com/images/6250.jpg

See my attachments below, first is a dyno from May when we were doing the REVI+more testing on my, the second phildox's greddy turbo 8, both show that lack off pulling past the redline. With just the RB catback it would drop off more harshly it wasn't until we put the racepipe on that it started to flatten the part where it it dipped down a bit.

As for the turbo-xs stuff real nice quality, true 3" all the way though breaths real nice the best run of just RB-catback vs. just XS-catback I believe the largest difference was 3.5-4hp near redline. Sound is much louder, deeper and more poppy, but not as annoying as others along those same lines. (uploading clips to my server now 50mb each no way to re-encode on this laptop)

1st clip RB catback
2nd clip XS catback
3rd clip XS catback + racepipe.

With the race pipe and XS catback the CAR is LOUD! just see soundclips, it sounds beastly, think drag race day and the PR rotaries are in town.

I believe the highest racing beat vs the highest XS+race pipe resulted in a 10rwhp gain up top, and around 5rwhp though the midrange. (nathan confirm)?

At the current the racepipe will not meet up with the racing beat exhaust, there is an issue because the RB exhaust tapers down to stock size where it meets up with the CAT pipe while the XS system is 3 inch all the way thought, the donut gaskets won't work.

Note* silencers were removed from the XS catback, mainly b/c they don't look good in there

everyone enjoy. On the plus side this is by far the best the car has felt after getting it off a dyno, great throttle response everything feels more responsive we think the ECU has up'd the advance a little bit.

 

polak are you in d.c this weekend? I have finals till friday but then i'm done. I havent had a chance to take a ride in a turbo'd 8. your car is turbo'd right cause i thought i saw about 240whp? Anyway you can check out my full exhaust system and i can see your turbo car if your around. let me know.

 

Read my post again its a dyno from phildox's car form the i think... Feb. issue of Rxtuner.

 

^sry i had missed that part...after going in nathans lotus and wrx i would just like to see how the 8 feels with a turbo

 

take the 172 rb run with a grain of salt is was the first run of the day after that one I think the ecu switched its thinking and started to advance timing.

The first sets of RB exhausts when something like 172, 185,186,187,188,190 so after that first run we were fairly consistant.

The Turbo XS just catback stuff was consitant as well something like 190,191,192,193,194

The XS catback with race pipe was even more so something like 194,193,194,195, etc.

Nathan email me those sceenshots when you get some time tomorrow mark87G@comcast.net

 

I have to give turboxs some props. Normally companies will dyno once, give you some results, and then thats it. I've never quite seen a company this involved with trying to get consistent repeatable results across multiple cars.

Dyno proven has a completely different meaning with these guys!

Has anyone experimented with richening the 8's fuel mixture prior to 5500 rpm? It stays in the 14's for quite some time before it dips down. I know this doesn't directly apply, but we richened the 6's A/F ratio about 1,000 rpm's earlier then stock, and picked up a heapload of low end grunt. Guess I should probably just read a few thousand old threads and shutup.

 

I thought about VDI some more and attaching a turbo 8's dyno isn't the best idea for comparison since phildox doesn't hold 8psi all the way to redline so its natural that the power will plateau.

Here is several NA dyno's all showing the same power curve I got at XS, pulling to about 7500 and then a gradual let down.
https://www.rx8club.com/series-i-tech-garage-22/dyno-results-compilation-77031/

 

fully operational and running correctly(no timing pull from over temp etc) the hp curve should look like this plot from a mustang dyno



if after 7ish k it doesnt continue upward like that then something is causing a loss of power.

btw 188 on a mustang dyno? thats really impressive

 

The shape of the above curve is similar to what we observed with Armaant's car. Polak's was almost dead flat from like 7000 to redline.

-Nathan

 

These are similar to what I got, honestly I just think the ECU is pushing alot of advance up to 7500 and then backing off but I could be wrong is that valve vaccume or electric charlie? Is there any quick fixes?

 

see that last one Mark- that's dmp's run yes? i would say that run has a problem. the power SHOULD continue upward from that 7250 point but does not. it stays flat. thats either timing being pulled because of overtemp or a VDI not opening. i would think timing on this graph as you can see the dip when the VDI opens it just doesnt ever recover poperly.

actually one other thing i think it could be is what nathan and i were discussing- loss of the rpm pickup resoulution causing incorrect readings. if the dynojet - which dmp's run was - looses that signal it does not give correct correct results

 

repost. sorry

 

This is my dyno w cz on dynojet before the recall flashed

 

dang 195 with just a canzoomer? nice

 

see those are good clean runs. hp rampsright up to 8500 like its supopsed to. before and after the cz

 

Four attachments here
1. Armaant's car: notice the 2 dips in the torque curve and then the rise to redline
2. Polak's car: notice the single dip in the torque curve and the fall off of power
3. A comparison between the two cars. Note the 25hp difference at redline
4. Polak's car with the RB system vs. the full TurboXS exhaust system.

 

see THAT looks like a stuck VDI to me.

nathan does it look to you like polaks car losses some T and HP below 4500rpm with your system?

 

I have several plots from his car. It was all over the place below 4500 on his car. I've got a few that look like it gained quite a bit down there as well, but the plots that I picked were meant to show the VDI problem the best.

-Nathan

 

thanks nathan

 

Here is a plot showing all 6 runs with the full TurboXS system on Polak's car. Notice the wide variation on the low end.

-Nathan