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How much of an impact do you think removing the rest of the catalyst had on the results?
Would be interesting to see what a manifold with separate runners of the same size you're using now routed into a merge collector would produce...something like Team's latest design. I suspect that some portion (perhaps small) of the flow from the back 2 runners tries to initially go forward when it first enters the log. If that does happen, I would expect a merge collected manifold would eliminate that problem.
Yeah .... that was something unexpected ...after the initial great result...... I just expected the cat to be already gutted ...... when it wasn't we thought we might see an amazing final result. Then when it didn't come it was like .............. what the actual f**k !!
Comparisons aside ..... I have a 220whp NA Renesis , which is pretty damn cool !!!!!!!
I have no idea what was done to the engine when it was rebuilt but someone built a good one !
Hopefully there’s a different dyno around you can use. The rolling motion of the data leads me to think it’s dyno induced. My car doesn’t have DSC, but I suppose there could be something going on with that too.
I'm not sure what the deal is with the DSC .... today it turns on and off like normal . Yesterday the squiggly line and abs lights were on but pushing the DSC button was doing nothing. This might actually be normal when dynoing an 8 with DSC and I've just never been the one to hit the button before ....
What's your feeling about the cat chamber ? I had the thought that it might be a good thing as it would dampen pulses before they enter the smaller tubing but not so sure now.
It’s all about the transitions. Without a long angle transition on the inlet it’s probably better to replace it with straight pipe. However, is this an OE cat pipe? You really need 3” all the way from the manifold to the tailpipe or have it split into dual 2.25” or 2.5” at the rear to get a free flowing exhaust.
It’s all about the transitions. Without a long angle transition on the inlet it’s probably better to replace it with straight pipe. However, is this an OE cat pipe? You really need 3” all the way from the manifold to the tailpipe or have it split into dual 2.25” or 2.5” at the rear to get a free flowing exhaust.
Yes ...I know 3" is the way to go . I'm trying not to spend too much on it plus I like the tone of the setup as is for street. Just wondering if any benefit cutting out the cat expansion chamber and running 3"OD to the stock resonator , which would be relatively cheap to do. The resonator is actually 65mm ID then it goes to 65mm OD tube from there. so it would be decreasing from 72 ID down to 65 through resonator then 62 from resonator back.
Well it’s a moot point to eliminate restrictions at the manifold only for them to be manifest further downstream. Especially if you intend to gain power by porting. Sort of like chaining a lead ball to your ankle just prior to starting a race.
It’s all about the transitions. Without a long angle transition on the inlet it’s probably better to replace it with straight pipe. However, is this an OE cat pipe? You really need 3” all the way from the manifold to the tailpipe or have it split into dual 2.25” or 2.5” at the rear to get a free flowing exhaust.
so this is what I was referring too above. This is the HJS race cat converter I was using. The catalyst OD is a little bigger than 6” OD (153mm) with the long angle from 3” OD pipe and then it can have a steeper angle on the rear discharge cone back down to 3”. So it’s more like a megaphone type expansion chamber. The flow will be disturbed and restricted more just dumping in/out of an open chamber
Glad you’re doing this for all of us novices’ out here in real time. I don’t like reading threads from 5-10 years ago when a lot has been discovered since then.
I can follow your lead if you make some real new discoveries before slapping a turbo kit and blowing up my first engine. Saving us money and time.
glad I have my Camry for the daily so I can really start my own tinkering on the 8 when done with school.
Thanks for doing this, information is priceless
Last edited by 40th8Jake; Nov 26, 2019 at 01:37 PM.
Next step : taking it in to get the cat cut out and a 'stock' resonator put in it's place. This should help deepen the tone and get rid of the hollow sound it has (coming from hollowed out cat we think).
Also : In talking to the muffler guy ..... he suggested that having the exhaust gradually reduce in size slightly over it's length is not necessarily a bad thing . Theory is : as the gasses cool they require less area to maintain the same velocity and therefore backpressure is no worse than the larger pipe.
So will be sticking with the system I have vs spending 2k on a 3" system that I suspect will show minimal gains over the 65mm system I already have.
Taking engine components in to be assembled this morning.
This application is the exception though, because like everyone else; he has no reference experience for a zero-overlap engine situation. Again, it’s all about total flow only and in order to maximize porting potential this is needed even more so.
I'm not sure what the deal is with the DSC .... today it turns on and off like normal . Yesterday the squiggly line and abs lights were on but pushing the DSC button was doing nothing. This might actually be normal when dynoing an 8 with DSC and I've just never been the one to hit the button before ....
.
Just to add to this .... I've since found out .... if the squiggly line light is illuminated ...you lose the ability to turn the DSC on and off with the button. So what I saw on the dyno was normal and DSC must have been disabled.
Just to add to this .... I've since found out .... if the squiggly line light is illuminated ...you lose the ability to turn the DSC on and off with the button. So what I saw on the dyno was normal and DSC must have been disabled.
Whenever I get the squiggly lines and no "DSC OFF" I have to reset the power steering by going lock to lock (can't remember if left-right or right-left, or if it matters) before I can get the button to function normally again. Happens a fair amount when you're disconnecting the battery a bunch or draining/jumping.
Edit: to clarify, whole procedure is
- turn on/start car
- lock to lock
- turn off.
Upon restart it should be good to be re-toggled, or fully disabled by doing the 7 second hold. Once the hold is done, I don't think you can turn it back on without restarting the car. At least I haven't found a way.
Last edited by bwilk; Dec 4, 2019 at 03:50 PM.
Reason: clarification
Got the extra (stock) resonator fitted today . It has definitely improved the tone to something I'm happy with . Didn't really make it quieter but it is deeper and with none of the hollow sound it had.
Got the extra (stock) resonator fitted today . It has definitely improved the tone to something I'm happy with . Didn't really make it quieter but it is deeper and with none of the hollow sound it had.
Heh
Well , the new engine will be ready before xmas but I wont be fitting it till late January . In the meantime I'm doing cosmetic stuff to it in readiness for use as a wedding car ....So yeah ...big yawn for now.
Heh
Well , the new engine will be ready before xmas but I wont be fitting it till late January . In the meantime I'm doing cosmetic stuff to it in readiness for use as a wedding car ....So yeah ...big yawn for now.
Do Aussies drag tin cans behind their wedding cars? Or just straight-pipe their rotaries?
Next step : taking it in to get the cat cut out and a 'stock' resonator put in it's place. This should help deepen the tone and get rid of the hollow sound it has (coming from hollowed out cat we think).
Also : In talking to the muffler guy ..... he suggested that having the exhaust gradually reduce in size slightly over it's length is not necessarily a bad thing . Theory is : as the gasses cool they require less area to maintain the same velocity and therefore backpressure is no worse than the larger pipe.
So will be sticking with the system I have vs spending 2k on a 3" system that I suspect will show minimal gains over the 65mm system I already have.
Taking engine components in to be assembled this morning.
I think this makes sense especially since there is not any forced induction. Only then do i think doing a full 3” makes sense.
Heat excites molecules needing more volume i believe so it works out.
M=V/D and if you get scientific and measure the temp of the exhaust gas at header, then at tailpipe , you can calculate it...but a dyno will do all that without the maths.
Last edited by 40th8Jake; Dec 7, 2019 at 03:55 PM.
Yep ....despite what Team says ..... I just don't think i'll gain anything much over a system that is free flowing anyway. Not to mention it made great hp already!
Well of course he *thinks* that, just like everyone else based on theory they know and love, but doesn’t apply here.
we could rehash the same old stuff again like Formula Pro Mazda/Renesis race cars having a short primary into a short, open 3” muffler and pipe
rather than all that bundle of snakes stuff they know so well and could easily build as well as lighter smaller diameter piping, muffler, etc., but why bother when people will just keep ignoring the obvious and insisting otherwise.
like I posted earlier, best output across the entire powerband would be the primaries dumping into the megaphone dumping as short as possible. Maybe even just short, open primaries. Because without exhaust pulse tuning the least amount of exhaust restriction always wins when combined with intake resonance tuning. It’s just common sense once you learn to let go of everything you knew before and see it for what it is than what you incorrectly imagine it to be.
....So yeah ...big yawn for now.
Shoot, botched that one. Gotta remember all Aussies drive RHD's, but not all RHD's are Aussies.
