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That's interesting.  There's less going on inside there than I might have imagined.  From experience with trying to make similar things have decent distribution, I thought they might have some lumps and bumps on the floor &/or roof.

On 17/02/2018 at 11:52 PM, GTSBoy said:

Plenty have done it and plenty say it's fine.  Many of those engines may have died, and you wouldn't hear about it if the plenum distribution was to blame because then the person who claimed it was fine would have proven themselves wrong.

But....I must stress, I don't know that it's not fine.  I only have very strong suspicion that it's not, because those plenums are not set up to receive air for all 6 cylinders from the front end.  The internal shapes are set up to receive it from the side.  I'm enough of an aerodynamicist to be very leery of that.  And I have never seen anyone report on 6x EGT probe results showing that it is fine.  On that basis, I simply wouldn't do it.  I'd be less worried about the various large plenums that bolt onto the bottom half, because at least they are simply big arse volumes on top of the runners, with no odd internal shapes to interfere.

I was reading through the thread and was going to weigh in anyway, though looks like you're very much on the page I am reading from - so I'll +1 with with a bit more anecdotal evidence to support it :)

In general tuning I think a fair bit gets covered up by people running "rich" mixtures, I actually think a lot of the target AFRs people tend to run with modded RBs (and other motors) are actually masking/to mask these trims from front to back with some types of plenums (and other parts sometimes) - albeit not necessarily deliberately, and often as a roll on from when people tuned on pump gas.

What would happen is people would tune and get knock or just from experiences of damaging motors in the past they'd run to something like 11.5 or richer (* results may very, just picking a number people can associate with to make a point), when in fact if you had individual lambda you may actually find that in some cases some cylinders could have been easily as much as 5%+ leaner than the mean.

The trick here is that for that to happen, that cylinder is actually seeing 5+% more air - so while people often see it as "it runs lean"... what that actually means is it is getting a significant amount more airflow, so the timing is also going to be more aggressive for that cylinder, and the power level is also going to be 5%+ higher than the "average". 

Lets say that such a motor is tuned on 24psi, and the target AFR is a 11.5:1 - then this is what effectively happens when one cylinder is getting 5% more air than the rest:

- It's own AFR is 12.08:1

- It's "load" is arguably pretty similar to if it was running ~26psi, but it's receiving the same timing as the rest of the cylinders

- If the dyno is showing 400wkw, that cylinder could be developing enough power to contribute to making 420kw+ @ wheels while being tuned aggressively (compared to the rest) to do so

This is a car which would probably be pretty reliable, and potentially actually be not a wildly rare outcome... it's just that ignorance is bliss.   Stuff like this is why it irks me when you get people on the internet criticising a dyno plot's AFR trace etc when they have no idea what the tuner has done, what they are responding to etc - sometimes the tuner has covered a LOT more than some dude on the internet who knows some rules of thumb could even conceive of by just glancing at the dyno plot.  Sadly, sometimes a lot worse can also be true.

It is technically correct that "these cut and shut plenums work" however, as air is getting to the engine.  That's what they're there to do and they'd have to be a pretty big fail to not succeed at that task.  Essentially they just have to seal and let air to the right place, there is ALWAYS going to be turbulance and weird acoustic affects meaning that fill isn't working exactly as you'd expect it.  Engines don't run in a beautiful constant flow way, but a better design will minimize the clutter - a crappy design / cut and shut will not.

At the end of the day if you have a poor design then your engine will not be as reliable or perform as well as it could as there will be situations where the moving parts attached to one cylinder are doing much more work than the moving parts for another and the harder your motor is working the more strain your motor is under for no gain than it needs to be as in effect - your motor is only going to last as long as the bit under the most strain can handle.   

If all 6 cylinders were doing withing .5% of the one working the hardest then you have the potential to make quite lot more power with much more response etc and no more strain on a single point than one with a shitty plenum.  Same goes for manifolding etc as well, of course.  It could even be an argument against low mount twins where both turbos clearly don't get perfectly identical inlets and exhaust paths - given the turbines have a direct influence on engine flow and they work independent to each other, I do wonder how much that influences things when driven hard...

Anyway.  Buy good parts, use a good tuner,  get good results :)

Edited by Lithium
  • Like 9

Big thanks for Lithium  for the information above.

Some video footages from Cam Martins car last week. R33 GTST powered by one of our ATR45SAT turbocharger making 320rwkws Pump externally gated. 

 

  • Like 2
  • 3 weeks later...

Some vids from Vicdrift round 1. We've taken first, car's powered by one of our ATR43G3SAT turbochargers, pulling 360rwkws on E85 fuel externally gated stock engine.

 

  • 2 weeks later...

Race car back on dyno again. This timing making 328rwkws using an our high flowed OP6 turbocharger internally gated. factory standard Rb25det engine with bolton supporting mods. Runing e85 fuel

car1.jpg

power.jpg

boost.jpg

  • Like 3
  • 3 weeks later...

Some videos to share from Victoria Time attack,  we've taken 3rd in street class and first in the fast RWD series. Car is above, R33 GTST stock engine running one of our high flowed OP6 R34 turbocharger making 328rwkws internally gated on E85 fuel. 

 

@hyper-gear Your recommendation for fastest spooling 300rwkw capable turbo for an SR20 on e85 with all the usual supporting mods?

undecided on cams or compression at this stage. considering options from stock manifold with ext gate welded on through to a "decent" stainless TS manifold but still open scroll turbo and gated. 

Comp will either be 8.5:1 or 9:1, I'll try and get some info about pros and cons, I know the higher comp will bring a bigger turbo on sooner. 

Considered things like GTX 3067/71 and EFR 6758/7163.

Dedicated track car, response matters as does linear power. 

 

@hyper-gearHi stao,

My r33 turbo sounds like it's on its way out and have been looking at your g2 350hp profile hiflow, that works with stock ecu/piggy back 

Have you ever made these with a BB core? I understand that these would already be quite responsive but I'd rather pay extra for slightly faster spool and improved partial throttle response.

 

I have been looking at HKS 2530 equivalents with the magic 100kw@3000rpm but obviously your option is financially more viable. 

Attached is the current tune I have on a stock turbo (red run) and normal supporting mods/piggback, so aiming for a replacement turbo with similar response.

 

 

 

FB_IMG_1523946372486.jpg

Edited by Pattey21

Super-Drager: Anti surge sleeve is ready but I haven't had too much time on it in further developments as I'm trying to get everyone's order completed for the time been.

Action Dan: For a super responsive 300rwkws E85 turbo I recommend our ATR28SS15 BB version. Result taken from a track car with built engine with 272/12 cams. No VCT

power.jpg

 

Pattey21: R33 G2 profile is recommended to run in a bush bearing setup, the configuration I use is already very responsive the way it is, which hits 20psi just before 3500RPM. I Can make it bb if you prefer.   

  • Thanks 1
16 hours ago, hypergear said:

Super-Drager: Anti surge sleeve is ready but I haven't had too much time on it in further developments as I'm trying to get everyone's order completed for the time been.

Action Dan: For a super responsive 300rwkws E85 turbo I recommend our ATR28SS15 BB version. Result taken from a track car with built engine with 272/12 cams. No VCT

power.jpg

 

Pattey21: R33 G2 profile is recommended to run in a bush bearing setup, the configuration I use is already very responsive the way it is, which hits 20psi just before 3500RPM. I Can make it bb if you prefer.   

Okay great. Is ball bearing not recommended as you find bush response enough/minmial gain or you run into surgeing issue when going ball bearing.

 

Cheers 

28 minutes ago, Pattey21 said:

Okay great. Is ball bearing not recommended as you find bush response enough/minmial gain or you run into surgeing issue when going ball bearing.

 

Cheers 

Ball bearing will have much better transient response, you can alleviate surging with lower DC when coming onto boost.

  • Thanks 1
21 hours ago, Dose Pipe Sutututu said:

Ball bearing will have much better transient response, you can alleviate surging with lower DC when coming onto boost.

Yep definitely would like to keep the crisp transient response. 

DC?

 

With the bush bearing recommendation was referring to the Rb25det 21U G2 high flow. Mainly because the housings are small enough to generate a very responsive out come, BB or not doesn't make much differences. But for anything else BB is recommended. 

 

Super-Drager: Anti surge sleeve is ready but I haven't had too much time on it in further developments as I'm trying to get everyone's order completed for the time been.
Action Dan: For a super responsive 300rwkws E85 turbo I recommend our ATR28SS15 BB version. Result taken from a track car with built engine with 272/12 cams. No VCT
power.jpg&key=b4982ae3fdedcd90332c9145eea4930035b118767e236f7f2fcd698871680dbc
 
Pattey21: R33 G2 profile is recommended to run in a bush bearing setup, the configuration I use is already very responsive the way it is, which hits 20psi just before 3500RPM. I Can make it bb if you prefer.   
Nobody else seems to see 300 on the SS15, is it manifolds and cams making the difference?

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