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Looks like the change to the 44mm Tial is a success ! Can now hold 3psi all the way to the redline . Previously the minimum I could get on the 3582 was around 7-8psi at redline. So boost creep ...eliminated ! This will allow us to run any boost level we desire plus the added bonus of being able to quickly dump boost if any alarm is triggered.
Log 2500 to 8000rpm on 2.9psi spring :
Those are the results we're looking for! Good to see the boost creep sorted. Time to turn up the boost?
So yeah ...turned up the boost to 9psi . This will be as far as I go on pump gas/stock engine.
Spoolup ..... definitely better with this cast manifold than it was with the fabd manifold and same turbo combo.
Boost control ... good but losing around 1psi up top . I'm sure it will be better with a 5-6psi spring vs the 3psi one that's in there now.
Power ..... making over 300whp at only 8 psi .... had to back off the boost cuz it was spinning the tyres during a run at only 9psi (crap tyres).
So yeah ...turned up the boost to 9psi... Power ..... making over 300whp at only 8 psi .... had to back off the boost cuz it was spinning the tyres during a run at only 9psi (crap tyres).
Excellent progress / result. Looks like a compact and effective design.
It w/b an exciting development for our RX8 community to have a viable mani & motor mount combo on which to base their build.
Ok , so far the manifold/wastegate combo seems to be working great, but I haven't talked about a couple of other things I'm testing :
New 8" vertical flow intercooler : This seems to be working great . Obviously I'm not running boost as high as before but so far from what I'm seeing, this setup is far and away the best I've ever tried. There appears to be no detrimental effect on engine cooling and IATs are staying within a few degrees of ambient AFTER a run! Need more testing but pretty confident this was a worthwhile upgrade.
OMP modification : Increased flow through the omp (see omp output thread for details) which I'm hoping will remove any need to premix at elevated boost on pump gas (not seeing this as a good idea with high ethanol content) . Too early to tell on this one.
This is making me so giddy ha! Are you planning on tearing down this stock block and rebuilding for more boost? Or wanting to test the limits of a stock block first?
I have a bunch of REW block parts I am getting ready to sell to rebuild a Renny and get a G30-660 for when this is released.
This really has the possibility to put the RX-8 back on the map competing with S2000, and 350z/370z as a builders car now knowing adding good power is an actual possibility. Engine swapping may soon not be such a considered option.
This is making me so giddy ha! Are you planning on tearing down this stock block and rebuilding for more boost? Or wanting to test the limits of a stock block first?
I have a bunch of REW block parts I am getting ready to sell to rebuild a Renny and get a G30-660 for when this is released.
This really has the possibility to put the RX-8 back on the map competing with S2000, and 350z/370z as a builders car now knowing adding good power is an actual possibility. Engine swapping may soon not be such a considered option.
In for more results
Glad you see it the same way I do .
So this current block is the one that came out of my blue N/A car. It wasn't really in the plan to fit it but I wanted to get this manifold tested and underway. I think it's not such a bad thing to try the manifold on a bone stock engine as that's what most people will do anyway. I don't plan to push it much further than this as I believe around 300whp is the safe limit for the stock block on pump gas both for detonation and longevity.
I'm currently getting another block built which is waiting on machine work being done to lower the CR of the rotors.
This new block will have :
9.4:1 rotors
RX7 apex seals
Dowel pining
Increased oil pressure
G30 - 660 with 0.83 AR housing
Currently the GTX3582 0.83 is spooling way better than I expected it to. Some of this may be due to the porting of the T04B compressor housing I did, but mostly I think it's the added heat retention and improved flow dynamics of the cast stainless manifold. .... I believe the G30-66 with the 0.83 will spool even quicker - MUCH quicker. Excited to see how that pans out.
Probably my biggest challenge will be actually doing the work ... this last install almost broke me !
I definitely will be watching EMAP !
But as a matter of interest the GTX3582 made over 400whp on a 0.83 and the emap on that was way higher than the G30-660 1.01 at similar power. I expect the G30-660 0.83 to actually outperform the GTX3582 0.83 in every way.
So this current block is the one that came out of my blue N/A car. It wasn't really in the plan to fit it but I wanted to get this manifold tested and underway. I think it's not such a bad thing to try the manifold on a bone stock engine as that's what most people will do anyway. I don't plan to push it much further than this as I believe around 300whp is the safe limit for the stock block on pump gas both for detonation and longevity. !
That's exactly what I would look for on my 8, Stock, 300hp, Sunday driver, can care less for records.
Great spool and power results for < 9psi. Not sure if any of us would have thought this would be achievable 5 years ago.
Here's a thought exercise: You mentioned above that you didn't want to push over 300whp. Is there such a thing as maximum safe WHP, or is the maximum safe value a PR, IMAP, EMAP or combination of some or all of these? We've already determined that IMAP(boost) isn't the only factor, and neither is WHP, because reducing EMAP or PR has shown that higher IMAP and WHP values can be achieved before the motor fails. So which of these, or which combination of these is most critical to determining the maximum potential of the motor before it's likely to fail?
Would be good to put together a table of values (e.g. WHP, PR, IMAP, EMAP) showing some maximum values that have been run safely. Hard to do unless you're using the same type of motor build and same type of gas for all results across the table. A formula or rule of thumb could be identified if there were enough data points.
Last edited by JimmyBlack; 07-29-2021 at 09:46 PM.
Great spool and power results for < 9psi. Not sure if any of us would have thought this would be achievable 5 years ago.
Here's a thought exercise: You mentioned above that you didn't want to push over 300whp. Is there such a thing as maximum safe WHP, or is the maximum safe value a PR, IMAP, EMAP or combination of some or all of these? We've already determined that IMAP(boost) isn't the only factor, and neither is WHP, because reducing EMAP or PR has shown that higher IMAP and WHP values can be achieved before the motor fails. So which of these, or which combination of these is most critical to determining the maximum potential of the motor before it's likely to fail?
Would be good to put together a table of values (e.g. WHP, PR, IMAP, EMAP) showing some maximum values that have been run safely. Hard to do unless you're using the same type of motor build and same type of gas for all results across the table. A formula or rule of thumb could be identified if there were enough data points.
Yeah , great point James .Good to see you still taking an interest !
I tried to list how I believe they stack up in order of importance below.
Something like you suggest above would be brilliant if it were practical to get the information.
As you can see .... I rate IAT as a more critical parameter than most and EMAP is lower down the list for me. I think EMAP (while important) isn't as critical as it is for other engines with overlap.
Another one we cant really measure is : Heat soak into the intake tract . I think this is something very much overlooked but also important.
Also : Just added emap to the above charts posted yesterday.
Brett, why don't you think EMAP is as important? I imagine depending on power levels it is more related to the temperature at the exhaust ports and potential side seal failure, is there a correlation between HP and EMAP where you should be looking at reducing EMAP to go higher on HP reliably?
I find this discussion super interesting as my car is mostly used on track, with fast long straights (suzuka) and reliability and HP are something i'm looking at the most.
Brett, why don't you think EMAP is as important? I imagine depending on power levels it is more related to the temperature at the exhaust ports and potential side seal failure, is there a correlation between HP and EMAP where you should be looking at reducing EMAP to go higher on HP reliably?
I find this discussion super interesting as my car is mostly used on track, with fast long straights (suzuka) and reliability and HP are something i'm looking at the most.
I do think it's important. All the things on that list are important ..... but what I've noticed with EMAP is that it doesn't have as much effect on power with the Renesis as it does with other engines. I would put this down to the lack of overlap and the limited carryover of exhaust gas between cycles.
If you compare say ... a Greddy setup to my setup ..... where the Greddy could have as much as double the emap ...then yes ...big difference. But comparing different AR turbine housings on the same setup ..... barely noticeable (apart from the spoolup difference).
That I understand, I was thinking more on the lines that to a certain power level, EMAP should be kept to a certain value or lower for engine longevity. Specially for us guys that track our cars and do many laps. EMAP seems to be more critical towards reliability than in piston engines.
I definitely will be watching EMAP !
But as a matter of interest the GTX3582 made over 400whp on a 0.83 and the emap on that was way higher than the G30-660 1.01 at similar power. I expect the G30-660 0.83 to actually outperform the GTX3582 0.83 in every way.
which is why you should also expect that the G25-660 0.92 is the choice for absolute best spool to power ratio once the MOI and other differences are considered, including the smaller fitment size.
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which is why you should also expect that the G25-660 0.92 is the choice for absolute best spool to power ratio once the MOI and other differences are considered, including the smaller fitment size.
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Maybe ... but moi isn't the only consideration . Turbine efficiency also comes into it and that can vary going from one turbine to another on the same compressor. Interesting to note that Garrett doesn't give a max. efficiency figure for the G25 turbine !
That I understand, I was thinking more on the lines that to a certain power level, EMAP should be kept to a certain value or lower for engine longevity. Specially for us guys that track our cars and do many laps. EMAP seems to be more critical towards reliability than in piston engines.
Prettty hard to put a number on it ... I wouldn't like to guess. But whatever it might be would vary relative to all the other possible problem parameters . The possibilities are infinite.
Maybe ... but moi isn't the only consideration . Turbine efficiency also comes into it and that can vary going from one turbine to another on the same compressor. Interesting to note that Garrett doesn't give a max. efficiency figure for the G25 turbine !
more so at high Pr, but it will have to be quite a bit to make up this much difference at the Pr ranges we’re discussing (difference between Blue (G30-0.83) and Black (G25-0.92) lines in middle of the overlay below)
which wrt MOI we’re talking about the mm diameter differences between 54i/49e for G25, 60i/55e for G30, 68i/62e for 3582 in heavy material down at low rpm, the difference will definitely be there coupled with the same mass flow moving through a smaller flow path (higher velocity)
more so at high Pr, but it will have to be quite a bit to make up this much difference at the Pr ranges we’re discussing (difference between Blue (G30-0.83) and Black (G25-0.92) lines in middle of the overlay below)
which wrt MOI we’re talking about the mm diameter differences between 54i/49e for G25, 60i/55e for G30, 68i/62e for 3582 in heavy material down at low rpm, the difference will definitely be there coupled with the same mass flow moving through a smaller flow path (higher velocity)
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Nice comparison. You are probably correct with your assessment ... certainly looks that way on paper. I do like the fact that the G30 has the 1.01 option though (for those that want to track their cars) and that it's now a known quantity.
Pic showing close up of IC install ..... this seems to be working exceptionally well so far but it hasn't seen any hot (25C plus ) days yet.
IAT post IC at cruise : 1-2 deg C over ambient
IAT after 9psi log in 3rd : 6-7 degrees over ambient
Engine coolant temps at cruise (cool day 15C) : low 80s
Engine coolant temps after 3rd gear pull ...go up by 1-2 degrees C only
Note : the inlet hose does block the left hand side air to the radiator but the right hand side is unobstructed. I think this will be enough even on hot days on track but still to get that test.
07-28-2021, 12:54 AM
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