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Hi, this is a very interesting looking manifold. Are any out there running and is it available commercially to purchase yet?
There are quite a few out there already but sadly only 3 actually running so far. One in Aussie , one in UK and my one in NZ.
There are a couple more in US getting close but these things take time.
PM me if interested- there is a waiting list so don't expect anything soon.
If that theory holds truth, then measuring anywhere in the blue segment marked with a **? is pointless, since there's hardly any flow going on there. The measurement point should be changed to 2 locations, simultaneously, in the purple areas with 5* and a ?. I also understand this is much easier said than done. But it may reveal that rotors don't run the same EMAP.
Actually the most accurate point to measure pressure is where it is "stagnant", in the blue area you noted. You have to assume that the pressure in the exhaust manifold is ~ equal. Flow will be directed to where it is lower. This ~ is less than 0.1 bar difference. Diference is more from acoustic pulses of the pressure in the manifold than actual difference.
I'm writing this as someone with 10+ years in fluid dynamics and engineering research / Master of science....
acknowledging the pressure always equalizes and flow is a consequence of pressure, the pressure before the collector of WG and downpipe has to be same, and flow numbers can be different, which than implies that pressure differential across WG is same as it is on the Turbine, which implies that the inlet to the turbine and WG are the same, meaning that the pressure in the manifold is equal. again measured difference in the manifold will be acoustic pressure waves reflecting from the body of the manifold.
I do my tuning from boost control first to ignition last. I play with my EBC to get 10 psi across the rev range; until I dial that I set an extremely rich AFR and with 8 deg. of timing. Emap was over 30psi. Still, under these conditions an overboost won't kill my engine.
you have to remember that a richer mixture will make you flow more volume of air through the exhaust, as well as later ignition as the EGT will be higher, meaning that the exhaust will have to flow significantly more volume, raising EMAP
you have to remember that a richer mixture will make you flow more volume of air through the exhaust, as well as later ignition as the EGT will be higher, meaning that the exhaust will have to flow significantly more volume, raising EMAP
If he was flowing say 400g/s of air we can calculate the difference in massflow between say 11.5: 1 and 10:1 (lower than 10:1 and it wouldn't run).
At 10:1 air/fuel the fuel flow is 400x 0.1 = 40g/s
At 11.5 :1 air/fuel the fuel flow is 400x 0.115 = 46g/s
So the difference in mass flow is 6g/s ...or 6/400x100 = 1.5% more massflow
That alone would not make a lot of difference to emap .... but combined with the timing changes
If he was flowing say 400g/s of air we can calculate the difference in massflow between say 11.5: 1 and 10:1 (lower than 10:1 and it wouldn't run).
At 10:1 air/fuel the fuel flow is 400x 0.1 = 40g/s
At 11.5 :1 air/fuel the fuel flow is 400x 0.115 = 46g/s
So the difference in mass flow is 6g/s ...or 6/400x100 = 1.5% more massflow
That alone would not make a lot of difference to emap .... but combined with the timing changes
Maybe I'm missing something, but wouldn't a higher air/fuel ratio result in lower fuel flow? So that 11.5:1 ratio should really be 400 / 11.5 = 34.8 g/s
Maybe I'm missing something, but wouldn't a higher air/fuel ratio result in lower fuel flow? So that 11.5:1 ratio should really be 400 / 11.5 = 34.8 g/s
Quite right .. doesn't change anything much.......... but yes!
^^ let me correct you both; it depends on the fuel being used because obviously the difference between straight gasoline and E85 is not going to be a simple ratio as you did there. Most people don’t even recognize that stoichiometric for E10 pump gas is 14.1, not 14.7. Whereas stoich for E100 is 9.0. The reason being that ethanol is a highly oxygenated fuel. Which the calculations above don’t account for. And also why there’s more to the “E30 gets most of the benefit” fake news schtick for those who understand how to extract all of the performance benefit that a higher ethanol content has to offer.
Came here to post something else though, so will do that separate to avoid the inevitable argument likely to ensue from this one …
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thought you might be interested in a recent result comparing the Pulsar version of the Garrett G30-700 against the GT3582 on an FC 13B RX7
the numbers on the surface don’t seem impressive, but this particular dyno seems to typically indicate 10 - 15% less output compared to others. Of course what we don’t have is a direct comparison between the Pulsar semi-copycat and the true Garrett G30-770:
^^ let me correct you both; it depends on the fuel being used because obviously the difference between straight gasoline and E85 is not going to be a simple ratio as you did there. Most people don’t even recognize that stoichiometric for E10 pump gas is 14.1, not 14.7. Whereas stoich for E100 is 9.0. The reason being that ethanol is a highly oxygenated fuel. Which the calculations above don’t account for. And also why there’s more to the “E30 gets most of the benefit” fake news schtick for those who understand how to extract all of the performance benefit that a higher ethanol content has to offer.
Came here to post something else though, so will do that separate to avoid the inevitable argument likely to ensue from this one …
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Who said anything about ethanol ? You are commenting in the wrong thread.
thought you might be interested in a recent result comparing the Pulsar version of the Garrett G30-700 against the GT3582 on an FC 13B RX7
Agree that the numbers are down due possibly to the dyno itself. But that 3582 result is just terrible ... low reading dyno or not. Maybe it was a china 3582 from back when they were producing crap?
Also , and this is just a guess, it looks like the 3582 didn't spool up till 5000rpm .... ish. We know those turbos do much better than that!
Who said anything about ethanol ? You are commenting in the wrong thread.
admittedly I don’t know if the fuel you’re using there in NZ has any ethanol or not (Gull Force 10 or straight 98), but the other person is in the USA and very few places here have straight gasoline available. So the point is that if the fuel has ethanol, oxygenated gasoline, or any additional liquid oxygen source then the formula/calcs above aren’t accurate. I then attempted to clarify why that is. Because the more oxygen supplied through the fuel, the more fuel needed to compensate for that addition. That’s why pure ethanol stoich is 9.0. Up in the E70+ range, then 30% and higher of the fuel weight is oxygen. Methanol is even higher (~6.5 stoich). That’s how they both make power over gasoline. lIt’s not just about octane and knock resistance.
So you’re right that this isn’t an ethanol thread, but I didn’t bring it up for that reason, only to point out how people will err using the formulas the way it was done above. Because even air itself is mostly nitrogen and only ~21% oxygen. Once you start adding oxygen through the fuel, the calculation results as done above are inaccurate. Not to mention some other errors the engineering expert is spreading around. Which as a fluid dynamics specialist I’m sure he can appreciate how running high levels of ethanol in a very high power engine can even influence dynamic compression ratio to the point of altering optimum ignition timing. Liquid being incompressible and so much going in that ot can’t just immediately vaporize into a compressible gas.
stuff most enthusiasts neither consider nor know of.
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Something very weird happened on the way back from Auckland yesterday. There had been a police chase on the expressway ending in a car partially blocking the road. The result was I was stuck in traffic moving at a crawl for around 3/4hr on a Hot day (26C). Was crawling along at around 5km/hr which was below the speed I could idle at so was having to slip the clutch to maintain constant speed. All of a sudden the engine just stopped for no apparent reason. Was lucky that I had some momentum and was able to roll off to the side of the road. I waited around 30 seconds then tried starting it. It fired back up immediately and I headed on my way feeling puzzled.
This has never happened before so I was thinking about what may have caused it. Obviously the length of time spent crawling along at idle had something to do with it. My best guess is that : : my turbo intake tube got very hot (it passes close to the exhaust manifold) and the intercooler plus charge pipes were completely heat soaked. This may have lead to extreme IATs ... maybe over 100C, and the ECU has shut the engine down as a protection measure somehow.
So , I'm thinking that ,at the very least, I should fit a protective sleeve over the intake as it passes by the manifold. This is a heads up for those living in hot climates that could potentially end up in traffic jams.
Something very weird happened on the way back from Auckland yesterday. There had been a police chase on the expressway ending in a car partially blocking the road. The result was I was stuck in traffic moving at a crawl for around 3/4hr on a Hot day (26C). Was crawling along at around 5km/hr which was below the speed I could idle at so was having to slip the clutch to maintain constant speed. All of a sudden the engine just stopped for no apparent reason. Was lucky that I had some momentum and was able to roll off to the side of the road. I waited around 30 seconds then tried starting it. It fired back up immediately and I headed on my way feeling puzzled.
This has never happened before so I was thinking about what may have caused it. Obviously the length of time spent crawling along at idle had something to do with it. My best guess is that : : my turbo intake tube got very hot (it passes close to the exhaust manifold) and the intercooler plus charge pipes were completely heat soaked. This may have lead to extreme IATs ... maybe over 100C, and the ECU has shut the engine down as a protection measure somehow.
So , I'm thinking that ,at the very least, I should fit a protective sleeve over the intake as it passes by the manifold. This is a heads up for those living in hot climates that could potentially end up in traffic jams.
26C is a hot day? Hoo boy. Might have to get extra creative with a cooling solution in my climate, 40C is around the average in the summer time.
... : my turbo intake tube got very hot (it passes close to the exhaust manifold) and the intercooler plus charge pipes were completely heat soaked. This may have lead to extreme IATs ... maybe over 100C, a....
An intake pipe temperature (even 400C, which I doubt as it still has fresh air flowing through it) will not heat the intake charge beyond few degC, not 70 over ambient, especially to heat soak the IC at the same time. The energy there is very minimal. (please take this as is as I have lot of thermal analysis and design under my belt as an ing).
to "visualize it" think of it like following:
the intake pipe has very low area/volume ratio compared to the IC to heat up the intake air. The intake is heated only with radiation (as if it was convection than your shoes would be melting), the FMIC has huge area to take of the heat of of the intake charge (at least 100x larger surface), and also has a huge area to dissipate that heat by convection (fluid circulation) with equally large area to dissipate the heat.
An intake pipe temperature (even 400C, which I doubt as it still has fresh air flowing through it) will not heat the intake charge beyond few degC, not 70 over ambient, especially to heat soak the IC at the same time. The energy there is very minimal. (please take this as is as I have lot of thermal analysis and design under my belt as an ing).
to "visualize it" think of it like following:
the intake pipe has very low area/volume ratio compared to the IC to heat up the intake air. The intake is heated only with radiation (as if it was convection than your shoes would be melting), the FMIC has huge area to take of the heat of of the intake charge (at least 100x larger surface), and also has a huge area to dissipate that heat by convection (fluid circulation) with equally large area to dissipate the heat.
hmmmmm , my observations suggest IATs can go pretty high at low flow. I think I might need do some testing.
26C is a hot day? Hoo boy. Might have to get extra creative with a cooling solution in my climate, 40C is around the average in the summer time.
hehe - wondered if I would get a hard time over that.....As Milos pointed out, a 15C difference in ambient isn't such a big issue so long as the engine isn't overheating as well. I'm more concerned with the heat off the manifold and the hot air blown onto the pipes by the fans.
Sorry, I don't believe that high IATs triggered the cut, or the ecu caused a cut due to high IATs.
My intake pipe is similarly close to the turbo manifold. I've been crawling in 36-37C heat for at least 30 minutes, in a black car, with AC on full blast, fans on full blast and I have all the pipework in the engine bay. My IAT is placed before the thr. body and it sat at 65C, while oil and coolant were at 84C. In the summer after restarting a hot engine that was parked for 10-20 mins I'd get a IAT reading of 70C and yet, no issues.
it would be easy enough to replicate and see what happens with a false IAT signal
but given how Mazda typically has handled similar situations, my expectation would be for it to go into limp mode rather that shutdown completely, it’s just an opinion though.
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it would be easy enough to replicate and see what happens with a false IAT signal
but given how Mazda typically has handled similar situations, my expectation would be for it to go into limp mode rather that shutdown completely, it’s just an opinion though.
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Ah , you reminded me that I've already been down that path: https://www.rx8club.com/series-i-eng...3/#post4716319
In that case I couldn't reflash the ecu after setting a false ECT (140C) and had to disconnect the sensor to remedy the situation.
Ciprian : can you use the data in that thread to find the tables that pull timing? NVM ...just saw that you have already done that on page 2 of that thread.
So ...if it wasn't the ecu doing it ............what did happen?
I remember feeling the engine dying and quickly putting foot on clutch and trying to keep it going with the throttle. It kinda half pie responded by revving up slightly but then died completely.
Maybe it was a fuel issue ..... I do run the DW300 pump - that may have overheated.
Fuel level was at just below 3/4 tank so I can't see the fuel itself getting that hot.
So ...if it wasn't the ecu doing it ............what did happen?
I remember feeling the engine dying and quickly putting foot on clutch and trying to keep it going with the throttle. It kinda half pie responded by revving up slightly but then died completely.
Maybe it was a fuel issue ..... I do run the DW300 pump - that may have overheated.
Fuel level was at just below 3/4 tank so I can't see the fuel itself getting that hot.
Were you sitting stationary when it happened or in motion? I just bring that up because if you were crawling along for 3-4 hours and constantly slipping the clutch, I know my left foot would be getting tired, could it possibly have been stalled due to a bad start when you were leaving from a stop? Yeah it sounds silly, but sitting for that long in traffic doing the same motions over and over can kind of distort a person's perception of what actually happened when it stalled.
08-14-2023, 09:56 PM
