255 HP --> 280 BHP... How?
06-04-20, 12:24 PM
#1
Recovering Miataholic
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255 HP --> 280 BHP... How?
Mazda's advertised brake horsepower for the 13B-REW engine went from 255 to 280 some time after the cars were no longer available in the U.S. Was that entirely due to the re-spec'd 1999 turbochargers, or were there other mods that contributed to the higher figure? Does anyone know?
06-04-20, 12:49 PM
#3
If you dig into that article, it basically says that Mazda offered 255hp and 280hp cars at the same time, and the only hardware difference was the turbos and oil metering system. So it's mostly the turbos and an associated change in stock ECU tuning. The turbine has less backpressure and the compressor has more efficiency.
They do go into differences in the air intake system which are supposed to add 10hp (and yet apply to both 255hp models and 280hp models). But that wasn't explained well in context. Engine dyno horsepower runs for advertised power don't really reflect that kind of change, as they are done in open-air dyno cells with supply air at fixed temperatures. The only way that's reflected in the 280hp number is if they force-cooled the intercooler more in the test cell during the rating run, or if they applied some kind of correction factor. There's very little transparancy as to how advertised horsepower is generated for those that do not do official SAE certification, especially back then. Both Mazda (Rx-8) and Ford (Mustang Cobra) had to lower advertised power claims later.
They do go into differences in the air intake system which are supposed to add 10hp (and yet apply to both 255hp models and 280hp models). But that wasn't explained well in context. Engine dyno horsepower runs for advertised power don't really reflect that kind of change, as they are done in open-air dyno cells with supply air at fixed temperatures. The only way that's reflected in the 280hp number is if they force-cooled the intercooler more in the test cell during the rating run, or if they applied some kind of correction factor. There's very little transparancy as to how advertised horsepower is generated for those that do not do official SAE certification, especially back then. Both Mazda (Rx-8) and Ford (Mustang Cobra) had to lower advertised power claims later.
06-04-20, 01:17 PM
#4
Rotor or no motor
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If you dig into that article, it basically says that Mazda offered 255hp and 280hp cars at the same time, and the only hardware difference was the turbos and oil metering system. So it's mostly the turbos and an associated change in stock ECU tuning. The turbine has less backpressure and the compressor has more efficiency.
They do go into differences in the air intake system which are supposed to add 10hp (and yet apply to both 255hp models and 280hp models). But that wasn't explained well in context. Engine dyno horsepower runs for advertised power don't really reflect that kind of change, as they are done in open-air dyno cells with supply air at fixed temperatures. The only way that's reflected in the 280hp number is if they force-cooled the intercooler more in the test cell during the rating run, or if they applied some kind of correction factor. There's very little transparancy as to how advertised horsepower is generated for those that do not do official SAE certification, especially back then. Both Mazda (Rx-8) and Ford (Mustang Cobra) had to lower advertised power claims later.
They do go into differences in the air intake system which are supposed to add 10hp (and yet apply to both 255hp models and 280hp models). But that wasn't explained well in context. Engine dyno horsepower runs for advertised power don't really reflect that kind of change, as they are done in open-air dyno cells with supply air at fixed temperatures. The only way that's reflected in the 280hp number is if they force-cooled the intercooler more in the test cell during the rating run, or if they applied some kind of correction factor. There's very little transparancy as to how advertised horsepower is generated for those that do not do official SAE certification, especially back then. Both Mazda (Rx-8) and Ford (Mustang Cobra) had to lower advertised power claims later.
the manual version of the RB aka RB-S is 265ps
the turbos are identical from the 265ps to the 280ps model.(and obviously the 255ps automatic ones)
it makes zero sense to have different turbos for 15ps... the difference is most definitely in the tune as they come with different ecus N3G1 vs N3G2 and N3G3 and whatever else comes in the 99spec ones.
also, the 96+ models were also the same way (280ps vs 265ps and 255ps for the automatics) with N3F1 turbos and the similar variation in the ECU part number variation
Last edited by R-R-Rx7; 06-04-20 at 02:34 PM.
06-04-20, 03:14 PM
#6
RX-7 Bad Ass
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I do believe some of the increase was in the ECU and it running slightly more boost than stock.
At the stock power level it takes VERY little to bump power up 30hp or so. There's a LOT of headroom for modification on a stock car.
The 99 "low power" cars were 265hp, they did get a little bump from some of the other minor changes - I think the stock downpipe was a little bigger diameter, IC pipes were revised, etc.
Dale
At the stock power level it takes VERY little to bump power up 30hp or so. There's a LOT of headroom for modification on a stock car.
The 99 "low power" cars were 265hp, they did get a little bump from some of the other minor changes - I think the stock downpipe was a little bigger diameter, IC pipes were revised, etc.
Dale
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R-R-Rx7 (06-04-20)
06-04-20, 03:51 PM
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just to clarify the oil metering was changed for all of the 99+ cars, not just the 280ps
they do indeed have different turbos, the 255/265ps turbos are the same ones we got here, the 280ps turbos are different, abradable seals, and different wheels. the 255/265 turbos (n3c1) have a snap ring to hold on the compressor covers, the 280ps (n3g1) is bolted
the ECU's are different as well, the 99+ cars get a speed bump (16bit?) and the 255/265/280ps cars all get different ecu's, in a modern car it would be a different flash
the 280ps cars run a little more boost
the ECU's are different as well, the 99+ cars get a speed bump (16bit?) and the 255/265/280ps cars all get different ecu's, in a modern car it would be a different flash
the 280ps cars run a little more boost
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06-04-20, 04:05 PM
#8
Rotary Freak
Originally Posted by j9fd3s
the 280ps cars run a little more boost
06-04-20, 04:35 PM
#9
Recovering Miataholic
Thread Starter
Thanks everyone! I didn't expect such a good response so quickly. Our car has never been on a dyno (ignoring smog testing), so I had no way of knowing whether its new engine with the '99 spec turbos would match the 280 hp later-model cars. I suppose the Bonez downpipe replacing the pre-cat would help a little, but since our ECU is essentially a 1994 U.S. model, there wouldn't be any help from that. But the engine runs very smoothly and pulls well... not complaining, just wondering.
Thanks again for the responses!
Thanks again for the responses!
06-05-20, 08:44 AM
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my friend bought an FD with the complete 280ps spec engine/turbos/trans in it, and we used the factory 280ps ecu, and it is a really good combination, the turbos respond quicker (full boost sooner, better throttle response) and it made power (it feels like DP,CB ECU)
the 99+ ecu also was cleaner on the smog dyno, except for the transitions it was as clean as an Rx8, so single digit numbers across the board.
the 99+ ecu also was cleaner on the smog dyno, except for the transitions it was as clean as an Rx8, so single digit numbers across the board.
06-05-20, 08:54 AM
#12
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just to clarify the oil metering was changed for all of the 99+ cars, not just the 280ps
they do indeed have different turbos, the 255/265ps turbos are the same ones we got here, the 280ps turbos are different, abradable seals, and different wheels. the 255/265 turbos (n3c1) have a snap ring to hold on the compressor covers, the 280ps (n3g1) is bolted
the ECU's are different as well, the 99+ cars get a speed bump (16bit?) and the 255/265/280ps cars all get different ecu's, in a modern car it would be a different flash
the 280ps cars run a little more boost
they do indeed have different turbos, the 255/265ps turbos are the same ones we got here, the 280ps turbos are different, abradable seals, and different wheels. the 255/265 turbos (n3c1) have a snap ring to hold on the compressor covers, the 280ps (n3g1) is bolted
the ECU's are different as well, the 99+ cars get a speed bump (16bit?) and the 255/265/280ps cars all get different ecu's, in a modern car it would be a different flash
the 280ps cars run a little more boost
i currently have an 01 RB-S (265ps) and the N3G1 turbos were the same as my 02 Type R (280ps) and other 01 and 02 models i have had over the years. the difference between the models of the same year, in terms of performance, is basically the ecu
between the US models vs JDM models. as Dale very correctly stated, the jdm downpipes dont have a cat there.
06-05-20, 09:27 AM
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R-R-Rx7 (06-05-20)
06-05-20, 11:23 AM
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06-07-20, 11:38 AM
#17
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06-07-20, 02:48 PM
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short answer, no, they have different plugs.
long answer is that the hardware on the car is all the same, so you could make some kind of adaptor and run it. in reality the Power FC gets you to almost the same place, and it plugs in
long answer is that the hardware on the car is all the same, so you could make some kind of adaptor and run it. in reality the Power FC gets you to almost the same place, and it plugs in
06-07-20, 05:18 PM
#19
Recovering Miataholic
Thread Starter
Thanks for that answer. I've been under the impression that the Power FC does not implement the Diagnostic Connector signals. Is that true?
06-08-20, 08:17 AM
#20
RX-7 Bad Ass
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The PFC doesn't do the check engine light/blink codes like the stock ECU, but you have the Commander with the sensor check screen which is way handier.
I don't know about, say, the old Mazda DTS-1000 tool working with the PFC but those are long gone and no one ever uses them anyhow.
People have kicked around putting the later harness/ECU/black box into a 93-95 car but it's just a lot of work and you can just do a PFC and simplified sequential and be ahead of the curve.
Dale
I don't know about, say, the old Mazda DTS-1000 tool working with the PFC but those are long gone and no one ever uses them anyhow.
People have kicked around putting the later harness/ECU/black box into a 93-95 car but it's just a lot of work and you can just do a PFC and simplified sequential and be ahead of the curve.
Dale
06-08-20, 09:06 AM
#21
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there are a lot of little differences that make it so that you pretty much need everything on the engine, you need the magic box, coil bracket, harness, intake manifolds, and probably some other stuff.
06-08-20, 01:25 PM
#22
Different car is running a pfc with some gremlins and the S7 setup was way better.
The headache was getting the usdm dash harness to play nice with the jdm ecu and harness. It was a while ago, so exact details are a bit hazy.
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