Author Topic: Stock Port, Sequential Twins @ c.1.03 Bar - 398 BHP / 360 lb. ft.  (Read 1503 times)

Offline cib24

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Had my car dyno'd today using a Maha dyno. Not 100% sure about the results as they seem kind of high to me by about 40-50 bhp but I'm not complaining! The curve is pretty good and the torque curve can't really be improved without more fuel and more boost on the primary.

AFRs at the low end start around 11.4:1 after about 3,000 RPM average about 10.9-11.1:1 to redline.

Air temps on water were low 30's C, off water as you see in the Commander shot.

Stock fuel system. Stock 550/850 cc/min injectors, stock pump hotwired for full 12V, HKS Twin Power and mods in signature.

Ambient temps were about 8 C today. Pretty cold.

398 Bhp (340 Whp) @ 6,036 RPM, 350-360 lb/ft (299-307 Wlb/ft) @ 3,000 - 6,000 RPM.


Video of the dyno and my disbelief

<a href="http://www.youtube.com/watch?v=y6LIGkys5AY" target="_blank">http://www.youtube.com/watch?v=y6LIGkys5AY</a>



1999 Mazda RX-7 Type RS

Mods - Twins @ 1.03 bar, Full 80mm (3") exhaust, Greddy SMIC, Stock Airbox, AEM WI, HKS TwinPower, Koyo N-Flow, Ohlins, Poly Bushes

12 Nov 17
398 Bhp (340 Whp) @ 6,036 RPM
350-360 lb/ft (299-307 Wlb/ft) @ 2,900 - 6,100 RPM

Offline re japi

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Re: Stock Port, Sequential Twins @ c.1.03 Bar - 398 BHP / 360 lb. ft.
« Reply #1 on: November 13, 2017, 06:34:48 AM »
Really nice result!  :13:
I thought that stock REW cant do that kind of power...
Power is nothing without control. Weight is enemy of performance, handling and braking.

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Offline Essex2Visuvesi

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Re: Stock Port, Sequential Twins @ c.1.03 Bar - 398 BHP / 360 lb. ft.
« Reply #2 on: November 13, 2017, 11:54:58 AM »
95% injector duty is pushing the limits of your current injectors. Might be wise to get some bigger injectors

Offline cib24

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Re: Stock Port, Sequential Twins @ c.1.03 Bar - 398 BHP / 360 lb. ft.
« Reply #3 on: November 13, 2017, 12:16:18 PM »
Maybe, but a few things about that:

  • In cold weather like yesterday the duty was 95%, normally it's in the low 90s.
  • The injector duty spikes to 95% only around the transition point as it is the most critical and dangerous part of the map. 3,500-5,000 RPM to ensure there is enough fuel there at all times. Everywhere else in the map it's closer to 90%.
[li]I asked several tuners in the UK (Hayward, WGT, Rotor Torque) before deciding to push for over 1.0 bar on the stock fuel system, and every single one said that they have never seen injectors fail or get stuck open even at 100%.
[/li][/list]

Now, that's not to say I shouldn't have a little more headroom but then I'm not 100% sure that even matters. I don't think the Power FC is smart enough to recognise an underperforming injector or low fuel pressure and supplement those types of issues to inject even more fuel. It just reads from pre-loaded fuel tables with temp correction factors to inject more or less fuel depending on intake air temps. So, if an ancillary like a fuel injector fails it is going to pop anyway.

But please tell me if I'm wrong?

In any case, I won't be boosting much in the cold weather as I won't be driving it when the salt arrives so I should be okay. If not, well it's my fault then but I would rather run just under 1.0 bar than swap out my secondary fuel rail and make all of those mods for overkill 1650s.
1999 Mazda RX-7 Type RS

Mods - Twins @ 1.03 bar, Full 80mm (3") exhaust, Greddy SMIC, Stock Airbox, AEM WI, HKS TwinPower, Koyo N-Flow, Ohlins, Poly Bushes

12 Nov 17
398 Bhp (340 Whp) @ 6,036 RPM
350-360 lb/ft (299-307 Wlb/ft) @ 2,900 - 6,100 RPM

Offline boosted

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Re: Stock Port, Sequential Twins @ c.1.03 Bar - 398 BHP / 360 lb. ft.
« Reply #4 on: November 13, 2017, 03:21:45 PM »
Nearly 15 psi...when i swapped turbos mine was running 15 to 16psi at the top end of the rpm...its been mapped at this but i subsequently tuned down to 13.5 14psi with an orifice plate in the end of the downpipe...its defo got less power with 1.5psi cut...i thought 400bhp was poss with 16psi tune so your not far off...
How long the turbos last though is debatable...not talking seals but wastgate cracking up with the heat....and in ability to flow through wastegate and boost creep and knock...thats what concerned me but i dont have water injection.
I just had rotary paranoia with it when taking to track so cut it back abit.


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92 FD rx7 Twins 13.5psi. Track car
94 Westfield Se 231 rx8 street port powered. Race car
EAT SLEEP ROTOR REPEAT.

Offline cib24

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Re: Stock Port, Sequential Twins @ c.1.03 Bar - 398 BHP / 360 lb. ft.
« Reply #5 on: November 13, 2017, 03:56:46 PM »
Yeah, that's exactly why I added water. If I was going to try to run c.15 PSI without a huge V Mount then I wanted water to keep things cool. jdmr_neil ran 1.2 bar (17.5 PSI) for over 4 years doing mostly track days with the car and running 500cc/min of water before his twins started to smoke slightly.

Right now I'm using a set of early spec twins and saving my 99s for later so I don't mind potentially cooking the early spec ones that much. When I put the 99s back in the car boost will be turned down to 0.85-0.9 bar as they are too valuable to push too hard.
1999 Mazda RX-7 Type RS

Mods - Twins @ 1.03 bar, Full 80mm (3") exhaust, Greddy SMIC, Stock Airbox, AEM WI, HKS TwinPower, Koyo N-Flow, Ohlins, Poly Bushes

12 Nov 17
398 Bhp (340 Whp) @ 6,036 RPM
350-360 lb/ft (299-307 Wlb/ft) @ 2,900 - 6,100 RPM

Offline neil_jdmr

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Re: Stock Port, Sequential Twins @ c.1.03 Bar - 398 BHP / 360 lb. ft.
« Reply #6 on: November 13, 2017, 04:49:35 PM »
Yep and tbh i could have easy kept tracking mine as they were still boosting perfect and only a little smoke on overrun. I also had a standard fuel system worth exception to a bosch fuel pump and the base pressure was slightly increased.

Im really pleased with your bhp figure. I always felt my car was around the 400bhp mark judging by the cars i was sitting on the bumper of on the long straight at croft. It would be nice to see some kind of industry standard with dynometer systems and operation so it gets rid of such a variance in results i saw.

All in all, great results on a lovely car.
Standard sequential, standard engine, Oem body, 1.2bar, WI

Twins retired. KKK K27 1.25bar courtesy of Jason and Stu

Offline boosted

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Re: Stock Port, Sequential Twins @ c.1.03 Bar - 398 BHP / 360 lb. ft.
« Reply #7 on: November 13, 2017, 04:51:39 PM »
Mmmm i need water...i miss that extra 1.5 psi lol! Got used to what i got...

Sent from my SM-N910F using Tapatalk

92 FD rx7 Twins 13.5psi. Track car
94 Westfield Se 231 rx8 street port powered. Race car
EAT SLEEP ROTOR REPEAT.

Offline boosted

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Re: Stock Port, Sequential Twins @ c.1.03 Bar - 398 BHP / 360 lb. ft.
« Reply #8 on: November 13, 2017, 05:00:57 PM »
Was you wastegate ported Neil?

Sent from my SM-N910F using Tapatalk

92 FD rx7 Twins 13.5psi. Track car
94 Westfield Se 231 rx8 street port powered. Race car
EAT SLEEP ROTOR REPEAT.

Offline re japi

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Re: Stock Port, Sequential Twins @ c.1.03 Bar - 398 BHP / 360 lb. ft.
« Reply #9 on: November 13, 2017, 05:13:04 PM »


It would be nice to see some kind of industry standard with dynometer systems and operation so it gets rid of such a variance in results i saw.

Exactly. I dont understand why there is so much difference between dynos...



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Power is nothing without control. Weight is enemy of performance, handling and braking.

http://s1293.photobucket.com/user/japi_laukkanen/library/Japi?sort=3&page=1

Offline neil_jdmr

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Re: Stock Port, Sequential Twins @ c.1.03 Bar - 398 BHP / 360 lb. ft.
« Reply #10 on: November 13, 2017, 05:22:58 PM »


It would be nice to see some kind of industry standard with dynometer systems and operation so it gets rid of such a variance in results i saw.

Exactly. I dont understand why there is so much difference between dynos...



Lähetetty minun E2303 laitteesta Tapatalkilla

I had almost 80bhp difference from 1 dyno to another with another reading just north of the middle.

No Jon everything was standard turbo wise
Standard sequential, standard engine, Oem body, 1.2bar, WI

Twins retired. KKK K27 1.25bar courtesy of Jason and Stu

Offline neil_jdmr

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Re: Stock Port, Sequential Twins @ c.1.03 Bar - 398 BHP / 360 lb. ft.
« Reply #11 on: November 13, 2017, 05:24:25 PM »
Iirc it was 409bhp, 386bhp and 327bhp all on the same car within a year???
Standard sequential, standard engine, Oem body, 1.2bar, WI

Twins retired. KKK K27 1.25bar courtesy of Jason and Stu

Offline re japi

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Re: Stock Port, Sequential Twins @ c.1.03 Bar - 398 BHP / 360 lb. ft.
« Reply #12 on: November 13, 2017, 05:30:00 PM »
Iirc it was 409bhp, 386bhp and 327bhp all on the same car within a year???
Well, thats a really big difference.  Usually its about 30-40 horses in 300-400 power range...

Offcourse weather,  circumstances and so on has some effect, but not 80 horses...

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Power is nothing without control. Weight is enemy of performance, handling and braking.

http://s1293.photobucket.com/user/japi_laukkanen/library/Japi?sort=3&page=1

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Re: Stock Port, Sequential Twins @ c.1.03 Bar - 398 BHP / 360 lb. ft.
« Reply #13 on: November 13, 2017, 05:34:56 PM »
Ive no idea what mines running at circa 320 bhp est now at 13.5 psi..based on some previous owner dyno runs...original tubbys had a blow on flange so replacing them and adding a twinpower..took me 2 15/16psi. Its tuned by Carl at that but i followed his advice and fitted the orifice plate in the exhaust to control the creep..
Seems every car gonna behave different bit like the dynos lol!.

Sent from my SM-N910F using Tapatalk

92 FD rx7 Twins 13.5psi. Track car
94 Westfield Se 231 rx8 street port powered. Race car
EAT SLEEP ROTOR REPEAT.

Offline re japi

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Re: Stock Port, Sequential Twins @ c.1.03 Bar - 398 BHP / 360 lb. ft.
« Reply #14 on: November 13, 2017, 05:50:39 PM »
Ive no idea what mines running at circa 320 bhp est now at 13.5 psi..based on some previous owner dyno runs...original tubbys had a blow on flange so replacing them and adding a twinpower..took me 2 15/16psi. Its tuned by Carl at that but i followed his advice and fitted the orifice plate in the exhaust to control the creep..
Seems every car gonna behave different bit like the dynos lol!.

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What I have heard/read, pre 99 models usually have that about 320 with 1-1,1bar boost. Some have gone up to 350 range...

 Dunno much about 99 models, but I think they have better turbos(about 15% better flow) and better ecu than pre 99 models...

But yes, usually I suspect that dynos is not accurate...

Lähetetty minun E2303 laitteesta Tapatalkilla

Power is nothing without control. Weight is enemy of performance, handling and braking.

http://s1293.photobucket.com/user/japi_laukkanen/library/Japi?sort=3&page=1