Stock baseline dyno
12-27-17, 01:20 PM
#16
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iTrader: (2)
Just FYI - I got a 29HP gain from my PPE headers and catalytic converters on the stock exhaust. I don't have the exact exhaust numbers, but compared to the headers there was only a slight bump in HP. This was adding exhaust after the headers though, so not really comparable to what you are talking about since I did not have a modified exhaust without upgraded headers. Considering how flattened the stock exhaust is, I was surprised there wasn't a more substantial increase. There was also minimal difference when keeping the valve open versus closed - primarily a sound difference.
I have spent a lot of time looking down ports and trying to figure out how things flow better. It is FAR from intuitive, and impossible to even guess without data. Some things look like they'd be horrible, but you put them on the flowbench, and they're actually pretty good. Other things look like they're perfect, but flow like total crap. Visual inspection is a poor measure of flow.
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Mingofish (12-28-17)
12-28-17, 04:59 AM
#17
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Corrected for truth. Many IS F owners still argue over the merits of gutting the OEM headers vs. aftermarket headers, and those who have run them head to head say there is very little difference.
I have spent a lot of time looking down ports and trying to figure out how things flow better. It is FAR from intuitive, and impossible to even guess without data. Some things look like they'd be horrible, but you put them on the flowbench, and they're actually pretty good. Other things look like they're perfect, but flow like total crap. Visual inspection is a poor measure of flow.
I have spent a lot of time looking down ports and trying to figure out how things flow better. It is FAR from intuitive, and impossible to even guess without data. Some things look like they'd be horrible, but you put them on the flowbench, and they're actually pretty good. Other things look like they're perfect, but flow like total crap. Visual inspection is a poor measure of flow.
(1) On an ISF with our ECU TUNE, headers only make about 5hp on average over gutted stock manifolds. It was only when we designed a new intake and tuned for it that we saw header gains of more like 15hp over gutted manifolds.
(2) RCF benefits more from headers than ISF, probably because the improved intake side, (larger maf housing, throttlebody, heads/valves, and cams). Gutted stock manifolds make about +10hp, versus about 25hp for headers.
Rafi
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Last edited by RRRacing; 12-29-17 at 05:31 AM.
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Mingofish (12-28-17)
01-04-18, 09:42 AM
#18
Might be dyno variation, but the LC500 dyno'ed at 390 whp (rated at 471 HP and 398 ft-lbs). If your 402 whp are SAE corrected then 17% typical mininum RWD drivetrain loss will yield a ~ 485 HP crank power.
https://www.youtube.com/watch?v=hovHkn1uucg
https://www.youtube.com/watch?v=hovHkn1uucg
01-04-18, 06:00 PM
#19
Lexus Test Driver
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