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Old 05-25-2016, 06:40 AM   #1
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Default 250whp is go?

Hi All,


Done alot of searching on here but cant realy find what im looking for for my specific build. Either too much info or too much varying info. Hope im not opening another post with alot of different info.

Car info:

Miata 1.6 1992. 52k Mileage stock block
Turbo: GT2860RS a/r .64 (2k miles)
MS2 PNP (reverant) with AEM type Boost solenoid.
Boost is set to not deliver full before 4k rpm (rod protection)
Rx8 yellow injectors (Rated +/- 0.5 of 500.0)
Currently running 15-17 PSI with 220whp and 285wNM (210 wTQ in ft/lb)

I keep reading alot of posts where people say its crazy to go over 200whp and people that say its safe to stay under 275whp... quite the difference i would say....

What would still be considered safe with a setup like mine? Im kind of looking for peoples experiences with high hp settings. Like is there anyone around that has run his 1.6 with a similar setup for 5k miles with 250whp?

Im planning to build a 2nd block (already disassembled) in a later stadium but why drive with a lower HP setting than the engine would alow me to in the meantime right? :P


Thanks in advance.

Jarno


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Old 05-25-2016, 09:21 AM   #2
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A lot of it depends on what type of driving you do. 220 wtq with a safe tune should be rock solid for reliability. Anything above that is asking for trouble if you track the car. 240 wtq will probably be fine on the street. There's a lot more mechanical empathy when only redlining the motor every now and then, and not flogging the car constantly to the point where everything is heat soaked. Anything in the 240-260 wtq range is all luck and mechanical empathy.
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Old 05-25-2016, 09:27 AM   #3
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rods are first to go at higher tq. Street driven and track driven car will have a different "safe" power level. I wouldn't up the boost untill you have forged rods.
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Old 05-25-2016, 12:05 PM   #4
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The best bet for longevity will be to avoid high torque low RPM situations. With that turbo on your 1.6 it likely won't be much of an issue.
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Old 05-25-2016, 01:37 PM   #5
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From a rod/crank/bearing strength standpoint, 1.6 = 1.8. The 1.8 and 1.6 literally use the same rods and bearings. The only difference is that the 1.8 has more bore and bigger valves and the later years flow even better. So you're looking at basically the same limits as the 1.8, power/torque wise. It's just harder to make the same level of power at a given level of driveability.

I think stock rods are in the danger zone above 240whp. They'll eventually fail, but how long depends on a lot of stuff. I've heard of rod failures below that HP level but I think they were on small turbo setups.

I think you should stick with 220whp in your 1.6 until you finished your second block. When rods go, they tend to take the block with them, which is more expensive in the long run.
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Old 05-25-2016, 01:55 PM   #6
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Thanks alot for the replies everyone. Very helpfull info. Guess ill just stick with what i got for now. The fact that this setup has proven itself on the track and street for quite a while is also of some value especialy considering the summer is starting here now. Would be a bummer to gamble and loose right b4 the summer comes.
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Old 05-25-2016, 02:08 PM   #7
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Quote:
Originally Posted by acedeuce802 View Post
Anything in the 240-260 wtq range is all luck and mechanical empathy.
I did 50K miles at 250 rwhp with a dozen or two track days in there. IME, rod failures are usually related to mechanical over revs, piston failures to detonation. Those 50K miles were done with 94-95 octane in the tank, closer to straight 100 octane for the track days.

After those 50K miles I took the motor out to build it, but that was because of losing the coolant, overheating the motor, and having low-ish compression on #4 (ring wear and tapered bores). The rods and pistons were fine.

--Ian
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Old 05-26-2016, 06:21 AM   #8
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Quote:
Originally Posted by codrus View Post
I did 50K miles at 250 rwhp with a dozen or two track days in there. IME, rod failures are usually related to mechanical over revs, piston failures to detonation. Those 50K miles were done with 94-95 octane in the tank, closer to straight 100 octane for the track days.

After those 50K miles I took the motor out to build it, but that was because of losing the coolant, overheating the motor, and having low-ish compression on #4 (ring wear and tapered bores). The rods and pistons were fine.

--Ian
Thanks. This is valuable information for me. Do you remember how much wheel torque you had at the time.?
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Old 05-26-2016, 02:14 PM   #9
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Originally Posted by jarno View Post
Thanks. This is valuable information for me. Do you remember how much wheel torque you had at the time.?
It varied over the years. Feb 2008 it was 244 rwhp, 233 tq: DSR Dyno tuning Feb 1 2008

--Ian
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Old 05-26-2016, 03:59 PM   #10
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Thnx very much for the reply
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