How much to fix head gasket?
10-12-2003, 09:25 PM
#17
Rennlist Junkie Forever
Silverbullet951
The 94 is certainly better than the 91 trash sold here on So Cal... but it's still 94. It's a long way from 100 unleaded or 106-108 leaded.
The main thing to remember is that machinists, especially the typical head machine shop, almost always recommend milling the head "to clean it up".
I hate when I hear that. You can't put the metal back.... EVER.
Only take off when necessary to make flat.
The 94 is certainly better than the 91 trash sold here on So Cal... but it's still 94. It's a long way from 100 unleaded or 106-108 leaded.
The main thing to remember is that machinists, especially the typical head machine shop, almost always recommend milling the head "to clean it up".
I hate when I hear that. You can't put the metal back.... EVER.
Only take off when necessary to make flat.
10-12-2003, 11:45 PM
#18
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Tony G,
I see you mentioned 106-108 unleaded - can we run that in the 951's?
I didn't think you could even without a cat?
When I track my car, I only use 100 unleaded, but if I can use the leaded stuff, it might be more of a safety margin?
TIA! Steve
I see you mentioned 106-108 unleaded - can we run that in the 951's?
I didn't think you could even without a cat?
When I track my car, I only use 100 unleaded, but if I can use the leaded stuff, it might be more of a safety margin?
TIA! Steve
10-12-2003, 11:52 PM
#19
Rennlist Junkie Forever
3 Turbos
You are correct. Leaded fuel will trash/clog a cat.
When racing and making serious HP, you'll not be running a cat in the first place, thus running real fuel at the track is an option (or should I say mandatory).
In a sustained WOT condition (track), 100 octane unleaded is good... but unfortunately isn't not good enough.
If you're making 350WRHP - 400WRHP, the cylinder pressures are very high, and is the propensity to detonate once the system gets real hot.
On the street, things don't get anywhere near as hot as they do on the track, so for short bursts.... lower octane is acceptable (minimum 95)... and I'm not talking about dyno bursts either.. which are very short in duration with long cooling periods in between runs.
Below that, and you risk detonation. On the track, you can easily get into preignition with 100 octane (unless you have a serious intercooler or water/alcohol injection, etc..)
You are correct. Leaded fuel will trash/clog a cat.
When racing and making serious HP, you'll not be running a cat in the first place, thus running real fuel at the track is an option (or should I say mandatory).
In a sustained WOT condition (track), 100 octane unleaded is good... but unfortunately isn't not good enough.
If you're making 350WRHP - 400WRHP, the cylinder pressures are very high, and is the propensity to detonate once the system gets real hot.
On the street, things don't get anywhere near as hot as they do on the track, so for short bursts.... lower octane is acceptable (minimum 95)... and I'm not talking about dyno bursts either.. which are very short in duration with long cooling periods in between runs.
Below that, and you risk detonation. On the track, you can easily get into preignition with 100 octane (unless you have a serious intercooler or water/alcohol injection, etc..)
10-13-2003, 12:41 AM
#20
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TonyG,
I thought unleaded and leaded had something to do with lubrication of the valve guide seals or something also.
Also aren't the materials for the valves or seals made/designed with different lubricates in mind from leaded or unleaded fuels?
I thought unleaded and leaded had something to do with lubrication of the valve guide seals or something also.
Also aren't the materials for the valves or seals made/designed with different lubricates in mind from leaded or unleaded fuels?
