Back again
15 years ago
Saturday, July 11, 2009
At last!!
Rick came over and helped me bleed the Maserati BiTurbo clutch. Amazingly it worked!! We took the car out and for the first time I was able to finally drive the car with a working clutch and working steering. As I got heat into the exhaust, the air / fuel gauge I just installed started to work and was stable in the stoich range as I was on the throttle. The boost was set to 5psi after the intercoolers were in the air flow (but not yet flowing coolant). The next step will be to finish the intercooler install, get an alignment, and set the boost.
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Awesome! I wish I could have been there. Are you planning on doing any of the IC work this week?
ReplyDeleteIt's very doubtful that I will be taking any days off work unless my project skips ahead and I am not needed there. I'm hopeful that I can do a little work this weekend but we're supposed to be on Staten Island this Saturday.
ReplyDeleteThis comment has been removed by the author.
ReplyDeleteDo you have A/F targets you're trying to hit? Or aiming for stoich?
ReplyDeleteNot to speak for Bob, but I think his main goal was to allow monitoring of the A/F ratio during the fitment of the ICs and the subsequent increasing of boost pressure. With the carb being essentially 'open-loop', the A/F gauge will at least give some manual feedback on how well the fuel is keeping pace with the air.
ReplyDeleteYeah thats right. The gauge is an analog gauge but without numbers just a stoich, lean, and rich area. For the most HP we'd probably want it on the verge to a little in the lean but I mainly want it for the assurance that I'm not running super lean when I up the boost.
ReplyDeleteGotcha. This combo of turbocharging and carbs is new to me. Just for reference I know the Sube tunes usually run stoich-ish in CL low-load situations, and they trend rich for more power - in the 11.mid's for max attack. That's when you know the Sex Panther is on the prowl.
ReplyDeleteHi Derrick,
ReplyDeleteI've always heard that lean was more power vs rich. Do you think they are doing this for 1) added cooling benefits of more fuel 2) safety for fear of premature detonation or 3) some other reason?
thanks,
Bob
1) Probably
ReplyDelete2) Probably
3) Probably
The Sube's generally run in the 11-16 psi range one I believe 8.5ish compression ratios.
Let me dig around a little to see if I can find out "why".
I think when you're tuning NA engines, you get some benefit (power) out of running a little on the lean side. In a turbo engine, the benefit of a lean mixture is almost certainly overwhelmed by the fact that you're ramming large amounts of air into the engine. You could probably gain a few extra hp by going lean, but why risk the detonation when you've just gained 100hp via increased boost?
ReplyDeleteThere's also a thought in my head about having some unburnt fuel in the exhaust manifold which can be ignited to increase exhaust gas temp and therefore flow. This may be mostly done in racing applications to assist in 'anti-lag'.
Yeah they did that in F1 when they had turbos but I don't think they would be doing it in a production model. I would bet the cooling aspect of more fuel as being their main reason.
ReplyDeleteWRC does it too...and I think Subaru and WRC have something of a relationship. That and DMizzle was discussing aftermarket modders who are liable to do all sorts of nutty things. Anyhow, I agreed with you that it was mostly used for protection against detonation.
ReplyDeleteOh, and the Solstice GXP Z0K package has anti-lag on a production car.