Thinking about porting my spare s4 irons
09-14-12 | 05:56 PM
#26
yep, a heavy flywheel should be a bit more friendly at lower speeds and deceleration but it's not something you want with the bridge still wanting more past 9,000 RPMs.
i guess a scatter shield would be the compromise, heh.
i guess a scatter shield would be the compromise, heh.
09-14-12 | 05:57 PM
#27
i'm sure the PP is more streetable, with large bridges though my experience has been that they suck *** to take off from a stop and like to buck and surge below 3k as well as a serious lack of torque compared to a stock port setup.
3k is where most decent turbos will begin to pull, and will outrun an n/a without much effort.
yes the power band is broader than stock ports but compared to the rest of the power band anything below 3k feels like the motor is simply dragging it's *** and it is.
3k is where most decent turbos will begin to pull, and will outrun an n/a without much effort.
yes the power band is broader than stock ports but compared to the rest of the power band anything below 3k feels like the motor is simply dragging it's *** and it is.
I personally like the standard full Bridgeport, Great torque over a street port and very street-able, These port will be best for using nitrous oxide, I have shaven over 2 seconds off the clock and gained over 20 miles an hour with a 150 shot of nos. This was with old school early engines.
09-14-12 | 06:00 PM
#28
depends what your idea of streetable is i suppose, a well tuned bridge usually isn't very notchy at low speeds but the purebred builds like to skip and hop around unless you load the engine down.
the PPs differ mainly due to the size of the ports, of course a large PP is going to want to move, the smaller PP engines are going to be more streetable.
the PPs differ mainly due to the size of the ports, of course a large PP is going to want to move, the smaller PP engines are going to be more streetable.
09-14-12 | 08:37 PM
#29
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yeah, the big difference with the PP vs the stock port is just that it has a narrower AFR window where its happy, the stock engine runs between 15:1 and 10:1, the p port window is smaller. too rich and it gets mean and nasty, too lean and it wants to be mean, but can't.
i can see tuning using a MAP sensor would suck, i did a chevy V8 like that, and with the a/t it basically ran on 2 bars! one was idle, one was everything else, hard to get it even close!
with the carb, pulling less intake vacuum actually makes it run WAY better, the vacuum just pulls exhaust gasses into the intake, buck buck buck.
lower the intake vacuum and it'll run like a stock car
i can see tuning using a MAP sensor would suck, i did a chevy V8 like that, and with the a/t it basically ran on 2 bars! one was idle, one was everything else, hard to get it even close!
with the carb, pulling less intake vacuum actually makes it run WAY better, the vacuum just pulls exhaust gasses into the intake, buck buck buck.
lower the intake vacuum and it'll run like a stock car
09-14-12 | 10:40 PM
#30
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From: Macon, Ga
Originally Posted by peejay
Sounds about right. I idle at 5btdc and at 1500(ish) it's right on around 60kpa manifold pressure. (Atmospheric is around 93kpa around here)
The perverse thing is, having a heavy flywheel means you can run more ignition advance, since the bucking is damped out by the 26lb mass of weight. I will admit that I have to shift to Neutral to coast down hills now, compared to the heavy-flywheel engines. Oh well, it will finally get me off my butt and go to computer control of ignition timing instead of just using the distributor.
But I'll tell ya. 9lb flywheel and four 42mm blades and a TIGHT compression engine means the thing zings like a dirtbike engine when you touch the throttle. Downshifting is a breeze now.
Oh yeah, I forgot that part - besides all new seals (kind of a first for me) I have some supersecret resurfaced rotor housings. No, they're not from that guy. Or that other guy.
The perverse thing is, having a heavy flywheel means you can run more ignition advance, since the bucking is damped out by the 26lb mass of weight. I will admit that I have to shift to Neutral to coast down hills now, compared to the heavy-flywheel engines. Oh well, it will finally get me off my butt and go to computer control of ignition timing instead of just using the distributor.
But I'll tell ya. 9lb flywheel and four 42mm blades and a TIGHT compression engine means the thing zings like a dirtbike engine when you touch the throttle. Downshifting is a breeze now.
Oh yeah, I forgot that part - besides all new seals (kind of a first for me) I have some supersecret resurfaced rotor housings. No, they're not from that guy. Or that other guy.
that guy is cool as hell.Sent from my iPhone using RX7Club
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