PP Intake timing
09-01-08, 09:25 AM
#1
PP Intake timing
Ive been looking at scalliwags old housing build. I know he copied Kens port timing for making his housings. Alot of other guys have gotten ahold of MFR housings, and have been able to measure their ports, or racing beat ports. Well talking to the speedsource guys this past weekend, they run racing beat housings, due to the problem of supply, but they mentioned they got alittle more torque and mid range power from the angle of the port.
I will have the tools to machine any port needed, and Im thinking of threading the tubing as well. Does anyone have any information, charts, experience with the port timing for PP motors? The car isnt a drag car, so Im looking for more useable power band, and the engine will only see 8500rpm. I will most likely me using someone elses exhaust port timing, such as pineapple racings templates.
Also due to not running higher then normal rpms, are ceramic seals still recommended, or would using stock mazda seals be fine? And what is the recommendation of using used housings for a PP motor? I would only use used housings if they looked very good, if not I will spring for new housings.
I will have the tools to machine any port needed, and Im thinking of threading the tubing as well. Does anyone have any information, charts, experience with the port timing for PP motors? The car isnt a drag car, so Im looking for more useable power band, and the engine will only see 8500rpm. I will most likely me using someone elses exhaust port timing, such as pineapple racings templates.
Also due to not running higher then normal rpms, are ceramic seals still recommended, or would using stock mazda seals be fine? And what is the recommendation of using used housings for a PP motor? I would only use used housings if they looked very good, if not I will spring for new housings.
09-01-08, 10:10 AM
#2
Old [Sch|F]ool
Ceramic seals IMO should *only* be used with new housings. That said, the friction/longevity benefit is there no matter what RPM you run. The much-vaunted R26B engine had an operational redline of 8000rpm.
My opinion, again, is that if you're not sure your housings will be workable, start off with junk-ish housings. (Some flaking is OK but scoring is right out) That way there's no real loss if you screw up. You can always learn from the first experience and use that knowledge for a better set.
My junk housing, old seal P-port made more cranking compression than my decent-housing 13BT street port with new seals does after breakin. It also got better fuel economy, too... but nowhere near the power
Anyway the P-port's intake closing was about 10-15deg earlier than my current engine.
My opinion, again, is that if you're not sure your housings will be workable, start off with junk-ish housings. (Some flaking is OK but scoring is right out) That way there's no real loss if you screw up. You can always learn from the first experience and use that knowledge for a better set.
My junk housing, old seal P-port made more cranking compression than my decent-housing 13BT street port with new seals does after breakin. It also got better fuel economy, too... but nowhere near the power
Anyway the P-port's intake closing was about 10-15deg earlier than my current engine.
09-02-08, 01:10 PM
#3
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the 2mm steel seals are fine up over 9000 (we ran 9400 for a season, on junkyard stuff). you should at least get new springs and use a lot of premix, they seem to chatter at high rpms.
you really need to find some sae papres for the port timing, they have one from 84 with lots of graphs, intake open vs VE, intake close vs VE, plus intake and exhaust lengths
you really need to find some sae papres for the port timing, they have one from 84 with lots of graphs, intake open vs VE, intake close vs VE, plus intake and exhaust lengths
09-02-08, 04:51 PM
#4
Old [Sch|F]ool
Was that 9400 actual RPM or 9400 stock-tach RPM (which is like probably 8500 actual given the typical 10% fudgefactor)
You should have seen the look on Logan's face when I told him I wanted to run my car to 9500. The engine should be good to 9800-ish... We compromised on 9000... as it turns out the stock exhaust kills power by 8500, and the injectors are maxed out at that point anyway. The torque curve basically falls off massively past 7500.
You should have seen the look on Logan's face when I told him I wanted to run my car to 9500. The engine should be good to 9800-ish... We compromised on 9000... as it turns out the stock exhaust kills power by 8500, and the injectors are maxed out at that point anyway. The torque curve basically falls off massively past 7500.
Last edited by peejay; 09-02-08 at 04:54 PM.
09-02-08, 05:38 PM
#5
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9400 was the rev limit in the e6x... so it was real
we pulled the rear housing off, bearings are tired but everything else looks fine...
we pulled the rear housing off, bearings are tired but everything else looks fine...
09-02-08, 09:40 PM
#6
I want to run no more then 8700rpm-9k max, I was preferably like to set my shift points at 8500. I was thinking of using stock seals due to housings. If Im able to use a good used set to make my housings, Ill use stock seals. If i need to buy new housings, I will use carbon.
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