Thinking of going Semi P port
02-20-12, 02:06 AM
#1
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Thinking of going Semi P port
Thinking of going semi.
Can anyone share info on the benefits. I've "heard" that HP shifts to the right so you need to rev a lot higher and will lose low end HP.
Any info at all is appreciated
Thanks,
Anthony
Can anyone share info on the benefits. I've "heard" that HP shifts to the right so you need to rev a lot higher and will lose low end HP.
Any info at all is appreciated
Thanks,
Anthony
02-20-12, 11:59 AM
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My opinion, based on dyno graphs of various setups is, that there is no loss of low-end power but since VE curve is so flat even at very high rpms, it makes peak power in narrow top-end range, assuming flat boost curve. Close ratio gearbox would be needed for taking advantage of it.
On the other hand, "lesser" porting style (stock, streetport) have inferior top-end VE, but its better to have peak HP at lower rpms but carry it for 2000 rpm band. This is powerband IMO. More boost will be needed for given output obviously, but right sized turbocharger will gain efficiency at higher PR and there is no reason to fear added heat from boost if intercooling and fuel is good for given combination.
Overall, large overlap setup will be more delicate on turbo sizing, tuning and exhaust setup and less flexible in regards of gearing and driveability.
On the other hand, "lesser" porting style (stock, streetport) have inferior top-end VE, but its better to have peak HP at lower rpms but carry it for 2000 rpm band. This is powerband IMO. More boost will be needed for given output obviously, but right sized turbocharger will gain efficiency at higher PR and there is no reason to fear added heat from boost if intercooling and fuel is good for given combination.
Overall, large overlap setup will be more delicate on turbo sizing, tuning and exhaust setup and less flexible in regards of gearing and driveability.
02-23-12, 05:06 PM
#9
After much debate on wether adding my two inexperienced cents or not, I decided to post what I had planed, and had to postponed for a couple of years...
My plan was to run semi pp on my dd car, however my plan was to have two intake manifolds and maps. For the track run the semi PP manifold and map, and for DD, swtich to the non semi PP manifold, and tune.
I guess the beauty of semi PP is that you can go from semi to non with a manifold swap, something you cant do with a bridge.
My plan was to run semi pp on my dd car, however my plan was to have two intake manifolds and maps. For the track run the semi PP manifold and map, and for DD, swtich to the non semi PP manifold, and tune.
I guess the beauty of semi PP is that you can go from semi to non with a manifold swap, something you cant do with a bridge.
02-23-12, 11:28 PM
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After much debate on wether adding my two inexperienced cents or not, I decided to post what I had planed, and had to postponed for a couple of years...
My plan was to run semi pp on my dd car, however my plan was to have two intake manifolds and maps. For the track run the semi PP manifold and map, and for DD, swtich to the non semi PP manifold, and tune.
I guess the beauty of semi PP is that you can go from semi to non with a manifold swap, something you cant do with a bridge.
My plan was to run semi pp on my dd car, however my plan was to have two intake manifolds and maps. For the track run the semi PP manifold and map, and for DD, swtich to the non semi PP manifold, and tune.
I guess the beauty of semi PP is that you can go from semi to non with a manifold swap, something you cant do with a bridge.
02-28-12, 11:26 AM
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I have not seen any increase in power going from a turbo charged bridge port to a turbocharged semi.
But what i have seen is longer lasting apex seals. The reason for this is is the fuel "in our case we use methanol so it even helps more" acts as a coolant for the apex seal everytime it passes over the semi it picks up a nice drink of methanol.
Those that have made 900rwhp will start to notice that even on methanol the cumbustion will cut right through a apex seal without running lean.
Hope this helps.
But what i have seen is longer lasting apex seals. The reason for this is is the fuel "in our case we use methanol so it even helps more" acts as a coolant for the apex seal everytime it passes over the semi it picks up a nice drink of methanol.
Those that have made 900rwhp will start to notice that even on methanol the cumbustion will cut right through a apex seal without running lean.
Hope this helps.
02-29-12, 04:20 PM
#13
I have not seen any increase in power going from a turbo charged bridge port to a turbocharged semi.
But what i have seen is longer lasting apex seals. The reason for this is is the fuel "in our case we use methanol so it even helps more" acts as a coolant for the apex seal everytime it passes over the semi it picks up a nice drink of methanol.
Those that have made 900rwhp will start to notice that even on methanol the cumbustion will cut right through a apex seal without running lean.
Hope this helps.
But what i have seen is longer lasting apex seals. The reason for this is is the fuel "in our case we use methanol so it even helps more" acts as a coolant for the apex seal everytime it passes over the semi it picks up a nice drink of methanol.
Those that have made 900rwhp will start to notice that even on methanol the cumbustion will cut right through a apex seal without running lean.
Hope this helps.
You sir are the man
03-04-12, 06:09 PM
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For a long long time i ran just a big streetport. The best e/t i ran with the streetport is still my PB of 7.17.
Last year we changed to a semi pp. We have been chasing 'issues' with the car and as yet we haven't run any quicker with the semi BUT it's making at least the same power with less boost.
We have not lost any bottom end power and i don't have to rev the engine any harder than i used to(11k).
My PB 60 ft time is a 1.010 and this was with the semi pp launching at the same 2 step rpms as with the streetport(8800RPM).
Hope this helps
Last year we changed to a semi pp. We have been chasing 'issues' with the car and as yet we haven't run any quicker with the semi BUT it's making at least the same power with less boost.
We have not lost any bottom end power and i don't have to rev the engine any harder than i used to(11k).
My PB 60 ft time is a 1.010 and this was with the semi pp launching at the same 2 step rpms as with the streetport(8800RPM).
Hope this helps
03-29-12, 03:10 AM
#20
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Thanks for all the advice on this, I picked up a spare shortblock and going to make that one the semi and leave the streetport in the car running for now.
Anthony
Anthony
02-03-15, 03:53 PM
#24
i know this threat is old but i searched but couldn't find anything else about semi pport.
i want to ask if anybody know (try,have any experience) with the combination of semi pport and semi bridge port
i want to ask if anybody know (try,have any experience) with the combination of semi pport and semi bridge port
02-25-15, 09:42 PM
#25
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