25-04-2012, 12:03 PM
Trouble is even in here there's lack of knolage going on,
A 9mm pump could make 200 hp say on one turbo, but less on a bigger one....due to rpms...
The problem with bigger turbos is the power moves up the revs, and this then has a totally different effect on pump delivery, VE's basically dont like revving at all in stock form, you need to do alot of work to the timing system / fuel system to make them function remotely decently at higher rpms, a typical 11mm conversion consisting of say a stock pump, with 11mm head and govmod, which is what most people build themselves at home, is capable of stupidpendous amounts of power at 2000-3800rpm, like literally 250-300hp of fuel no issues at all, but the issue most of you will be getting is your blowers, that are capable of 250-300hp, (well not many running turbos that big but you catch the drift) dont come in to there peak until 3500-5500rpm +, by this point the ve is running out of flow / timing, and you make naff all power, but still able to blow CHRONIC fuel down low, and just turns into a vicious circle trying to make power up high, making low down worse and worse.
Theres arguements against 9 /10/ 11/12mm heads, each has gains / loss's. and at the end of the day, depends what your trying to do, but for home conversions where you cant calibrate A timing and B flow, id go to 10mm at most, and only then after maxing out the 9mm pump in the first place, as nothing will work as stock better than the 9mm as thats what the pump was calibrated for in the first place.
This is obviously referring to IDI, as with DI, its a totally different game altogether.
A 9mm pump could make 200 hp say on one turbo, but less on a bigger one....due to rpms...
The problem with bigger turbos is the power moves up the revs, and this then has a totally different effect on pump delivery, VE's basically dont like revving at all in stock form, you need to do alot of work to the timing system / fuel system to make them function remotely decently at higher rpms, a typical 11mm conversion consisting of say a stock pump, with 11mm head and govmod, which is what most people build themselves at home, is capable of stupidpendous amounts of power at 2000-3800rpm, like literally 250-300hp of fuel no issues at all, but the issue most of you will be getting is your blowers, that are capable of 250-300hp, (well not many running turbos that big but you catch the drift) dont come in to there peak until 3500-5500rpm +, by this point the ve is running out of flow / timing, and you make naff all power, but still able to blow CHRONIC fuel down low, and just turns into a vicious circle trying to make power up high, making low down worse and worse.
Theres arguements against 9 /10/ 11/12mm heads, each has gains / loss's. and at the end of the day, depends what your trying to do, but for home conversions where you cant calibrate A timing and B flow, id go to 10mm at most, and only then after maxing out the 9mm pump in the first place, as nothing will work as stock better than the 9mm as thats what the pump was calibrated for in the first place.
This is obviously referring to IDI, as with DI, its a totally different game altogether.
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