Q: about boost drop off.
Q: about boost drop off.
ok i was wondering today.... we all know how the evo spikes, then drops off
i drive a F-550 Turbo Diesel for work, and that truck does not appear to have the same spike and then fall, like the evo does... it goes strait to 30 + or - psi and holds.. depending on load and what gear.
why is that?
is it because the diesel motor only revs to 3k? is it because its diesel? does it have to do with the size of the turbo and boost level?
i drive a F-550 Turbo Diesel for work, and that truck does not appear to have the same spike and then fall, like the evo does... it goes strait to 30 + or - psi and holds.. depending on load and what gear.
why is that?
is it because the diesel motor only revs to 3k? is it because its diesel? does it have to do with the size of the turbo and boost level?
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iTrader: (38)
Joined: Aug 2005
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From: Virginia Beach, Virginia
I'm new to the EVO world but not new to turbos... apparently this is a weakness in the stock boost controller because some people are able to hold that boost all the way to redline with a good aftermarket EBC and almost with a good MBC. So it's not the engine demand exceeding the turbo's capability.
The ECU, engine computer, actually tapers the boost for you in stock form.
The turbo itself is a little too small to hold higher boost levels than about the low 20's all the way to redline. There is only so much air you can flow out of the turbo before it can't maintain pressure also there is the turbine size considerations too.
The stock unit is very good at what it does in stock like boost levels but for a higher boost level a slightly larger turbo will help. There are a number of threads on turbo selection and why they work and don't work.
The turbo itself is a little too small to hold higher boost levels than about the low 20's all the way to redline. There is only so much air you can flow out of the turbo before it can't maintain pressure also there is the turbine size considerations too.
The stock unit is very good at what it does in stock like boost levels but for a higher boost level a slightly larger turbo will help. There are a number of threads on turbo selection and why they work and don't work.
