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Will Front Mount Change Boost Pressure?

kidafa

By kidafa,
in Engines & Forced Induction

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kidafa Veteran

kidafa

Posted
Posted

Hi All,

Going to be putting a front mount in the stagea some time this week :thumbsup: Just wondering if the boost pressure will change at all after installing a frount mount? As I dont have a gauge or anything to check with. Im running stock boost but will be getting a electronic boost controller in the next few weeks :( thinking of a Greddy Profec B spec 2. By the way car is stock, so will be going from the side mounted cooler to a frount mount.

thanks in advance,

chris

SiR_RB Grand Master

SiR_RB

Posted
Posted

i was running 7ish psi with just a 3" cat back and pod.

once i put a 3" stainless steel dump/frontpipe and 3" hi flow cat, boost went to around 8.5psi

then front mount shifted boost to around 9.5psi (maybe a wee bit more )

R31Nismoid Grand Master

R31Nismoid

Posted
Posted

I would suspect no change on a stock level car.

The factory cooler really isnt "that" bad of a restriction in the factory setting.

Obviously more boost, larger turbo etc then there are benefits there :thumbsup:

gotRICE? Veteran

gotRICE?

Posted
Posted

Best way to check is to do a before and after dyno.

I never did on my R33, but after a full 3" split dump, decat and HKS catback, and R34 side mount, the dyno boost reading was showing 11.2psi on stock solenoid. No bleed valves or anything.

Will be doing FMIC when i get back from the states so would be interesting to see if i get an increase too.

Suck it up, dyno before and after and let us all know :thumbsup:

sonoramicommando Collaborator

sonoramicommando

Posted
Posted
Guys, please forgive my ignorance, but i don't get why boost increases. Logically speaking, if you increase the volume (by using a larger intercooler), shouldn't pressure go down? Please enlighten me :thumbsup:

front mount tends to have better flow capacity (as in flow rate) than stock one so you get less pressure drop across the core.

that's why you see more boost at the plenum.

increase in volume may give more lag, depends on flow capacity.

bumble_bee Rising Star

bumble_bee

Posted
Posted

i agree as above..

and lag can also be created by the length of intercooler piping..

wrx seem to get more lag wen fitting a large fmic...

skylines dont get this problem..and if u think u are getting lag, its becoz u need more boost!! :banana:

quarkgun Proficient

quarkgun

Posted
Posted

Ok, i think i understand now :). So the volume increase, in a closed system, would lower the pressure - but the increased rate of flow actually compensates for that increased volume to the point where across the system, the total pressure of air going to the engine increases...

So, how is the flow rate measured, i assume cfm or something. Anyone know what the standard intercooler (on an R33) flow rate is?

sonoramicommando Collaborator

sonoramicommando

Posted
Posted

Mmm not sure that's how I would put it.

I'd like to think the flow rate increases with larger cross sectional area in intercooler pipes and/or core - whichever is the smallest and lag increases with the total volume of the entire intake system, post turbo.

this is probably overly simplified and the construction of the pipe/bends and core would have substantial influence over it.

of course there would be frictional pressure drop along the length of I/C pipes and the cooler itself.

so, I'd would say a system with a cooler with shorter length across end tanks and shortest possible piping would be best for flow for a given cooler core area and I/C pipe diameter.

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