Bigger Spearco Intercooler,HX40 and 3" piping

[ceedawg]

At present I have a 2.5 inch upper intercooling pipe leaving my Spearco intercooler (2-221)which has a 2.5 inch outlet and inlet.

On my present T3/T4 57 trim, the outlet of the turbo is about 2" which has 2" intercooler piping leaving which then goes to a 2" to 2.5" adapter connected to the inlet of my intercooler.

My new larger spearco intercooler (25 x 3.5 x6) not including the end tanks,I notice has a 3" outlet and 3" inlet.WTF

My holset HX40 has a compressor side outlet measuring 2.5" inner diameter with an outer diameter of almost 3". These dimensions are bigger than my present Garrett setup.

Presently on my car I have:

a ported 1g mani and ported 1g throttle body.

My head is ported with 1mm oversized valves.

I have 264,272 HKS cams.

Exh is 3" presently from turbo back.

I also presently have a turbonetics mani on the car but I will be using tubular TS mani and TS holset turbine hsing 16cm(A/R .77 to .80) or 18.5 cm(A/R .87 to .90+) turbine hsing.

Possibly setup with two 38mm tial wategates.

Because of this new FMIC with the 3" in/out, and the HX40 outlet , it looks like I'll have to go 3" on the piping.

Will there be any down falls going from 2.5" piping which is presently on the car to 3" intercooler piping on newer higher flowing HX40turbo and intercooler setup performance wise?

Remember take my mods listed above into consideration as well.

 

[Defiant]

More volume is more wasted supercharging, and more lag.

 

[ceedawg]

Well if you are using a big turbo ,how is that the case?
I'm noticing alot of EVO's using 3" piping with the GT35R's so it has also made me curious.

 

[GORBS88]

You dont NEED 3 inch by any means so if its a hassle then i wouldn't bother but if you have the room and such then go ahead, since the turbo is laggy already i doubt you will even notice.

 

[JWoodley]

I've been debating this as well. You might've just spurred me to start a new thread. =)

 

[bastard dsm]

the ic pipe sould be the same size as the throttle body,that seems to work best.

 

[absolute_DSM]

More volume is more wasted supercharging, and more lag.

Ditto x3, although its not that much to notice it, maybe a few hundred RPM, but enough for people to complain.

Havent you ever heard of reducers? Use 2.5" piping with reducers on the IC and turbo.

 

[JWoodley]

the ic pipe sould be the same size as the throttle body,that seems to work best.

Alright here are some rough numbers to work with:
80mm = 3.1 inches
90mm = 3.5 inches
60mm = 2.3 inches
52mm = 2.0 inches

So wouldn't the 80mm Q45 (97+) be the best option with 3" piping from the IC to the TB?

How would the 90mm perform with the .5" smaller piping? Would the throttle response from the 90mm be significant enough to justify it's use over the 80mm? I'm sure it's been covered, but I'm trying to gain enough of an understanding to put together a nice little writeup.

 

[ceedawg]

the ic pipe sould be the same size as the throttle body,that seems to work best.

Scroll down to post #96 in the Buschur forums. Seems like in this particular intercooler test Dave Buschur performed on this EVO,the 2.5" piping had a more positive effect vs the 3" piping:

Random FMIC information with a little turbo info mixed in..... - Page 10 - Buschur Forums

Ditto x3, although its not that much to notice it, maybe a few hundred RPM, but enough for people to complain.

Havent you ever heard of reducers? Use 2.5" piping with reducers on the IC and turbo.

This may be my only option.

Especially since as of right now ,I don't plan on chging the intake mani and stck 65mm TB which I also had ported.