fp3575 q's...

[highintenzity4]

Currently running a 60-1 setup and looking to upgrade to the fp3575.... Question is will the fp 2.5 o2 sensor work well for over 600hp? Would upgrade to their 3 inch one but there 2.5 one bolts up to dsm downpipes.... Is there a huge difference between the two?

 

[94Jettameowpsst]

All i know about the turbo is that its pretty huge. Id say go 3 inch all the way just so you wont have to upgrade in the future. All i do actually know about the turbo is it has a 75lb/min comp wheel.....to me atleast, thats screaming 3 inch.

 

[Staytuned]

If your going to buy a 8-9 second turbo I would go with the 3 inch O2 housing.

 

[1fast97gsx]

Going cheap on the basics kinda defeats the purpose of upgrading to a turbo of that sort. What's a new O2 housing cost, $250 max?? Just get it.

 

[sunflashx]

Robert at FP told me they've had a car on their dyno making 600 whp with the 2.5" o2 housing.

That was a couple years ago though, they could probably give you a better idea now days what exactly the gains are from the 2.5" to the 3" o2 housing.

 

[highintenzity4]

Either way if I go with this turbo I need to buy a new o2 housing that fits the fp 30 turbo... Thing is the 2.5 one bolts up to mitsubishi downpipes( 2.5 necks tapers to 3) and I think with the 3 inch housing a full 3 inch dp is needed.. Anyone know where a complete 3 inch can be bought?

 

[sunflashx]

There isn't a bolt-on model available to my knowledge. Using the 3" housing requires the help of a muffler shop or a friend with a welder.

 

[1fast97gsx]

Hahn racecraft has a 3" O2 eliminating downpipe that is 3" from the flange all the way back. This is what I have on my car. The pipe fits perfect, looks nice and is very good quality.

 

[highintenzity4]

that hahn racecraft dp will bolt up to the fp 3 inch housing?

 

[NOSLO2PT0]

that hahn racecraft dp will bolt up to the fp 3 inch housing?

No. From my understanding, the 3575 utilizes FP's custom turbine housing, which requires a v-band clamp to connect the O2 housing to the turbine housing. In true FP fashion, most people that have the FP 3" O2 housing, also get the 3" v-band clamp to connect the DP to the o2 housing. Lots of v-band clamps, at $80ea, gets expensive.

Also, 3" o2 housing from FP is in the $400 ballpark range.

 

[highintenzity4]

I think the 2.5 one bolts up to mitsu dps without vband clamps, is this true?

 

[NOSLO2PT0]

I think the 2.5 one bolts up to mitsu dps without vband clamps, is this true?

Yes, it utilizes 2 bolts, like a normal dp does. However, be prepared to buy some nuts, weld them onto the flange of the FP O2 housing. Because the holes in the FP o2 housing are not threaded.

 

[Module Unknown]

that hahn racecraft dp will bolt up to the fp 3 inch housing?

Have you seen the exhaust side of the 3575? Take a look. (yes I know that's a 3065, but that side is the same)

Now go look at Hahn's Eliminator downpipe. Nope.

This is where things start getting expensive (well, even more expensive). You want 3", pay an arm and a leg for fp's exhaust pieces. Or have something fabricated.

What might work though... If you look at that last link and get fp's Custom 2.5" SS O2 Housing for FP30 Turbo, it looks like the flange from that O2 housing MIGHT end in the right position to mate up with Hahn's Eliminator Jr. downpipe. But it definately won't work with the elimintor since that has a 3 bolt flange after the O2 housing.

 

[94Jettameowpsst]

Why dont you just ask shep what he ran, considering the turbo that put him in the 8's was smaller than that.... I just think its kinda funny that you'd pay almost 2grand for a turbo but skim out on an o2 housing. To put in perspective, a gt42r (should belong on a mack truck) has an 85lb/min comp wheel. Dont get me wrong, you could probably make 600whp with a 2.5 inch but it'll be chokin the whole time.

 

[sleestack]

Yes, it utilizes 2 bolts, like a normal dp does. However, be prepared to buy some nuts, weld them onto the flange of the FP O2 housing. Because the holes in the FP o2 housing are not threaded.

The product pictures on the website are old, all of the FP30 2.5" O2 housings have downpipe flanges on them that heave threaded holes and come with OEM studs, all you need is your old nuts.

As far as the whole 2.5" vs. 3" goes. It may not be "choking" it as much as you think. The exducer diameter of the turbine is .050" less than the diameter of the 2.5" O2. So it isn't blocking any flow.

 

[NOSLO2PT0]

The product pictures on the website are old, all of the FP30 2.5" O2 housings have downpipe flanges on them that heave threaded holes and come with OEM studs, all you need is your old nuts.

.

I must have an older O2 housing then. I've had this guy for about 18 months. Not sure when you guys started with the new production.

 

[94Jettameowpsst]

Sleestack, not trying to argue here (just wanted to make that clear) Well if thats the case then why is there such a big deal about out flowing a 2.5in exaust and going with a 3 inch. If you can get away with a 2.5in dp or o2 housing, then whats the point going from o to O if the hot side of the turbo is o-that big?

 

[94Jettameowpsst]

Figured id post this here as well instead of starting a new thread. Say a turbo flows 700cfm, how is that calculated...cause i really dont know? Is that at peak boost or peak efficiency or what....kinda confused?

 

[sleestack]

Sleestack, not trying to argue here (just wanted to make that clear) Well if thats the case then why is there such a big deal about out flowing a 2.5in exaust and going with a 3 inch. If you can get away with a 2.5in dp or o2 housing, then whats the point going from o to O if the hot side of the turbo is o-that big?

I'm not saying it doesn't make a difference. All I am saying is that it isn't as big a difference as you might think. When comparing a 2.5" tubular O2 housing to a 3" tubular O2 housing you have to keep in mind that we are talking about 6-8". While that might mean alot to your girlfriend it doesn't really make that much difference in an exhaust WHEN it is immediatly following the turbo. The exhaust gases immediatley following the turbine wheel are super hot and moving at peak velocity (when compared to the gas moving through thre rest of the system). As the exhuast moves through the system it loses heat and density, therefore the smaller your exhuast the closer to the end, the more harm it does (the greater the restriction). I think that ideally your exhaust would start out the same size as your turbine wheel exducer then continue to gradually increase in diameter all the way to the end. Obviously this isn't practical in our car for ground clearence issues and costs.

Conversley, there might be a slight gain in response (turbo lag). I mean slight, as there should be a greater delta P across the turbine with a larger O2 housing. In real world testing, this gain has been so small that it has been difficult to actually measure using dyno. So there you have it. It's really nothing to bicker about, some people prefer the 3" because it is easier to recirculate the wategate back into it. Still some people just seem to be convinced that it makes a big difference, or may not be convinced but just base their decision on the princible of the matter and have the cash to spend. Either way you can't lose with the tubular design if properly constructed (or a cast EVO unit, where applicable, properly ported but that is a whole different subject).

 

[92GSXBaltimore]

Currently running a 60-1 setup and looking to upgrade to the fp3575.... Question is will the fp 2.5 o2 sensor work well for over 600hp? Would upgrade to their 3 inch one but there 2.5 one bolts up to dsm downpipes.... Is there a huge difference between the two?

if your maxing out your 60-1, then you are gonna have a little more to worry about based on your mod list, than your o2 housing(ie: stock internals). And if your still on those 650's you deff not maxing out that 60-1.

 

[highintenzity4]

havent upgraded my mod list... i have ross pistons, eagle rods, hks 272s, magnus manifold, 750s.

 

[Forces32psi]

i have run the 3575 w/ the 2.5" O2 housing #1 because of the price of the 3" O2 housing ($450) versus the cost of the 2.5" ($250) #2 because i didnt want to cut my downpipe and the 2.5" will bolt directly to your downpipe. #3 because i talked to robert and he said i wouldnt REALLY gain that much from the 3" as the O2 housing is the same size (not bigger) then the outlet from the hotside of the turbo as the 2.5".. i ran the 2.5" it worked fine i had VERY little lag w/ this setup on my 2.3.. it started to spool up at 3300 w/ the 9:1's. and i can still swap turbos around because i didnt cut and custom fab the 3" O2 housing to my $800 Thermal R&D exhaust..