hmmm, just bought a gt3082r


Just curious geoff but how can the gt3082r which is identical to the fp3065 be a mismatch? I mean, just looking at the success of the fp3065 it's done very well for dsm's, and now also for evo's. Looking at dsm times the fp3065 is slightly faster than any other all boost gt35r's and has been for nearly a year. Granted there's more potential for flow with the larger wheel and housings in a 3582r, and all it really needs is some one with the same or better setup to use a gt35r and beat it, but to have edged it out for so many months like it has makes me some curious about your conflicting results. My idea was that it would have far better midrange with an earlier onset of intake pressure but lack on the top.


Also do you guys offer those twin scroll t3 housings for the gt30r or were you just showing us that they are out there? Also internally, are they any different from the joints that ATP sells? Your's as you described was a 1.06 A/R where-as ATP's unit is only a .78.

 

Geoff, good information.
My original point was to say the twinscroll at an equivalent a/r vs an open flute will outspool and open flute design. I was not considering the potential gains from using the twinflute with a larger a/r to maintain equivelent spool vs an open flute. In light of your data it would seem the performance of the twinscroll is quite significant. Perhaps I need to ditch the Rev Hard Manifold and seek one of those divided housing cut for the GT30R turbine wheel.

BTW, I still have the RB front subframe and if it doesn't leave my house soon it is headed for the dump.
swap subframe for turbine housing?
Please PM.

 

So, even with the T4 1.06 a/r housing, you would expect this turbo to spool faster than a 35r with the T3 .82 a/r housing? Reason I ask is you told me with a 2.3/4088r the 1.06 would be the best and with a 2.0/4088r the .95 would be the best. I thought because of that, that with the smaller 35r the .85 a/r would work best. Is the T4 .85 a/r housing even an option, since you mentioned the T4 .95 a/r housing wont work on a 35r?

*edit* What about the T4 twin scroll turbine housing on your 3567r turbo as another option?

Are you going to have any production versions of a divided T4 manifold for the Evo? When I had spoke to you through e-mail a few months ago, you had said it would be custom made. Has this changed now that your working on some twin scroll options for the Evo crowd?

Also, from what I've seen of the HTA wheel Forced Performance devoloped, that is currently on Dave Buschur's car, there aren't any losses, and only gains in the midrange. Granted there's not much info about it, as Dave has the only working example right now, but based on his results, and the dyno charts he's posted, it looks awesome. Is there something I'm missing?

 

Jeff could tell you for sure but I think you'll find that the .85 and .95 turbine housings are specific to the GT4088R/GT4094R style turbos . The 1.06 is from some other turbo family based on a smaller diametre turbine so the A/R numbers dont really cross reference . Off the top of my head GT40 turbines are ~ 77mm OD and GT35 ~ 68mm .

In my own very narrow opinion trying to get better response from the generic GT3582R turbo by changing compressors is not the answer . For a while I thought smaller trim versions of its 82mm GT40 compressor would make a worthwhile difference but the twin scroll system does so many positive things to the world the engine see's on the exhaust side that it is a more complete solution . Sadly so many people can't see past a turbochargers compressor when really the turbine and housing end are the stars of the show .

I feel the bottom line is that forced induction is all about getting big engine torque from small engines but in doing so you get a large engine exhaust flow requirement to have to deal with . The ability to have the pulse separation and I assume better energy recovery from this expansion ratio business across the larger A/R divided passages seems to do the trick . I'm sure Jay could explain this larger divided housing and expansion thing if he has the time . ATM my dumb logic suggests that the exhaust gas energy will be highest when the exhaust valves first crack open , having the least path of resistance to the turbine means the best chance of giving it a real giddy up so the larger divided passage is needed to keep the gas flow unrestricted .
I think Geoff and Jay have hinted that A/R is critical so does this mean that there is a definate trade off of least restriction vs volume to have to fill and is this why A/R is not as directly tied to boost threshold as single scroll housings are ?

Cheers A .

 

Yeah I'm thinking you are correct about this. In looking at the pictures that Geoff posted of the T4 housing, it looks different than the version available for the 4088r/4094r. I had ASSumed since it was the same 1.06 a/r sizing, that it was in fact the same housing.

As far as the HTA turbo, that I think you are refering to, FP didn't just slap a different compressor wheel on the 35r. I believe they altered the shape of the wheel, to make it more efficient. The only negative effect of the new wheel is that the turbo surged quite a bit more than a standard 35r. The compressor cover was then ported, NO surging since, none what so ever. I haven't seen enough info on it to say it's superior to Garrett's design, but the early reports seem to back that up. Time will tell I spose..

 

the main thing to remember is that the turbine has a very important job -- it has to power that big compressor!! it is a mismatch based purely off the numbers. There are some people who say some turbos are mismatches, others are not. There is no question that mismatches, to an extent, can work well. The problem becomes that the turbine wheels moves relatively slowly considering how much air the compressor pushes. turbine efficiency is going to suffer, as is response. Even tho top end power/steady state power looks great on the dyno chart, it doesnt feel like that on the street. Its not nearly as much fun to drive, boost overall feels lazier on a mismatch turbo, thats the only way i can really describe it

the t3 .82 and 1.06 housings are extremely limited. very very rare. we may start selling them in the future, but right now they are pretty rare and very pricey.

the t3 .78 housings are quite common now and we sell them very often, particularly for our sr20 customers.

the 1.06 i was talking about is actually on a t4 flange. it is essentially a 1.06 twinscroll t3, but it has the bolt pattern of a t4

you guys are correct - the 35R turbine housing has nothing in common with the 40R turbine housing. A 1.06 40R housing is huge compared to this 1.06 35R housing.

the 3567 is another mismatch turbo. I am not particularly fond of this turbo but its become pretty popular with engines that REALLLY breathe like s2000 or k series hondas -- they tend to favor a mismatch a tiny bit more than most other engines due to their absurd amounts of cyl head flow stock

the full-race T4 production manifold is very close. we've been working really hard on it, as well as a few other innovative evo components/designs. Im confident a lot of people are going to like what they see coming out of full-race this year


i deifnately want it, and ill give you a turbine housing for it, but it wont be divided!! email me at geoff@full-race.com since i dont get on here too often

 

"6-blade 20G" is the term I use describe the feel of a mismatched turbo. Certain important aspects of feel and response cannot be measured on a dyno, but factor heavily into how the turbo is perceived when driven on the street.


A .78 A/R divided T3 housing converts a GT3076R from a laggy drag-oriented piece into a monster street turbo. If the cost and availability of the .82 A/R are detractive, it probably isn't worth the small functional difference.


Possibly a good option for a street driven GT35R.

 

That sums it up fairly accurately.

The effect of the size and/or volumetric capacity of the housing must factor in significantly, just as does the diameter and length of a collector in a race header, which has a common function (re: expansion ratios). After all A/R is just a ratio that doesn't take this into account.

 

i heard... twin scroll 3076 monster street turbo??? elab???

 

Keep up the great work Geoff! Eagerly awaiting your new offerings!

CJ

 

Geoff how long before the new twin scroll kits come out?

 

Very nice looking healthy.

 

And any idea on the price?

 

If every 3076R car felt like Drifto's car does, there would never have been any notion of 3076Rs being laggy. The response is so good from idle on upward, the car just feels like it's always trying to lurch forward at all throttle settings. The overall throttle feel of the car is most impressive.

 

It's too early to say. The .82 A/R divided housing is a completely different housing ("from the ground up") from the .78.