i think the question re the GT35r versus ??? might be one of the most interesting questions that could be raised on this board.

the GT35r is the turbo of choice for the single conversion as it's 62 pounds of air and 400-450 range fits the overwhelming amount of FD objectives. further, it is ball bearing and has Garrett's good build quality.

is it best in class for our rotaries?

the primary problem i have w it is it's small turbine.

the 6.386 sq inch compressor matches against a diminutive 5.171 turbine. it might work fine on a piston engine that optimises at 1320 F EGT but w a 1600 F rotary... i would be looking for more hotside.

Sean at A-Spec has been offering an alternative, the GT3574. recognizing the the need for more flow he added a P trim wheel raising the hotside to 5.89. that moves the relationship from 81 to 92%. (other have also constructed similar variants)

as far as i am concerned a ported street/track rotary running a 60-70 pound turbo should be able to make 400 SAE hp at 5500. do it and you have an untouchable street rocket. the BW R85/TEC 300 gets it done. notice the relationship between the hot/cold... notice the size of the hot side.

a couple of interesting turbos are the S362 (nice hot side) and the BW S300s...

i like journal bearing turbos and consider them offering great value V BB. my experience indicates that journal bearing turbos MUST have a 360 degree thrust bearing to cope w the rotary heat.

i would welcome others who have more experience here to discuss the GT35r versus????

here's a list of turbos in the GT35 neighborhood w average cold and hot wheel average areas in sq inches...w the % relationship... for more see my sticky "Turbo comparison."

Borg Warner S300SX 8375......................6.383..................5 .408.......................85
GT3582R........................................... ........6.386..................5.171.............. 81
HTA 3582R (Forced Performance)............ 6.386.................5.171....................... 81
GT3574 (A-Spec and others)....................6.386.................. 5.89.(P).................92
GT3082R........................................... .........6.386.................smaller than GT35R..?
Precision 6262...........................................6.4 48..................5.408.....................84
Precision 6265........................................... 6.448.................5.885 (P)...............91
BW, R85, TEC300...................................... 6.667...................6.93...................... 104
BW Bullseye S362.......................................6.69... .................6.31.....................94
HTA 3586 (Forced Performance).................6.839................ ...5.171....................76
Borg W S300s 61/87(2010 catalog)...........6.946..................6.928... ..................100

howard

 

I realized that everyone talks about garrett considering ernie made so much power with the garrett. However comparing similar turbos like the t60 & gt35/ T78 & GT42 & t66

it would be nice to see which company holds the best turbo on the same size. like what your doing!!

IMO IF THE GT35 YOU HAVE ISNT BALL BEARING THE BORG WARNER SEEMS TO MAKE MORE POWER




But to add on i will say that my gt42 does spool faster than the T78. Hell i turn off the car and it takes at least 4 minutes before the wheel stops spinning

 

What effects on the compressor map does having a divided t4 housing have on the gt35r? Or is it subjective?

 

I posed a similiar question, getting very few replies, and at this stage wondering if changing to a S362 woill be worthe the effort considering Im using a 12a and still havnt treid the 1.06 rear

Here:https://www.rx7club.com/single-turbo-rx-7s-23/bw-s362-vs-gt35r-890803/

feel free to pass opinion guys.

 

I have the aspec version. The turbo makes good power and is responsive but I use it on track car and IMO the turbo is to small. Im not looking for more power, the car has plenty but I think a larger compressor wheel would help take the load off the intercooler. When I swap this out I will probably be looking at a T04R/Z with a GTQ turbine, still want to make 400-425ish but do it much more efficiently to keep temperatures down.

 

Turbine housing wont really effect the compressor map, for that you would be looking at turbine maps and few publish them.

Fd neal a GTQ turbine will be noticeably laggy compared to your current setup. Things to consider would be running water pre compressor or swapping just the compressor wheel to a TO4R/Z comp-wheel. Every car we had GTQ turbines on the owners wound up switching back down to a P-trim with the only exception being drag guys. The track guys just didn't like the lag coming out of the corners.

~S~

 

Sean, I thought the idea is to downsize the turbine housing while upsizing the turbine wheel to keep similar response?
Ive actually moved my water from the elbow to pre-compressor for this coming season and will see how that changes things. If i dont need to swap things it would be great as power delivery and response is awesome.

 

Yes to a point, keeping nice wheel ratios is also good as well but the next issues to arise would be mass and inertia of the turbine wheel, or kinda just being physically bigger than the engine needs for a given range. You could have a great wheel ratio and smaller sized A/r but if the physical mass is large enough the motor will have to overcome it regardless. The GTQ wheels are pretty large and if you had a motor that operated mainly above 5k RPM I would say it would be nice. But it will not do good for you coming out of a tight turn, long sweeper maybe. Keep in mind that A/r is a function of turbine size as well. Going from a 68mm wheel with a 1.0 P-trim housing to a 74mm wheel in a .84 P-trim housing is a bit different than going from a 68mm 1.0 P-trim housing to a 79mm Q-trim wheel and housing. You'll basically be running a 40R sized turbine wheel and housing.

~S~

 

that makes sense. they are tied together, but compressor != turbine (insert face palm icon)

But, to add to howards original goal of this thread, i understand there are two major factors in the hot/exhaust side of the GT35r. t3 vs t4 flange. and divided vs undivided.

wait a sec, there are more, but that seems to be the main concerns about manifolds mating with the gt35r