ALPSTA

iTrader: (3)

I went for Garrett GTX35R because 13b and GT35R are proven to be a good combination. Not saying EFR is a bad turbo but I wouldn't risk having fitment issues and waiting even longer than GTX for few rpms quicker spool and 10-20 more hp.

Liborek

If compressors are operating with similar efficiency at certain flow and pressure ratio, and VE% of whole system is same, then there isnīt reason why turbo with larger compressor should produce more power. Answer lies is turbine.

BorgWarner 7670 in terms of compressor dimensions and flow rate is comparable to GTX3076. But in terms of turbine dimensions, this BW turbo has larger turbine than one frame bigger Garret, also available with true T4 housing, not flange

GT30 turbine: 60 mm inducer, 84 Trim
GT35 turbine: 68 mm inducer, 84 Trim
BW EFR 70mm: 70 mm inducer, 88-89 Trim (Trim number from BW training guide)

Not considering design of wheels - both manufactures have something, its pretty clear that turbine of BW flows most. Hence increase in top end power through lowered turbine inlet pressure - higher VE%
Of course, GTX3076R in full load operation reaches full boost earlier - turbine is smaller. But on platform like rotary, where turbine flow is almost everything for making good power, especially on ported engines, BW hotside is win. Unfotunatelly, I must admit, that compressors are rather high PR oriented, so probably not the best match for high flow, low boost application

Liborek

Could you share your goals? It would be pity if this turbo wouldnīt meet your expectations...
As above - you canīt quote power differences across different platforms. Rotary engine needs turbine flow. There must be reason why some people are coupling GT3582R compressor to P-Trim turbine

ALPSTA

iTrader: (3)

Mine is a GTX35R T4 1.06 divided. This turbo will meet and hopefully exceed my expectations because I am not building my car for competition so my goals have wide tolerances. At the start I will be satisfied with anything betweeen 400-450whp @ 15-17psi with reasonably quick spool which is one of the reasons why I went with 3.5" dp and dual wastegates The other reason I picked this turbo is, it still has potential for more hp when I decide to do alky injection and increase boost.

Yes I can't talk numbers without comparing maps, trims etc. but I was just saying BW may be better than an equivalent turbo but for someone who is not trying to squeeze out every single hp out it's not worth the wait and the experiment.

We will have to wait for my results and others' with BW EFR to have something conclusive.

raffi@full-race

JZG, I just signed up to the RX-7club to check up on some of my customers waiting on their 9180 and came across this thread. Is there any way you can shoot me an email, raffi at full-race.com or PM me

I tried to PM you and also email you but apparently the forum is set up similar to GranTurismo5, I have to get to level 3 for PMs and level 10 for emails.. haha!

ElCapoRx7

Yo raffi whats up! Its Ariel.... Stop messing around on these damn forums and get me my turbo lol hope all is well I'm here having a good time at pan American event in atco raceway in new jersey

Turblown

iTrader: (12)

At the end of the day engine build quality will make WAY more difference than any turbo technology....I've seen over 1000rpms difference in spool between the difference in " Ok " and great compression with the exact same setup and dyno..

raffi@full-race

Hey buddy! I knew that was your username when I saw it! Hah. Hope you had fun at the event, hit me up this week sometime and I can give you an update for the delivery!

Liborek

Well, by numbers and trap speeds posted by GT35R owners, Iīm pretty sure that turbine will choke any additional flow. Exhaust pressure goes up, VE% goes down, BSFC is worse... it seems to happen around 500 HP level. Its just to much of compressor for given turbine on rotary application...

Then why even bother with GTX line-up? There is no need for experiment, we have compressor and turbine maps, with few educated guesses you can determine how given combination will perform at full load....

Something cunclusive in rotary community
It would be nice, if someone would do comparison of similar sized turbochargers from Garrett, BW, Precision etc. and not only print some dyno sheets, but tell how turbo performs in real world situation - like on Nasioc forum.... But I donīt see this happening here....

So common sense will have to do But why use brain when you can copy bandwagoned setup

ALPSTA

iTrader: (3)

I don't know what you're trying to say.

GT35R is a popular turbo and from everything I've read it is suitable for my goals. GTX35R is supposed to be slightly better version of it with improved response and hp so why not get that one if I can afford it.

A lot of things seem to happen over 500hp and turbo would be the least of my worries if I ever get there.

But now that you know my goals, I'm curious what non-bandwagon turbo you would recommend?

It has to have the quickest response possible but still make easy 400+ whp and has to have some room for increased boost, race gas or alcohol injection.

Liborek

Yes.
Because its waste of money. Gains are at higher flow and pressure ratio, but turbine will hold you back, same as on ordinary GT35R...

400+ whp is really vague, most dynojet numbers should be quoted as HP@crank...
Just look at this threadhttps://www.rx7club.com/single-turbo-rx-7s-23/autox-fd-dyno-956766/

Lets assume that you really want around 400+hp. Garrett GTX3076R has enough compressor flow to support it. Turbine will surely pose quite high backpressure, but it is cost for responsiveness.
Borg Warner S256 has similar compressor dimensions with much bigger turbine and is much cheaper. It also would make what you want, but without much room to grow... Then you have S360, S363, Precision line up etc. There are many options, but its up to you what you really want.

By looking on compressor maps, Garrett seems to be true leader, very high flow at broad PR. Borg Warner stuff sometimes excels with very high efficiency numbers, but they shine only at high PR. Precision unfortunatelly doesnīt have any maps...

On the other hand, Garrett mates these high flowing compressors to smallish turbines. Ok for small displacement piston engines, bad for rotary.

As in other thread, 55mm billet compressor with GT35R hotside would be win, but its custom unit....

Trots*88TII-AE*

iTrader: (11)

Most often something is "bandwagoned" because it simply works. Go tried and true, larger P-trim exhaust wheel mated to 35R compressor wheel. It is a great setup for rotaries for all the aforementioned reasons, and will net you among the best spool for a 400-500 whp turbo.

After using a billet wheel precision turbo, I'm somewhat skeptical of the benefits on a rotary, only because we cannot make use of the higher PR's where they tend to shine (depending on porting, stockports would benefit more from them than aggressive intake porting). But let's keep that quiet, I don't want to wake the trolls.

Liborek

Or because people are so lazy to use brain and common sense to research for themselves. Will it meet goals? Yes. Is it best option? No.
Agreed. Powerband can be simply adjusted by turbine housing. Still there is room for even better response with smaller compressor of later technology.

Are you crazy? Stockport engine canīt run high boost

Seriously, I think that billet line-up doesnīt indicate higher flow only at high PRīs. Garrett stuff shows it clearly. Its just that some people probably thought, that when compressor map indicates xx more flow at given boost, it will make zz more power. It would only happen with big enough hotside and revving engine much higher, granted that VE remains good...

What turbo you used? Describe setup

ALPSTA

iTrader: (3)

https://www.rx7club.com/showthread.p...power+response

Most importantly I talked to Sean about my goals and my choice of turbo. Now you might say he suggested this turbo cause it is his kit, but I don't think he cares, he can make a kit for most turbos and price it accordingly. We almost went with tial housing but I wanted T4 incase I wanted to upgrade the turbo in the future.

One of the other reasons I went with Garrett over another turbo is, if I decide to change the turbo in the future I can sell the "famous" Garrett GTX35R in a day and for a good price whereas it's not the case with BW S series turbos or any other mix and match turbo (I'm not in US so market here is not as big).

So you see, you accuse people of not using their brain or jumping on the bandwagon but what may not be the best option for you may actually be the best option for them when you don't look at it from one angle.

Trots*88TII-AE*

iTrader: (11)

Turbo was a precision 6768, open volute 0.96 A/R T4 on a streetported TII block. Didn't get a chance to play with it much though, so I shouldn't base my opinion on my old setup. I will agree with you that on a GT35R the turbine would be a greater restriction than the cast compressor wheel. A newer F1 series P or Q trim wheel in BB mated to a GTX35R compressor wheel would be a great setup IMO.

neit_jnf

iTrader: (17)

you called? https://www.rx7club.com/single-turbo-rx-7s-23/gtx35-compressor-p-trim-1-15-turbine-what-expect-951050/

Trots*88TII-AE*

iTrader: (11)

sick. I would take that over the EFR series any day, although I am interested in seeing the results from both lines.

A-Spec Tuning

^^^ This is a excellent statement. ^^^

As for the choice that was made by Alper, He was looking for something that offered decent response and good power that would get him 400-450whp. We covered many options, dual gates, single gate, 3574, 3574R, 35R, GTX35R, 6262, 6265. some smaller and some larger. I can only lay out the info for a customer I can explain the pros and cons and let them decide, and if they make some really poor choice I can tell them so and let them know why. His setup will perform well, it will meet his goals.

I have ran 62mm GT turbines with 1.06 housings side by side with P-trim .84 housings for comparison. I have run .84 P-trim housings side by side with 1.0 P-trim housings. I have ran BW "extended tip" wheels side by side against GT wheels (40R frame). I've ran 62mm "billet" compressors against 61mm cast wheels. I've ran 80mm BW's against 80mm Garrett's I can say the same for 88's as well. Also ran 1.10's 1.20's 1.32 on just about every turbine you can think of from 70mm range to 100mm range. Compared Precision 65mm turbines to 68mm turbines, changed compressor A/r's both through options of the shelf as well as custom machined units. I can go on and on and on and on...

Lazy brain or bandwagoning is a fair statement but so is bandwidth racing in your internet super car. I constantly have to fight (used loosely) with customers who are simply saturated with so much info from online they are outthinking themselves or what their needs are. They honestly think they will feel a noticeable difference in power and response when going from a 60mm compressor versus a 61mm compressor, or a .81 housing versus a .82, or .82 versus a .84. Guess what? You'll get more of a difference noticed with what Elliot said above. Will you notice a difference with a .84 divided versus a .81 undivided? Sure. Will there be a difference in a .84 divided and a 1.0 divided? Sure. Are there massive gains to be had by running a 1.15 over a 1.0? No. Not on a street car, it's simply not worth it. Do you need a 1.32 with 96mm turbine to make power? I guess maybe. We seem to do just fine with a smaller turbine housing, making the same power or more than others.

Could I have recommended Alper get a Billet 58/65 for better response? My guess is (and I'd say it's pretty educated) it would be close enough that any other thing in the system could make the difference. Should I at that point tell him go with the smaller compressor? Yes when pushed it will make power but response will be what... almost identical to the average guy driving his street car with little if any experience to reference to?? So I should then handicap the potential of the compressor side for the possibility of such a massive improvement in response? A 58/65 would be a very nice turbo for someone just wanting simplicity of a single but decent response and maybe 400whp. 58/62 would be great if your after simplicity and want 350whp. My personal suggestion for him was either a 3574R or 62/65. Why? Because the difference in 61mm to 62mm is nothing. Yet I could get the 65mm turbine on there and simply put with a .84 and dual gates it would easily meet and exceed his 450whp maximum mark if setup and tuned well. You will see no gain running a 62mm billet compressor versus a 61mm 35R compressor under 20psi on a 62mm turbine. Been there. Can you reach 500whp on a 62mm turbine, yep been there, as have others on here. Does he want 500whp? No not really, if it happens great. Look at goodfella's car running 62mm GT turbine with a 1.0 A/r T4 housing we made. He's making 480whp and good response despite having the larger mass of the cast 67mm compressor to push. If Alper does want to run more the 20psi on the compressor it will certainly be a better option than the cast wheel. Point being there are a bunch of different ways it could have went, all are so close to each other that any will be a decent choice and meet his goals. Part of the decision for the garrett choice I'm sure is simply parts availability if needed, Garrett is infinitely larger than Precision and I doubt getting Precision parts in Turkey is a option if needed. Trying to make him feel as though he made wrong choice is silly at best.

You're right RPM will play a role in it, turbine A/r's wont much unless you shifting your power band upwards to appreciate the little gain you get for the response lost down low. We build our engines here for shift points of 10.2 or 10.5k Running a larger A/r and using the better flow of the compressor at those RPM's wont be used by 99% of the guys in this section. I'd bet I could count on one hand how many have actually wound their cars out about 9.5krpm regularly.

enzo250

good post sean.. Most don't realize and get caught up in all the internet hype...

Sounds like you've tested more then me..

What did you find between garrett vs Borg vs Precision.
I'm just curious and wondering if it's the same as me..

A-Spec Tuning

I wouldn't say I've tested more than you sir, maybe tested different things, you're one of the few on here who's posts I always know are backed with actual knowledge through experience and who's opinion I trust.

As far as what I've noticed between them, it's not the turbo that makes the car. It's only part of the puzzle. Sure there can be some differences, but there is simply more to it than BW is better or Garrett is better or this size is for sure going to make more power over that size etc. It's simply not a given.

I'll add I don't buy marketing crap from manufacturers. Extended tip wheels spooling faster than BB units is one example of BS pushed by one company, or billet wheels make more power by another. I proved both to be BS and when I called them on it they backed down and started saying things like well "under these conditions" or "you didn't say you were using the turbo in that application", c'mon really?? Think about how Garrett had a whole page posted up showing how billet wheels make no more power than cast wheels, when they first offered them. Of course not... it was the same aero, but it didn't take long for people to start posting on forums about how billet wheels offer no benefit. Clearly Garrett's marketing worked on slowing lost sales to the other guys somewhat. Yet now with new aero Billet wheels are the best choice supposedly.

The same could be said for engine building on this board as well. Way too much bickering over details that aren't usually needed(especially on porting and apex seals). It gets very tiring having to "fight" with customers over something some other engine builder says is the "only way" yet that engine builder has almost zero experience about the topic at hand, only what they read online, it's always easier to say something doesn't work when you haven't done it.

ALPSTA

iTrader: (3)

I don't want to repeat what's already been said but I must mention Sean was very helpful and patient with my turbo choice we've considered many options for my turbo set-up. 3574R was one of the reasons I contacted Sean, then he explained pros cons of lots of different turbos but in the end it was my call and I went for GTX3582R T4 1.06 divided.

One of the deciders for my choice was the popularity of Garrett turbos in my country and that I can sell it in a day if I decide to buy something else. The more 13b specific a turbo becomes the harder it will be to sell considering I own 1 of 3 fd3s in the country.

Again like Sean mentioned I am not after 500+whp at this stage. The choice of turbo and its cost would be the least of my worries, may I decide to reach that power level.

This basically sums it up

Jobro

iTrader: (2)

Glad to see the results are pouring in

ScorpionT

iTrader: (3)

Im not surprised by the lack of results. The rotary guys are really only going to use the 8374 and 9180, and neither is very accessible at this time. I know a handful of guys who have had the 8374, and they were either the first units, or they were just delivered in the last few days (literally).

the_glass_man

iTrader: (2)

I've heard that the 9180 is an eight month wait. Who's got that much time to waste?

ScorpionT

iTrader: (3)

Wont be that long. I already had my twin scroll 7670s delivered, and I know guys who have their twin scroll 8374. The 9180 wont be all that much longer, I would say in less than 2 months they will start shipping.