Single Turbo RX-7's Questions about all aspects of single turbo setups.

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Old 12-28-11, 02:10 AM
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Efr 7670

BWAHAHAHAHA!!!!!












I've actually had this for about a month already...well, it's been at my house anyway. My roommate took pics for me since I'm out of country right now.
Old 12-28-11, 06:13 PM
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Awesome turbo man! Can't wait to see it in person.
Old 12-28-11, 07:12 PM
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Thanks Dave! Yeah me neither LOL! Can't wait to put it on, too.
Old 04-02-12, 12:23 AM
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Pretty much finished installing, finally. Now I just need to get an oil drain for the turbo to work with my setup, can't seem to get this problem licked. Also picking up a couple more clamps tomorrow for the IC couplers and I'll powder coat the IC and piping, and also make some ducting.

Old 04-02-12, 01:32 AM
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what is this, about a 500whp (rotary) turbo?
Old 04-02-12, 01:36 AM
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Fweeeaaaakin schweeeet!

ps...A/R size?

Last edited by mannykiller; 04-02-12 at 01:39 AM.
Old 04-02-12, 07:05 AM
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Originally Posted by Cosmo_TT
what is this, about a 500whp (rotary) turbo?
Compressor peak flow should support about 550 hp@crank, but map is rather high PR oriented. It will flow that 64 lbs/min at highest speed line, no matter PR, but 13B around 7500 rpms will consume all that airflow at less than 25 psi boost I.e. 2.7 PR. And 2.7 PR @ peak flow is waay outside of efficiency range. This will cause two things, high discharge temperatures and high turbine backpressure. Former can be solved by good intercooling, but later is a problem.

But given the fact that we don't know OP's goals, this is just my ranting
Old 04-03-12, 12:51 AM
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Originally Posted by Cosmo_TT
what is this, about a 500whp (rotary) turbo?
Not sure yet, maybe Liborek is correct haha.

Originally Posted by mannykiller
Fweeeaaaakin schweeeet!

ps...A/R size?
Thanks! It's the 1.05 external wastegate option.

Originally Posted by Liborek
Compressor peak flow should support about 550 hp@crank, but map is rather high PR oriented. It will flow that 64 lbs/min at highest speed line, no matter PR, but 13B around 7500 rpms will consume all that airflow at less than 25 psi boost I.e. 2.7 PR. And 2.7 PR @ peak flow is waay outside of efficiency range. This will cause two things, high discharge temperatures and high turbine backpressure. Former can be solved by good intercooling, but later is a problem.

But given the fact that we don't know OP's goals, this is just my ranting
I'm not really sure what all you are saying here LOL, I'm just looking for a turbo that responds pretty quick. Also, I'm pretty sure my old turbo was the cause for my oil burning so I'm hoping this fixes it, too, and I wanted to try something new also. The IC is new also (well, old, but different from the previous setup), smaller core and *hopefully* smoother flowing end tanks, which HOPEFULLY will aid spool.

I'm gonna powdercoat the IC end tanks and IC piping black on this one also.



Got the oil drain issue remedied and started the car...crappy video though...
Old 04-03-12, 02:41 AM
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Very nice I'm very interested in seeing how this works out. Whats your setup?
Old 04-03-12, 10:10 AM
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Hell yea!! i'm at work and wish I could see the vid haha. I think you'll be very happy with that turbo. I was looking into an efr as well but they were so hard to get a hold of I ended up just sticking with the gtx series. But the Sierra Sierra TIme attack evo uses is... and I think you'll have no problem with response. Those Crazy compressor/exhaust wheels are rad! Can't wait for results. Are you getting a re-tune? Looking great!
Old 04-03-12, 12:28 PM
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Get that thing tuned and to a dyno. Lets see the hype.
Old 04-03-12, 12:34 PM
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^ya, it'd be nice to see some actual data showing these turbos are indeed "better", or not...we shall see
Old 04-03-12, 04:52 PM
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Originally Posted by speedjunkie
I'm just looking for a turbo that responds pretty quick.
Well, compressor is physically small and Gamma-Ti turbine wheel is very light, so whole rotating assembly should have very low inertia so it should be very responsive.

But I must ask, what are your power goals and intended boost levels?

What I was saying basically means, that these units were designed for low displacement piston engines running at high boost. They can operate with very high pressure ratio and they are efficient in these areas at high flow. Not so much at low pressure ratios and high flow...

For low boost, high RPM, high flow stuff I.e. rotaries, these aren´t exactly the best match. But have a look bellow, I ploted how your turbo should work at 15 psi (assuming) on 13B. Its not that bad
http://www.turbodriven.com///perform...6_wrsin=92044&

Originally Posted by silverTRD
^ya, it'd be nice to see some actual data showing these turbos are indeed "better", or not...we shall see
No one is saying that they are better. Compressor maps are showing all the info you need and even very basic parameter like wheel ratio can give very good idea how well certain turbocharger will work on certain application.

These turbos are really unique in turbine material and "gains" from this can't be measured on dyno, only in real world situations like transient response, boost response between shifts etc.
Old 04-03-12, 10:38 PM
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Originally Posted by RX7WEEE
Very nice I'm very interested in seeing how this works out. Whats your setup?
What do you mean exactly by "setup"? Are you talking about engine mods, turbo, IC, fuel, everything? Or just something specific?

I have a large street port from IRP, RA Super Seals (I believe all other internals are stock but I don't remember), stud kit, oil passage porting, OMP adapter running 2-cycle and also premixing, Supra pump with Kenne Bell BAP, CJM fuel kit with ID 725cc and 2000cc injectors, Xcessive equal length LIM, Mazmart water pump, Garfinkle oil pan brace, I don't really remember everything haha.

Originally Posted by mannykiller
Hell yea!! i'm at work and wish I could see the vid haha. I think you'll be very happy with that turbo. I was looking into an efr as well but they were so hard to get a hold of I ended up just sticking with the gtx series. But the Sierra Sierra TIme attack evo uses is... and I think you'll have no problem with response. Those Crazy compressor/exhaust wheels are rad! Can't wait for results. Are you getting a re-tune? Looking great!
Yeah I did a lot of research into this turbo as far as components and technology and figured I'd give it a shot. I know there are other RX-7 owners doing these but it seems like everyone else is doing the much larger frame ones. I wanted to go with something smaller for response, and this doesn't seem too far off from a GT35R anyway. I figured it would be pretty hard to get ahold of but I got it fairly quick. They started with the small ones and moved to the large ones I think, because it seems like the smaller ones hit the market a lot sooner than the large ones. Yeah the Sierra Sierra EVO is killin it! I'll be getting a retune, but my buddy will tune it for the drive to DGRR in a week or two. If it's a good tune, I'll stick with that for a while probably lol.

Originally Posted by Islander
Get that thing tuned and to a dyno. Lets see the hype.
Well, that's what sucks. I don't think this will be seeing a dyno, not for tuning anyway. Pretty much every time I get on a dyno something bad happens. The first time I lost the oil seals in my brand new turbo (that was my fault though, running too big an oil line with no restrictor, new to single turbos lol) and I lost my engine last January. I was also maxing out at 300hp one time with the 500R, and it was because I was only getting 6v to the fuel pump. That one wasn't so tragic, just unfortunate at the time lol. Basically though, my car hates dynos for some reason. The only time I've had somewhat success on a dyno is when I'm just doing a pull to see what it's making, but tuning almost always kills something.

So while I really want to provide dyno info on this turbo, I can't promise anything lol. I'm not going to risk my engine or something else for that lol.

Originally Posted by silverTRD
^ya, it'd be nice to see some actual data showing these turbos are indeed "better", or not...we shall see
Maybe someday, but it won't be tuning lol.

Originally Posted by Liborek
Well, compressor is physically small and Gamma-Ti turbine wheel is very light, so whole rotating assembly should have very low inertia so it should be very responsive.

But I must ask, what are your power goals and intended boost levels?

What I was saying basically means, that these units were designed for low displacement piston engines running at high boost. They can operate with very high pressure ratio and they are efficient in these areas at high flow. Not so much at low pressure ratios and high flow...

For low boost, high RPM, high flow stuff I.e. rotaries, these aren´t exactly the best match. But have a look bellow, I ploted how your turbo should work at 15 psi (assuming) on 13B. Its not that bad
http://www.turbodriven.com///perform...6_wrsin=92044&

No one is saying that they are better. Compressor maps are showing all the info you need and even very basic parameter like wheel ratio can give very good idea how well certain turbocharger will work on certain application.

These turbos are really unique in turbine material and "gains" from this can't be measured on dyno, only in real world situations like transient response, boost response between shifts etc.
Yeah I did quite a bit of reading about the technology that went into this, but I'm not smart enough to read compressor maps and all that lol.

I'll probably run around 20-25psi, which is what I've been running on the 500R. My power goals I don't care about as much, I'll get what I get. Especially considering I lose so much at 6000ft altitude anyway, and I won't know what it actually makes unless I get on a dyno closer to sea level. I figured it would do about the same as the 500R but I don't care as much about that as I do about response, which for me will be told more with the butt dyno anyway.

Well hopefully it will be even better than that considering I'll be pushing 5-10psi more than that, but we'll see lol.

I'm right there with you on that last part, I want to see what this will do in real world situations. Hard to convey to someone over the internet though lol.
Old 04-04-12, 11:14 AM
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Originally Posted by speedjunkie
Yeah I did quite a bit of reading about the technology that went into this, but I'm not smart enough to read compressor maps and all that lol.
Really, its not that hard. There are many threads on this site which concerns the reading of the compressor maps and BorgWarner MatchBot is really nice tool. There are even tutorial videos how to use it.

Originally Posted by speedjunkie
I'll probably run around 20-25psi, which is what I've been running on the 500R. My power goals I don't care about as much, I'll get what I get. Especially considering I lose so much at 6000ft altitude anyway, and I won't know what it actually makes unless I get on a dyno closer to sea level. I figured it would do about the same as the 500R but I don't care as much about that as I do about response, which for me will be told more with the butt dyno anyway.
Hard to convey to someone over the internet though lol.
Don't expect miracles 500R has 67mm compressor rated at 75 lbs/min, this one has only 57,2mm compressor rated at 64 lbs/min. These flow rates on its own on good engine should support 660 HP@crank for former and 560 HP@crank for later.
Note:I'm mentioning flow rates itself, not saying that given turbo is able to do it

Problem is that turbocharger is volumetric device and these mass flow rates happens at certain corrected conditions, IIRC at sea level pressure - 14.7 psi and 68°F temperature. Your altitude has lower absolute pressure, this will be compensated by turbocharger itself, it will just work at higher pressure ratio. But since the compressor inlet is limited to certain volumetric flow, lower air density, in your case about 80% of STP will support only 80% of peak mass flow. So even with 25 psi in midrange and about 20 psi in top-end (this turbo simply can't support more) you will be limited to about 450 HP@crank at these boost levels.

Still, when you look bellow on the compressor match, its not very good. From about 5500 rpms and up efficiency falls of drastically which causes very high compressor outlet temperatures and high backpressure. Both these things aren't very good, nor for power production, nor for reliability. High backpressure will actually hurt volumetric efficiency, so peak power will be even lower.

http://www.turbodriven.com///perform...6_wrsin=92044&

It will be interesting how it will work out, don't be afraid of dyno, just be prepared, many things can be recognized and sorted before hitting the dyno. If you know that you have certain mechanical or electric problem, solve it first.
Old 04-05-12, 01:13 AM
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The oil line for the turbo and the fuel pump rewire I should have known about but didn't. I had zero indication that my engine would go last January, and my car was running like a top before that.

I test drove the car today. I'm SUPER happy with this turbo. I didn't boost too much, because I was told to take it easy for the first few hundred miles. But even with little boost (.28 bar) I could feel the car pulling at 2k RPM and it felt pretty strong at 3k-3.5k. Not only that, it feels as though there is very little spool lost between shifts.

Now I have a vacuum leak I have to find though haha. Ugh.
Old 04-05-12, 03:58 PM
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in cabin video? stop being so stingy... I havent gotten to hear our fabulous motors in a while!!
Old 04-05-12, 05:16 PM
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He has the 1.05 option.
I think you plotted for .92?



Originally Posted by Liborek
Well, compressor is physically small and Gamma-Ti turbine wheel is very light, so whole rotating assembly should have very low inertia so it should be very responsive.

But I must ask, what are your power goals and intended boost levels?

What I was saying basically means, that these units were designed for low displacement piston engines running at high boost. They can operate with very high pressure ratio and they are efficient in these areas at high flow. Not so much at low pressure ratios and high flow...

For low boost, high RPM, high flow stuff I.e. rotaries, these aren´t exactly the best match. But have a look bellow, I ploted how your turbo should work at 15 psi (assuming) on 13B. Its not that bad
http://www.turbodriven.com///perform...6_wrsin=92044&

No one is saying that they are better. Compressor maps are showing all the info you need and even very basic parameter like wheel ratio can give very good idea how well certain turbocharger will work on certain application.

These turbos are really unique in turbine material and "gains" from this can't be measured on dyno, only in real world situations like transient response, boost response between shifts etc.
Old 04-05-12, 05:19 PM
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Question to Junkie:

Is there a reason you went twin scroll? I,m thinking of doing a vband since 13b isnt supposed to have scavanging issues??
Old 04-06-12, 01:19 AM
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Originally Posted by mannykiller
in cabin video? stop being so stingy... I havent gotten to hear our fabulous motors in a while!!
HAHA, I didn't really see the point in doing an in cabin video until I can really boost on it, but I'll take one if you want haha. We're going on a cruise tomorrow night, if I can remember I'll take the go pro along and do some filming, or I can wait til Saturday. Don't expect too much though, I'm trying to keep it well below a bar. I will say this though, it freakin boosts so fast it's caught me off guard a couple times. I hit over 14psi/1 bar by about 3k without even realizing it, and it's not like I was even getting crazy, that's pretty light driving.

Originally Posted by d k
He has the 1.05 option.
Indeed I do.

Originally Posted by d k
Question to Junkie:

Is there a reason you went twin scroll? I,m thinking of doing a vband since 13b isnt supposed to have scavanging issues??
IIRC, all the midsize and larger turbos are twin scroll automatically, only the smaller frame EFRs are single scroll. But from what I've always heard, twin scroll are supposed to be better for response anyway, by splitting up the exhaust pulses so they can hit the turbine wheel separately (and opposite each other) instead of letting them blend together.

I'm not sure what you mean about v-band and scavenging issues though. What do those have to do with twin scroll or single scroll? LOL maybe I'm just confused. Please elaborate.
Old 04-06-12, 01:51 AM
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Need a 20b FD.

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Originally Posted by speedjunkie
What do you mean exactly by "setup"? Are you talking about engine mods, turbo, IC, fuel, everything? Or just something specific?

I have a large street port from IRP, RA Super Seals (I believe all other internals are stock but I don't remember), stud kit, oil passage porting, OMP adapter running 2-cycle and also premixing, Supra pump with Kenne Bell BAP, CJM fuel kit with ID 725cc and 2000cc injectors, Xcessive equal length LIM, Mazmart water pump, Garfinkle oil pan brace, I don't really remember everything haha..
That pretty much answers my question.

I was more wondering what ems, water injection or not, pump gas/race gas how much boost you wanted to run. etc etc

I'm looking at this turbo for when I go single and want 100% of the information I can get about it. I'll be bugging you. Thanks
Old 04-08-12, 01:28 AM
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Oh OK. I have an APEX'i Power FC, FJO water injection, pump gas, and I'm probably going to go for 20psi, maybe a little more. But definitely not over 25.

That's cool, bug me all you want.

Unfortunately I might be rebuilding my engine. Ever since I was still breaking it in last year it's been smoking/possibly burning oil. Most of my troubleshooting has led me to believe it's burning oil, but a couple things lead me to believe it isn't, so needless to say I'm getting really aggravated and I just want it to stop smoking.

Either way, this turbo is awesome lol.
Old 04-08-12, 08:22 AM
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I don't think you would see more than 380-400 wheel Horsepower on a 13B Rotary. Honestly it's going to be pushing a lot of hot air at anything past 20 psi and your EGT's and back pressure are going to get uncomfortably high.

I personally feel that this turbo is just too small for our engines. The smallest EFR I'd go with is the EFR8374. You don't happen to have EGT gauges or back pressure gauges off hand do you? I'm interested to find your results either way.

I'm also not entirely sold on the EFR product line. They look fantastic on paper, but it seems that the results thus far are less impressive than the hype that's been generated for these turbos.
Old 04-08-12, 05:44 PM
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Again, I don't care as much about HP level as I do response. But we'll see what it does. I think it's funny when people talk down something that hasn't even been tried yet lol. Why not just wait and see what happens?

I do have dual EGT, one on each rotor. Unfortunately they aren't exactly evenly spaced from the exhaust flange like I would have liked, but that won't matter for just seeing what the temps are at a given time, boost pressure, etc. I don't have any logging capability yet though. And I do not have back pressure sensors. At this point I don't plan on racing this car, just having fun with it.

This turbo is giving me what I'm looking for so far, which is fast spool, and I haven't even used much of its potential yet. It seems to be working well for Sierra Sierra lol, so I'd say it's probably a great turbo. If its not what you're looking for for your goals then so be it. But not everyone is looking for what you want.

Also, I don't want to go much more than 20psi because I don't want to have to deal with race gas. Not yet anyway.
Old 04-08-12, 09:16 PM
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I rode in his car on the cruise....while he wasn't boosting it hard because of the break in period....that sucker spools quick.....I am a guy who loves the stock twins because of the response and the lower rpms torque/power. This turbo seems like it comes on really low...and would probably be a beast in the low/mid range rpms.....I can't say anything about the upper rpm range as he is breaking the turbo in and didn't want to push it.

I totally agree with Speedjunkie's approach.....I personally don't see the advantage to running a huge turbo that kicks in the upper rpm range....when you might be able to take advantage of a smaller turbo that kicks in at lower rpms....but gives up a little top end power. We do a lot of street driving and probably hit some canyon roads up.....its more attractive to me to have a turbo that can pull in the 3-6K RPM range and at a higher gear....then a lower gear and a **** ton of power...which makes it harder to drive for us non-professional drivers. Area under the curve is what makes me excited.....and also linear curves......the graphs that look more exponential scare me for usable driving power. I am excited to see what his car feels like when its broke in and ready to go after some tuning. If my stock turbo system ever failed.....I would seriously look into this turbo....seems like a perfect set up for something I would consider.


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