Alright, I've got Richard rebuilding my engine at the moment. (Awesome guy by the way, Great work Rich!!) He's street porting my engine right now, and I'm thinking about upgrading my turbo set up.

http://cgi.ebay.com/ebaymotors/T3-T0...A1%7C72%3A1171

I was thinking something like that, but it needs an external wastegate and I don't know what size would be good for that.
I'm also a total newbie when it comes to forced induction on any engine so tips and hints would be awesome!

Thanks,
Scott

 

You need to figure out how much flow your engine requires at various boost and rpms then look at the compressor maps of the turbos you are interested in.
If you are flowing more or less then your turbo wants to at a given boost level it will not work efficiently.
After market turbos generally have a wide range of efficacy unlike oem ones. The oem turbos are often tuned only for a particular engine.

The compressor maps of 3 common turbos are listed below.

OEM on Nissan SR20DET
OEM on Nissan RB26DETT
Similar Turbo for no particular engine.

I expect that something like the GT2860 series would be appropriate for a 13b with minor mods. But i hear of allot of people running GT35's .

I used Garrett for the example because they have nice compressor maps posted. I have seen many other turbos with various sizes and shapes on the compressor maps and i have not spent enough time looking at them to know exactly what one will work best with a 13b of any particular configuration.

 

Ted's site has some good general info on turbo sizing for the 13b: http://fc3spro.com/TECH/TURBO/compmap.html

Also, that ebay turbo has a 0.63 AR hotside which is way too small for a rotary. The stock turbo has a 1.0 AR for reference. Compare it (T04E 57 trim) to some of the others listed on the page above. It thrives above 15 psi, while others are more suited towards lower pressures.

Then of course, you'll need bigger injectors and a standalone to control it all.

 

The problem with T25 hotsides and all but the largest T3 hotsides is that they result in a lot of backpressure which kills power and raises exhaust temps. Rotary engines need more fuel and more turbo to than a piston motor does to make a similar amount of target power.

well it's .63 T3 hotside. If it were a similar sized T4 (with T4 turbine wheel), it would still be small but wouldn't choke it nearly as much.

 

Yeah, and the stock turbo turbine wheel and housing would be essentially T4 sized, right? Obviously the flange isn't T4, but just sizing wise.

 

just from my own comparisons I'd say it's much closer to a T3 in terms of flange size--certainly not a T25, but too small for a T4. The stock turbine wheel as I have mentioned in other threads is almost exactly the same as a T3 stage II wheel at least in its dimensions.

I'm not exactly sure how the idea came about that the stock turbine housing A/R is 1.00 . I mean I guess if you compare it to a Garrett T3 housing it is probably close to a 1.00 equivalent. But actually calculating the area of a turbine housing with some precision would require you to use integrals because of its shape. Now actual Garrett engineers, like most engineers in the real world, probably have a simplified formula for calculating housing area (and from there, the A/R). That simplified formula was probably derived using integrals.

The ebay turbo posted in this thread though really isn't much bigger than stock in terms of the turbine housing and wheel, so it's kind of pointless to get when you can just get a hybrid.

 

I've actually measured the dimensions on the stock turbo's turbine housing and done the calculations for A/R myself. It came out to 1.06 IIRC, and I used approximation to get close estimates of the area of each port. A rectangle with four small triangles worth of area subtracted off for each. The ports don't have that much curve to them anyway; they're fairly angular. All measurements were taken with digital calipers, so it should be pretty close to the actual number.

 

Wow... Most if not all of the last three posts went way over my head. I'm understanding that the exhaust, (or hot side?) or the stock turbo is 1.00 in size. What does that mean? Also, I see a bunch of turbos with t88 or what ever listed and such. What does that mean? I think I need to learn to speak turbo before I think about upgrading it.

I know how they work, I just don't understand how to read about two and know the difference between them.

Sorry, I told you I was a newby

Thanks again,
Scott

 

I'm reading that link you sent me RotaryRocket88, things are STARTING to make sense. After I read that I think I'll be able to interpret what captan mike posted. And, after that I think I'll have a lot of questions... Lol.

 

Alright, after reading a bit I'm going to pretend to be educated and set my sights on one of these two turbos. I'm wanting to run between 1.75 and 2 bar... Not sure yet but yeah.

http://cgi.ebay.com/ebaymotors/ws/eB...K%3AMEWAX%3AIT
This one I'm not sure about because I don't know which chart to look up for it. Lol, ignorance is bliss.

http://cgi.ebay.com/ebaymotors/ws/eB...K%3AMEWAX%3AIT
This one I know is good for my application due to the awesome chart!! Yay charts! I feel like a kid in a candy store.

 

Best tip: If you don't know what you are doing, let a professional choose your setup based on your performance goals and budget. While the internet is a great resource, I do not recommend basing $1,000+ decisions on what you read here.

Other tips that aren't so great:
- You get what you pay for. Cheap Ebay turbos are made in China, Mexico, or some other place with horrid manufacturing skills. Some Ebay turbos have been literally glued together. Name-brand turbos from Garrett, Turbonetics, Holset, HKS, GReddy, etc., are far superior. The Garrett GT-R turbos are considered top of the line. Buying directly from the manufacturer (Garrett, Turbonetics, Holset, etc.) is usually cheaper than buying from a flashy re-seller (HKS, GReddy, etc.).
- Oil-cooled turbos were outdated about 20 years ago. Modern turbos have connections for both oil and water coolant. Only noobs buy oil-cooled turbos nowadays.
- Beware of hidden costs. While you have identified that an external wastegate may be required for some turbo upgrades, there are other upgrade issues such as downpipe, fuel injectors, fuel computer, fuel pressure regulator, fuel filter, fuel pump, fuel lines, fuel rails, oil and coolant lines, fuel cut defenser, boost gauge, blow-off valve, intercooler, turbo manifold, air filter, etc. A turbo upgrade can cost over $10,000. To avoid this problem, see "Best tip" above.
- There is no reason to waste your time and money on a single T3 turbo. If you want something simple and cheap, just get one of the BNR upgrades. Otherwise, step up to a proper T4 turbo.
http://www.bnrturbos.com/2ndGen.htm

That is the Area/Radius ratio of the turbine scroll, which is basically the aspect ratio of the nozzle feeding the turbine. The important thing to know about this statistic is that it is relative to a given turbo, so you pretty much only concern yourself with it AFTER you have selected the compressor size. See "A/R" in this link:
http://www.turbobygarrett.com/turbob...o_tech102.html

It is the model designation of the turbo, which is loosely based on size of the turbo. Unfortunately, each vendor uses a different designation code.
http://www.ztechz.net/id4.html

 

I've a proffesional mechanic that I can get to help me out with all of this in general, but I really want to get my hands dirty. 3/4 of the reason I'm working on upgrading and such is so that I can learn. I'm a hands on / lecture learner and at the moment schools out so I can't really do much for lecture.

As far as the E-Bay turbo goes, I should've specified that I was thinking about something that size... Looking back... I had no idea what size it really even was lol. (Yes, I actually laughed at my ignorance.)

As to the hidden costs, I've upgraded to a Walboro 255 I've a Greddy type S BOV attatched to a cheapo e-bay fmic. So that leaves the larger injectors, and a better fuel pressure regulator along with the rest of the turbo set up correct?

Thank you for the link to the BNR stuff!! I'd heard a lot about them but couldn't find anything actually tangeble on them, to me they were a myth. Showing me that link, aside from the anti-fuel cut off switch for my stock ECU, (Want to move to Haltech eventually probably in the next two or three months.) The BNR would only need the fuel injectors / pressure reg. right?

 

Be careful with who you consider a professional. Just because someone is a super tuner on a honda dose not mean they know anything about your engine.

I had one professional recommended that i upgrade to a smaller turbo because he had no idea how big the stock turbo was.

Another professionals jaw dropped when he saw the hot side of the stock turbo.

The best thing to do is take ever recommendation you can find research all of them. filter out the crap, then do some figuring. Unless you want an exact copy of someone's car, or you want a car your going to need to see what other successful mods you likes and mix and match to make it the way you want.

Garrett has many pages of general turbo info starting with the basics. might be a good place to start reading.

 

Contact Bryan@BNR to see what he recommends.
https://www.rx7club.com/members/bryan%40bnr-72684/

 

The proffesional tech that I trust is the local Rotary Engine rebuilder. He's got about 40 rebuilds under his belt.

His RX is pretty sick, but I appreciate the advice Captan Mike if it wasn't for the local Rotary Club I'm sure I would've ended up with one of the techies you mentioned.