REW Twins Question - Efini
 

Do any of you have any experience with the Efini 99-02 Twins??

On the website www.rx7.com you cant miss em. The site says that 330 up to 385 WHP is possible. Does anyone know if this is true or not first hand?

Is This a good way to make 440 Flywheel HP or 350WHP sequentially? I just want to know if the turbos are capable? Because I found some damn near new ones for sale locally. Ill handle the tuning aspect when I get there.

*YOU DONT HAVE TO READ THE REST* (mainly ramblings, and why I want to know)

Whats interesting is the stock HP rating for a series 8 rx7 was 280 So these must not be factory turbos, yet it says 'fresh from the factory' Perhaps they meant the upgrade factory?

My friend at work has a 570 HP Mustang hes building, and clowns so much on 7's you wouldn't beleive it. So were going to the track around summertime, needless to say. I was running some numbers and found that Ill actually need 350WHP to win by a little. (Going in my 1st Gen) With all his torque, Id imagine hed beat me off the line, but I should be able to pass at high rpms.

I'm starting an entire rebuild probally next week. After I bought the REW motor, I found that some of the apex seals were stuck in the rotors. Yes I tried to free them up. Fortunately everything else you can see through the exhaust port with a flashlight looks brand new. The motor must have sat a long time. So who knows what else is frozen or where there may be weak seals/gasgets. Plus my turbos have a little shaft play, not bad. But to ensure a good engine, Im going all out. Do it right the 1st time.
Im sure Ill have more questions along the way, but Ill save those for later threads :)

The Efini Turbos are basically the same as the '93-95 turbos. When I mean basically, I mean you can change them in and out and never really notice a difference.

The later RX-7's had a bump in the stock boost (up to 11 PSI instead of 10 PSI), as well as the slightly higher flowing Y-pipe. That is what gave them 280 PS, not really the turbos.

People generally go with the Efini's when they want "brand new" stock turbos (as you can usually get the Efini's cheaper than the real 93-95 stock turbos new).

There are performance differences, all else being equal. The 99 twins have a 'better' compressor map due to the close-fit abadable seals. It keeps intake temps down a little bit compared to the 93-95s, and if you decide to push the boost it will be a noticeable difference.

However, the efinis are pretty expensive if you're going for performance. For performance, the BNRs or a small single offer a much better bang for the buck.

Dave

I'm guessing you're looking at putting this motor in an FB? If you're going custom, I'd go with a single turbo. You won't have to try and get the sequential system to work, and good-sized singles can make some really impressive horsepower.

Dale

I'm running them on my car. With a street ported motor, 1300cc secondaries, full exhaust, IC, good tuning and other supporting mods I made ~350 Rwhp running sequentially at 14-15psi.

They are indeed factory turbos built by Hitachi for Mazda. The design differs slightly from the 93-95 turbos. You can do a search for the specifics or just give the guys at RX7.com a call. I've always found them very good to work with.

If you're looking for bigger power potential, the BNR turbos running sequentially will work also. Look for Rynberg's dyno with those. Goodfellafd3s had the BNRs running non-seq and a longer list of mods (fuel, tuning, etc etc) and made big frickin power (over 400) but Non-seq always results in more lag.

its not worth it IMO to go with 99twins. if you keep the twins you should check out the BNR's they're cheaper i believe and they make more power. but if you wanna destroy him. go single.

i have 99 twins. the spool faster than stock twins. imo at least. never owned a rx7 with stock twins to fully compare with, just a friend who has them.

yea you can find many nice single turbo kits for about the same as the BNRs and 99 spec. bu then you;ll have to spend more on the fuel system and such. I'd go single.

^ +1, if that is your intent, slayerx7. With all the time you will spend possibly troubleshooting the stock sequential system, you can easily get more top end power working with a single turbo setup.

U see u learn something new every day i didnt even know that word is real , let alone it actually does something

<< noob. Can't find a definition for "abadable" anywhere.

It's "abradable".

that makes some sense. So the blades actually shave out the housing? How does that work?

BNR's plain and simple.........if you want a twin setup

WOW! I must say Im impressed with all the responses 24 hours later.

I am going to look at the BNR twins and compare.

To answer a couple questions that came up:

1. Yes its my intent to put the REW in my 1st gen, it will be entirely custom Im sure.

2. I want to go with a sequential set up.

*WHERE IM COMING FROM:*
I may do a single turbo set up in the far future, with a different car, but for right now, the virtual no lag, power on tap sounds very appealing. Also learning the sequential set up right off the bat must be amazing. From what I hear, If I have a thourough understanding of the sequential set up, then doing anything else (in life) should be easier.

Thanks Brazer7 for telling me its possible, and everyone that reccommended BNR. At first my goal was a 12 second car. Then I learned that low 11's wasnt going to be much more than Im spending anyway. (Where my goal for 350WHP came from) Ill be perfectally happy with that, but Im starting to wonder If I should spend a little more to get into 10's.

But 10's may bring reliability issues

I intend for this car to be decently reliable, and BE ABLE to drive it up to a couple hundred miles a week, not that I will be; just to have the ability. Or even random road trips. I want this motor to last about 50,000+ miles before a rebuild. Yes I baby my car (Early oil changes, warm up/cool down 5 min at a time, stay off the throttle till the car reaches normal temp. Synthetic gear lube, ect)

Thanks for all the single info, Esentially it seems that its more bang for the buck AND easier to deal with. Which may very well may be a better way to go, and explain all the single turbo swaps out there. But Im set on doing this sequential

My goal for this is everything for $15,000 (minus wheels/tires/paint. ect ect.)

I dont intend to sell the car ever, but if I have to, I know I wont make my money back, and hey Im ok with that, because it will have been worth it :)

having dealt with the sequential setup as much as i have, my personal opinion is to go with a single turbo. if you want super quick response just get a small-medium sized turbo and you'll have plenty of both power and response to suit your needs.

It's got a plastic lining in the compressor housings that the compressor blades can safely rub against. This allows closer clearances and higher compressor efficiency.

Okay, so i take it the small tolerance of plastic that the blades can rub against is small enough not to be a problem in the exhaust system? If this is on oem hitachi turbos why isn't it popular in the aftermarket?

The plastic is soft and not brittle, so it can shave away easily without stressing the blades and the bits that come off come off clean without leaving jagged edges. The clearancing to the plastic is done before they are in the consumer hands but the idea is that the plastic is of such a small stress that it can literally touch the blades, offering a 0 tolerance seal without causing damage.

Personally I like the upgraded stock twins in sequential form (BNR has some amazing input on this) but for a car that wont see many mods but is after reliable horsepower for daily driving, I'd say the abradable seal version are a good way to go.

_Kris

IMHO, the sequential setup is a pain when you're 1) trying to diagnose it without taking too much stuff apart and 2) leaving in the emissions stuff. You won't have that problem.

If you simply buy 2 low mileage solenoid racks and a good Mityvac tester, you can go thru the solenoids and test them. Sort out the good ones, and throw the rest away. Now use decent silicone line and put it together per the vacuum line chart. Install a pressure regulator on the pressure tank, manual or electronic boost controller and you're set to run higher boost on the sequentials.

With a set of BNRs, you'll make a lot of HP with minimal fabbing. It won't run as cool as a small single, but you'll get that super broad power band. The BNRs beat the 99 specs in power and value, hands down, especially above 12psi.

I still think a small single would be very responsive and most reliable.

Dave

but with that kind of power horizon wouldn't it drop off sooner? what small single @ about 350hp peak isn't going to run out of breath at 7k or earlier?

i'm looking at sequential bnr's but i need to convert my non sequentials back to oem or simplified form before i make that decision for sure. (i never had sequentials)

All small singles or non-sequential turbos will do that. That's a given.

When it comes down to performance, any single will produce a broad enough powerband to get thru even the widest shift points. Having even broader torque curve is cool and all, but when it comes to going fast any good driver operates in a 2-3k rpm range.

Dave

fwiw, i know of a few people that have run 12s on stock turbos and stock ports. I'm not a drag racer so I don't know how good or bad or regular that is.


NissanCon - by small turbos I think dgeesman is referring to something like the old GT35/40 which was based on a T3 foot print. Friend of mine is running a T04 and easily made high 300s and low 400s with an ebay manifold and stock ports. IIRC the low 400s was a bit of a fluke as it was during a boost spike in the high teens. Wasn't planned :)

I was looking at the 3540 for an old project. Usually when I engage in speed of questionable legality i run the car up to 6-7k because my poor man's don't give me the good boost until 3500-4000.

In fact, I know it may be against my better judgement than to go with a sequential set up, but after researching this, it seems the BNR's are exactly what I want. Even is a single is flat out better. Im stubborn dammit! kinda funny cause I didnt even know they existed 48 hours ago :D

Has anyone ran 2 intercoolers? Im thinking about it, but Im sure they make single ones that can handle both nicely. Just a thought to keep temps down better. And definately will be getting a serious radiator.