1234rotor

iTrader: (1)

Woo Hoo! I am too excited. My original twins have 89K miles on them now and are smoking when cold. I will hopefully be installing these in the next month or so. I am going to ceramicoat the manifold I think, and keep them full sequential for my 320whp goal.

I figured I would ask if it might help me some to port the main wastegate flapper a little bit. I will be running ball and spring MBC"S on this set-up. I plan on pushing no more than 13.5psi on these turbos. They are supposed to be 2002 models w/ approx. 10K on them

Heres some pics:

1234rotor

iTrader: (1)

One more pic....

jeffrored92

I want some new turbos.

How much did they set you back?

You're gonna have some fun

widebody2

Sorry to be such a hater but I read this here on the forum and pretty much can't disagree with one word of it. It was originally posted by highspeed:
" The 99s make less power at the same boost on an rx7 in the US. I'll explain it all right now. 99 rx7 = 280 fwhp 93 US rx7 = 255 fwhp. So thats a 25 fwhp difference....lets convert that to whp since thats what most people use when talking HP. 25 - 15% drive train loss = 21.25 whp more for the 99 japanese rx7. Now a 21.25 whp difference is significant, but none of that is due to the turbos being different...in fact you'd make more with US spec twins. Here's why: There are many other differences between the US and japanese 7s than just the turbos. A few of them that effect HP #s are 1) 99 rx7s run 2 lbs of boost more. Thats an easy 15 hp, if not much more. 2) The 99 rx7 has no precat, instead they use a nice down pipe just like our aftermarket ones. Thats another easy 10 hp. 3)They also have the efini Y-pipe which flows better than ours. Thats another supposed 1-3 hp. 4) They also have no emmisions equipment on their manifolds, which makes them flow better. Tack on another .5-1 hp.
So if you add all that up...even on the low side its 26.5 whp. The 99 rx7 only made 21.25 more whp than a 93. All my estimates were even low..usually people estimate 1 lb of boost in a turbos efficiency range would = 15 hp. I only made it 7.5 hp. This all makes sense when you consider that the 99 turbos use a smaller compressor wheel in order to boost sooner. I would say power wise that the 99 spec turbos are a nice little power down grade actually. They do spool faster though. "

SpeedKing

iTrader: (4)

From rx7.net.nz:

"The new power is achieved with a little more boost from the new turbos.

Previous standard boost was 9.08 psi (0.62 bar) now we have 10.82 psi (.746 bar)."

1234rotor

iTrader: (1)

AND ALSO....

Most people were claiming that the 280hp fd's were really making around 310 hp stock. I would totally believe it too.

It is claimed that the skylines have been making 350+ stock, yet were still rated at 280hp also.

Honestly I wouldn't doubt that these turbos flow just as well if not better cfm per psi than the pre 99' 255hp turbos. I am guessing that the research and effort that went into changing the blade angles and making the abraidable housings would be worth the effort. As far as I know, these turbos spool quicker and boost more efficiently, which in turn could even lead to more cfm per psi and rpm. It may also bring down the heat,from being more efficient.

I would have much rather had a set of BNR's, and saw some for $1100 right after I purchased these, but I am sure these will be more than enough for my driveability and horsepower needs.

jeffrored92

Mazda engineers claimed increased flow characteristics based on the following:

Note the referenced power increase is from the series-7 version, not the series-6 which most of you in the US have.

1234rotor is right with the increased flow at a given psi, and that is a direct comparison between the turbo's themselves. Swapping out the 93spec for some 99spec turbos, and operating them at the same boost level "should" provide an increase in flow, which you would imagine would yield a power gain.

widebody2

It is just like mazda to under rate power on their cars...just look at the rx8....RIGHT...

eyecandy

iTrader: (19)

It was Mazda USA that screwed it up, the rest of the world had it right at 238 HP. I saw that coming form a mile away....

ptrhahn

iTrader: (9)

I was a big doubter of these turbos, until I happened on a VERY good deal for some, and installed them. The outright peak power may not be much greater, but the overall characteristics are. I've got a ported motor, with a fully open exhaust, and these build boost almost like the car did when it was stock... and more importantly, according to the specs i've seen, they are more EFFICIENT at higher boost levels, AND the wastegate doesn't need porting, so I can actually run the open exhaust and 15 psi with no worries.

My car is QUICK now.... giving small singles, and alot of high-dollar machinery a run. I would estimate it at about 360-370 rwhp @ 14.5 psi

I don't know that I would have paid $3,000 for them, but they bolted right up with all of my existing infrastructure, and haul ***.... i'm always up for a benchmark run....

ptrhahn

iTrader: (9)

I think the point is that Mazda felt ABLE to run that higher boost level, because the turbos are more efficient, producing less heat etc.

DaleClark

iTrader: (55)

Personally, I'd love to have a set of '99 twins. It fits right in with what my goals are for the car - low boost, stock twins, just a "refined" stock setup.

From what I've heard from across the pond, the "low power" turbos are actually more popular if you want to run a lot of boost. The 280hp turbos aren't as reliable at higher speeds/ more boost - I think "high boost" here being at or over 1 bar.

But, if you're staying more conservative, it's hard to beat quicker spool and lower air temps.

Dale

PVerdieck

Bad example.

All the Japanese manufactures have been listing 280 hp because that is/was the law. Its well known that some models of their higher end performance cars exceed this, but the manufacturers aren't stupid enough to advertise their skirting of the law. The later FDs were evolving as a result of changes made to keep the car competitive and on top at Bathurst, which was not the case with the 1st generation Renesis engine in the RX-8.

saxyman990

It was never an official law, just a "gentleman's agreement."

-Rob

saxyman990

BTW, I'm in the exact same position as ptrhahn. I got a killer deal on my set of 99's. I absolutely love them! Perfect for what I was looking for.

powermalex

1234Rotor

I got my 99 Spec Efini twins from RX7.com. Just wondering why yours is all apart.
Also my stock twins ran fine other than the oil leak. I had a bad 2nd turbo seal. The pattern I had with the stocks TT were 13-10-13. The pattern with the new is 17-13-17. I had a significant HP gain but at same time overboosting as my M2 Stage 3 ECU upgrade and injectors and fuel pump were probably at there peak. Also with in <25 miles I blew the front cover seal because of a bad PVC valve. Now I'm installing larger injectors, Power FC, higher fuel pump, replacing front cover seal with metal type and hopfully get hold of a new Pineappleracing cast oil pan. After that I need to upgrade the clutch assembly. I hope to get >300HP at the wheels.

Food for thought all this because I just wanted to fix a oil leak. So the new twins caused a chain reaction. I love the way the twins work you definatly feel both surges of power.

Good Luck.

widebody2

Man I hate being a stickler but I'm pretty sure the supras, 3000gts and 300zxs were all above that magic 280hp mark...anyway there definitely is some situation with the 280 hp since the 20bs were detuned to make that power. I was actually kind of just being a sarcastic ***** with the rx8 comment. I'm sure the 99+s are nice if thats the type of thing you are looking for...but honestly in my opinion anyone who actually pays the full $2400+ for these things is nuts. I'd also love to see some dyno proof of the stock 99+ rx7s having 310 hp or so...I REALLY don't think so.

Jonesboro

It looks like you have abraidable turbos but I thought that 99 Spec turbos had a N3G1 serial #. Check this thread:


https://www.rx7club.com/showthread.p...ght=spec+turbos

1234rotor

iTrader: (1)

Well, I can tell these turbos have hardly been used, and he said they were from a 2002 model. Maybe there was a different number on the very late models???

I guess I have Spirit-R turbos... that is all they made in 2002.... CORRECT??

Jonesboro

The correct Mazda part numbers for 280 HP turbos were provided in a post towards the end of this thread:

https://www.rx7club.com/forum/showthread.php?t=403231

I don't have an explanation for why your numbers are so different.

jimlab

Actually, the 280ps (1 ps or pferdestärke = 0.986 US horsepower) "limit" has/had nothing to do with any law, nor were engines "detuned" to make a maximum of 280ps by law as other rumors have stated.

Cars obviously making more power (Skyline, Supra, etc.) were simply underrated at 280ps for insurance reasons, very similar to what was done with muscle cars in the 60s and very early 70s. For example, the 1969 Ford Mustang Mach I with a 428 was rated at only 355 horsepower, but actually made somewhere around 400. Another example is the 427 CID L88 that was available in only a handful of Corvettes from 1967-1969. It was rated at 430 bhp, but according to most sources and dyno tests, actually put out somewhere around 560.

HDP

iTrader: (2)

If you look closely at the "one more pic" in 1234's 2nd post, you will see the N3G1 number. It's always stamped on the secondary compressor housing.