With all this talk of \'99 spec\' turbo\'s, and people potentially spending lots of money \'thinking\' they are buying a super turbo set up please read this and if you can prove me wrong PLEASE do so !
From things l read when the 99 car was released the only difference was the use of better metal used for the blades !
As for making more power the inlets are the same size as all other 3rd Gen cars, as are all the other parts that bolt to the turbo pack, so if it aint passing more air l fail to see how you can produce more power, unless they altered the blade angle, but l have never seen anything written about this, and this would only give a slight HP increase .
( at this point please note that even if there were a difference you would need to strip the pack off to tell!)
Lastly l have just compared part numbers from my year 2000 parts book across to the 1993 part numbers and found NO difference.
Its also worth a mention that a rumour went around a while ago that the \'99 spec\' engine had different internal\'s, it has NOT, this is a fact from matching all the part numbers inside the engine.
The 3rd Gen RX-7 engine remained untouched from the start of its production till the end as did the clutch, gear box and differential, with power increases coming from its electrical components NOT its mechanical ones.
As l said if you know different tell me, but in my opinion the fabled \'99 spec\' parts are at best \'pub\' talk and at worst a way of sellers hiking the price .
Sorry if this has dampened peoples fireworks!
I thought that the 99 turbos had self abrading blades or something like that.
Don\'t have them myself and doubt i\'ll ever get them either!
A link with some comments on the overall improvements to the 99-02 RX7s.
Power increase comes from a range of improvements. Turbos were "enhanced" a little from the earlier ones with some minor modifications.
http://me.a-spec.ca:6001/Present/99RX7.html
would someon post a synopsis of the url - it\'s not on the standard web port and is blocked by most work-place firewalls...
Iain
main chunk of text from site:
Mazda\'s rotary engine production is at most a few hundred units a month, a fraction of what it used to be in the heyday of the Hiroshima-based company\'s ambitious "rotarization" movement. The rotary engine is alive in Japan, kicking harder than ever in the face-lifted and improved RX-7 sports car.
Major improvement to the new \'99 Mazda RX-7 is the retuned motor with 280HP. Low down torque has been sacrificed for high end power. There is much less turbo lag and loss of low down torque isn\'t a problem. The rear might be light when going through long fast corners or down hill corners. This cornering problem is solved by adjusting the new adjustable rear wing up two notches, giving more down force in the rear. The new rear wing was made because the RX-7 is aerodynamically critical due to its light weight. The wing is adjustable to create down force and also gives a spoiling effect to reduce drag.
ANGLE OF ATTACK FRONT DOWN FORCE REDRAWN FORCE
1 ° 0.045 0
5 ° 0.047 -0.025
10 ° 0.051 -0.058
14.5 ° 0.053 -0.075
Bigger front lip, on the old FD a front lip air dam was fitted to the Type R and available on other models as an option. Due to the huge openings in the front of the New FD, the volume of air entering at speed could not pass through the radiator fast enough and was coming back out again. This excess air was then flowing under the car, reducing the negative pressure and unsticking the car from the road. To combat this problem a much larger lip was added to the bottom of the front spoiler and extended to carry any excess air around to the sides of the car. The lip also extends further forward and collects air from the in front of the car, further reducing the pressure under the car, increasing down force.
The RX-7 is a very unique car because nowadays there are many kinds of traction control and VSC and the RX-7 is the only real sports car that doesn\'t use any electronic device, Traction Control, Stability Control, 4WD, 4WS ... etc. Mazda\'s Rotary Engine is still the only unique engine in the sports car market. This was a big advantage years ago but now other engines have caught up and the rotary\'s light weight and the power advantage is getting reduced.
Air flow through the engine compartment has been changed to reduce temperatures which has been thought to create premature turbo failures. Radiator front duct entrance is 2.5 times bigger than before. Oil cooler ducting is 1.8 times bigger and intercooler duct is also 1.8 times bigger.
Turbo boost is up from 0.62 bar (9.08 psi) to 0.746 bar (10.82psi) by using a new exhaust with less back pressure and higher flow turbos. The turbos now have an abradable seal. The clearance between the compressor wheel and housing is zero. The compressor wheel rubs against the snail all the time. The compressor wheel diameters have been reduced from 51mm to 50mm so they will spool up quicker (less lag). Over two (2 kg) were removed from the front by changing the radiator ( while it was increased by 2mm in thikness ) duct and electric fan, this has improved handling and recompensated for the added weight of the spoilers. Power to weight ratio is now 4.57 kg/hp (fastest car Mazda has ever produced). Suspension has been retuned to increase road holding on winding roads.
ITEM WEIGHT LOST
16" wheels -0.45 kg each
Radiator Fan -0.80 kg
Steering wheel -0.23 kg
Front bumper reinforcement -0.40 kg
Radiator / intercooler duct -0.15 kg
Front number plate holder -0.20 kg
Front side reflector -0.14 kg
Leather seats are gone, the doors lost their tinny clunk, when shut, in favor of a more solid thud. Bigger 17" wheels for the RS-R and the brakes are bigger by 1". A knee pad attached to the door and an elbow pad replacing the ashtray. The new model also has the much needed boost guage (measured in mm of mercury) that replaced the oil pressure guage. The tach is turned a little so 6000 rpm is at 12. There is now a Nardi steering wheel. No more side lights in front of the front wheels. The Y-pipe from the turbos is an aluminum like in the 1992 13B-RE Cosmo and there is new plastic pipes for the inter cooler and air box.
1998. 12 : The RX-7 have gotten the 280PS. Enhanced turbocharger efficiency and cooling performance due to increased air-intake allows the RX-7 to achieve a maximum engine power of 280PS (Type RS and Type R) increased engine power combined with the light weight of the type R model realizes a power-to-weight ratio of 4.5kg/PS. The type RS adopted single-cylinder dampers jointly developed with BILSTEIN of Germany.
2000.10 : The limited edition RX-7 Type RZ is equipped with red custom full bucket seats manufactured by RECARO, a customs suspension system manufactured by BILSTEIN, and custom alloy wheels manufactured by BBS. These and other enhancements reduce the overall weight of the Type RZ by approximately 10kg, improving handling and performance.
2001.01 : The new special edition Type R Bathurst was based on the Type R, the RX-7 with the lightest power-weight ratio. It is equipped with custom height adjustable dampers and fog lamps. The name BATHURST was chosen to commemorate the Bathurst 12-hour car race in Australia, where the RX-7 was victorious for three consecutive years (1992-1994). ( link,
2002.3 : As the final limited-production series of the RX-7, the Spirit R series was introduced in Japan. The Spirit R Type-A is a two-seater model fitted with the Recaro-made exclusive red full bucket seats. All three models are equipped with common interior and exterior features, such as BBS 17 inch wheels, red brake calipers, and interior panels with a special soft coating, while each model shows off its own equipment to make a difference from the other
Hi Clive,
The 99 spec turbo\'s are better than the earlier ones in that the tolerances are much closer and tighter particularly on the compressor housings,this is due to them being self abradable which means the compressor wheels actually wear the abradable surface in the compressor housing when new which means a much more efficient design.The main advantage of this is that there is less heat and turbulance generated at higher boost levels.
Also the ecu has a map in it that can sustain the higher power output of 280hp for the top model.
The engine did have some minor changes but not any that would make more power.The housings are the same.The rotors are the same.The seals are the same.
The differential on these cars is also different.
Kind regards
Carl
I don\'t pretend to know the answer but this site claims there are differences, at least on the 280bhp models:
http://www.rx7.net.nz/rx7netindex.html
Extract of relevant bits:
Now Mazda has joined the 280-bhp club. The latest 13B-REW produces 209 kW (280 bhp) at 6500 rpm, an increase of 11 to 13 kW (15 to 18 bhp) obtained above 5000 rpm. Torque output is also improved by 20 Nm (15 lb. ft.) in the critical mid-speed range above 2500 rpm, peaking at 314 Nm (231 lb. ft.) at 5000 rpm. New turbochargers, improved apex seal lubrication, freer exhaust, enhanced cooling, and more elaborate engine management are cited as bringing these benefits, while the engine\'s internals are inherited from the previous version.
The turbocharger, two of which are used in the sequential setup, is a new Hitachi instrument with an abradable compressor sealing and an "ultra-high-flow" turbine design. The abradable compressor housing sealing has been in U.S. markets, Toyota being the first to use it in the MR-2 sports car, some years ago. It was one of the more promising items in the menu the Mazda\'s rotary engine designers had prepared a few years ago to get more power out of the 13B-REW, but, according to Yamamoto, the company was
in a dire financial state, and the design team could not dare ask for the expensive turbocharger. The Toyota unit had plastic layer hot-sprayed onto the housing\'s surface, a methodology hardly suitable for large scale production, therefore costly.
Hitachi has since come up with a new built-up construction of the compressor housing. A formed plastic inner sealing element is bolted onto the main housing, and then machined. The turbocharger is assembled, and run up to 100,000 rpm, abrading the inner surface of the plastic seal, obtaining the closest clearance between the compressor and housing. The new abradable turbocharger has an 80%-plus efficiency, whereas a typical instrument\'s efficiency is about 75%, according to a Mazda designer. This brings down
the compressed air\'s temperature by 10 C, or about 10%, at the exit of the compressor. Air temperature is still in the region of 110 C (230 F), which is further cooled down by the air-to-air intercooler in the RX-7
installation.
The latest trend in high-performance turbo technology is a "diagonal flow" turbine. Mazda asked Hitachi to come up with several candidates of this design, hoping it would boost the engine\'s output. They did not quite match the rotating piston engine\'s unique characteristics. Back to the tube, as it were, to research basic flow dynamics. The fruit of the toil is the "ultra-high-flow" turbine, with its blade length extended and its shapeless acutely curved, enlarging gas passage and reducing flow resistance. Turbo response in the low speed zone has been greatly improved. The turbocharger adopts a smaller diameter turbine, 50 mm (1.9 in.) now versus the previous unit\'s 51 mm (2.0 in.), again reducing inertia mass. The new
"ultra-high-flow" turbine realizes about a 10% gain in efficiency, according to Mazda\'s turbo engineer. The twin ultra-high-flow turbochargers supply a maximum boost of 74.7 kPa (10.8 psi) at 6500 rpm to the previous high-flow instruments\' 62.7 kPa (9.1 psi) at the same rpm.
Thanks for the info guys.
Carl,
Do the 265bhp \'99s have the newer turbo specs?
Thanks
Kevin
Thanks guys,
Some very interesting and informative reading there, i notice that in the specs of the engine, the 13b is rated at
1308 CC, i still dont understand why in this country this is jumped up to 2-6! also i dont understand why some RX7s are taxed as
1-3, but most appear to be classed as 2-6! but my insurance company reckons its a 2-3! can anyone clarify this please? also, with the above manufacturers specs, would this not be proof for DVLC that they should rate these cars as a 1300cc? can anything be done to clarify this to DVLC?
Bob
I have a thread on this somewhere on here already listing all the differences between the 99 onwards cars and the rest. Should of been made a sticky. Also the exhaust system has 10% less back pressure.
QuoteOriginally posted by ro284
Thanks guys,
Some very interesting and informative reading there, i notice that in the specs of the engine, the 13b is rated at
1308 CC, i still dont understand why in this country this is jumped up to 2-6! also i dont understand why some RX7s are taxed as
1-3, but most appear to be classed as 2-6! but my insurance company reckons its a 2-3! can anyone clarify this please? also, with the above manufacturers specs, would this not be proof for DVLC that they should rate these cars as a 1300cc? can anything be done to clarify this to DVLC?
Bob
Huge thread about the tax thing here:
http://www.mazdarotaryclub.com/forums/showthread.php?s=&threadid=4041&perpage=15&highlight=tax&pagenumber=1
If the insurance company says you are insured as a 2.3 (assuming you have a 3rd Gen), then you maybe wrongly insured! The 2.3 was the 2nd Gen...the 3rd Gen has never been a 2.3! You ought to really double check and get the insurance to change your details. Worst case scenario is....accident...try and claim...."Sorry Mate, you\'re insurance is invalid \'cos you\'ve insured the wrong car". Any insurance company that says my car is a 2.3, and not a 2.6, I walk away from. There is no way I want to give them any opportunity to not pay out if I every did have an accident.
Thanks Andrew,
Iwill change details with my insurance company for my 3rd gen RX7, i have to tell them it is a 2616 cc, but it is in fact a 1300 cc!
Thanks again Bob
The 1.3 vs 2.6 argument has been raging for years. Mazda apparently agreed to classify it as a 2.6 (or 2.3 for the earlier ones) for whatever reason, and this has stuck ever since. some kind of deal between Mazda and the DVLA...not sure of the details. Stupid really, since even the brochure for the UK cars said it was a 1308 cc, yet the manufacturer tells the licensing authority it is 2616. Shame they have never made the effort to rectify this and clear it up once and for all. But since there are various mechanical arguments to justify both 1.3 and 2.6, it will never be sorted. Some lucky owners do manage to register it as a 1.3, but that must really affect the insurance, \'cos of all the insurers I\'ve every talked to, never have a 1.3 RX7 avavilable on their books. But someone must, though, just not sure who!!
1.3 vs 2.6 argument...
Each rotor face displaces 654cc, 6 rotor faces firing every revolution = 6 * 654 = 3926cc. But, due to a 1:3 gearing on the output shaft (i.e. at 9k rpm the rotors are doing 3k rpm), each rotation of the rotor housing produces 3 rotations of the output shaft (crank):
(disp * rotor faces) / output gearing = disp/rpm
(654 * 6) / 3 = 1308cc
Comparing this to a 6 cylinder piston engine with a displacement of 2.6l 3 pistons fire each revolution of the output shaft
disp per piston * pistons per rev = disp per rev
(2600/6) * 3 = 1300cc
So we are directly equivalent to a 2.6l engine in displacement terms.
Iain
nice one iain that makes things more clear for us...
Still doesnt explain why they classified the 2nd Gen as a 2.3!!!
that had a 13b engine as well!!
How many threads actually keep on the original subject?! Its funny how the conversations sometimes drift so quickly!:rollin
QuoteStill doesnt explain why they classified the 2nd Gen as a 2.3!!!
Damn, someone got there first! I was going to ask that!
Right, Lets bring this back on track! ;)
\'99 spec turbos!
Are they worth it?
Must be worth it, if Mazda invested in them! But I guess that is inconjunction with the other tweaks Mazda carried out to give the later cars better drivability and slight raises in power. The later cars were a "package" of improvements, not just a simply swap one turbo pack for another. I guess just one their own, they would not really do alot!
I suppose same argument with a single turbo - on its own, is it worth it? No....but together with all the other mods ...... then yes, if thats what you want!