Go Back   Rotary Car Club > Tech Discussion > RX-7 2nd Gen Specific (1986-92)

RX-7 2nd Gen Specific (1986-92) RX-7 1986-92 Discussion including performance modifications and technical support sections.

Reply
 
Thread Tools Display Modes
Old 02-20-2010, 07:42 PM   #1
Justen
In Too Deep
 
Justen's Avatar
 
Join Date: Jun 2009
Location: Clifton, NJ
iTrader: (3)
Posts: 112
Rep Power: 16
Justen is on a distinguished road
Default Hitachi A/R Specs?

I was wondering if anyone knew the A/R specs (hotside) for the stock hitachi turbo in a TII?
Hitachi HT-18 I believe.






__________________
1990 TII, fresh rebuild
Atkins rebuild kit, RA apex seals
Med. Streetport, TB mod, rebuilt turbo, ported wastegate, GodSpeed FMIC
RacingBeat Turbo-back straight exhaust, Bonez test pipe, emissions/nest removed
hks intake, Walbro, Profec B spec-2
Justen is offline   Reply With Quote
Old 02-20-2010, 08:23 PM   #2
djmtsu
My minds tellin' me no...
 
djmtsu's Avatar
 
Join Date: Feb 2008
Location: Murfreesboro, TN
iTrader: (10)
Posts: 4,043
Rep Power: 21
djmtsu will become famous soon enough
Default

I would ask Brian at BNR. If anyone could tell you detailed specs, its him!!!

I remember reading somewhere about specs of S4 vs S5 as far as A/R and compressor efficiency tables, but I can't find it anymore.
__________________
1976 Mazda Cosmo RX-5
1976 Mazda Cosmo RX-5
2003 Toyota Tundra TRD
2015 Toyota 4Runner SR5
djmtsu is offline   Reply With Quote
Old 02-20-2010, 10:03 PM   #3
need RX7
Clean S4 Nutswinger
 
need RX7's Avatar
 
Join Date: Mar 2008
Location: Sterling Heights, MI
iTrader: (0)
Posts: 485
Rep Power: 17
need RX7 is on a distinguished road
Default

I remember reading it somewhere once. I believe one of them was in the .80 range and the other in the .90 range.

EDIT: this thread says the S4 is a 0.86 a/r and the S5 is 1.00 a/r, not sure how accurate that may be though.
__________________
-Ted
-1986 Mazda RX7 Sport [DD/beater]: engine finally let go at 205k. parts car status.
-1986 Mazda RX7 base [resto-mod project]: S5 n/a swap in progress.


Last edited by need RX7; 02-20-2010 at 10:06 PM..
need RX7 is offline   Reply With Quote
Old 02-20-2010, 10:12 PM   #4
djmtsu
My minds tellin' me no...
 
djmtsu's Avatar
 
Join Date: Feb 2008
Location: Murfreesboro, TN
iTrader: (10)
Posts: 4,043
Rep Power: 21
djmtsu will become famous soon enough
Default

Yeah, that seems a little high.

I thought the S5 was .86ish.

I know by slapping on the T04 back plate, compressor wheel, and compressor housing you basically make a full T04 turbo, albeit with a smaller turbine than what you would normally upgrade to if you did a full T04 turbo kit.
__________________
1976 Mazda Cosmo RX-5
1976 Mazda Cosmo RX-5
2003 Toyota Tundra TRD
2015 Toyota 4Runner SR5
djmtsu is offline   Reply With Quote
Old 02-21-2010, 01:58 AM   #5
Justen
In Too Deep
 
Justen's Avatar
 
Join Date: Jun 2009
Location: Clifton, NJ
iTrader: (3)
Posts: 112
Rep Power: 16
Justen is on a distinguished road
Default

Quote:
Originally Posted by djmtsu View Post
Yeah, that seems a little high.

I thought the S5 was .86ish.

I know by slapping on the T04 back plate, compressor wheel, and compressor housing you basically make a full T04 turbo, albeit with a smaller turbine than what you would normally upgrade to if you did a full T04 turbo kit.
Okay, so its pretty high, around 0.80 to 1.00 a/r
I notice that a lot of the "larger" turbos that people use have a high a/r also (around 0.80 to 1.00)...

Newb question: If I were to step up to a larger turbo for peak/top-end power, I'd just be looking for a similar turbine a/r, and a higher COMPRESSOR TRIM, right?
__________________
1990 TII, fresh rebuild
Atkins rebuild kit, RA apex seals
Med. Streetport, TB mod, rebuilt turbo, ported wastegate, GodSpeed FMIC
RacingBeat Turbo-back straight exhaust, Bonez test pipe, emissions/nest removed
hks intake, Walbro, Profec B spec-2

Last edited by Justen; 02-21-2010 at 02:06 AM..
Justen is offline   Reply With Quote
Old 02-21-2010, 05:31 AM   #6
RETed
RCC Addict
 
Join Date: Mar 2008
Location: Honolulu, Hawaii USA
iTrader: (1)
Posts: 1,813
Rep Power: 18
RETed will become famous soon enough
Default

You cannot be comparing (turbine) A/R's from different family or turbos.

A 1.00 A/R T3 is going to be smaller than a 0.8x A/R T4 (numbers are not necessarily real), even though numerically the T3 is "bigger".

The Hitachi does not directly compare to any of the Garrett family, so you really cannot be comparing them.

Also, the HT-18 2S designed for the FC3S 13BT uses a different type of turbine wheel which will change it's efficiency.
Almost all the other (aftermarket) turbos are designed for piston engines with greater than or equal to at least 4 cylinders of combustion, but the Hitachi turbos are designed for the stronger pulse of a rotary engine.

If you're looking for a starting point for an aftermarket turbo, try around 0.9x for a good overall power band.
Up to 1.00 (or more) for more top end.
Drop to 0.8x for more response on the low end (but sacraficing top end).
Keep in mind that these numbers are strictly for (Garrett) T4 family size of turbos.

As a rule, compressor wheel dictates maximum power potential; turbine (A/R) section dictates whether the power will be low, middle, or high in the RPM band.


-Ted
__________________
reted_2000@yahoo.com
Technical Advisor
FC3S Pro
http://fc3spro.com/



Quote:
Originally Posted by TitaniumTT View Post
because you're only as good as your backup
RETed is offline   Reply With Quote
Old 02-21-2010, 01:24 PM   #7
Justen
In Too Deep
 
Justen's Avatar
 
Join Date: Jun 2009
Location: Clifton, NJ
iTrader: (3)
Posts: 112
Rep Power: 16
Justen is on a distinguished road
Default

I see. I guess it makes sense that the hotside a/r would differ from t3 to t4, since the turbine housings differ in size.
Thanks for info, Ted.

-Justen
__________________
1990 TII, fresh rebuild
Atkins rebuild kit, RA apex seals
Med. Streetport, TB mod, rebuilt turbo, ported wastegate, GodSpeed FMIC
RacingBeat Turbo-back straight exhaust, Bonez test pipe, emissions/nest removed
hks intake, Walbro, Profec B spec-2
Justen is offline   Reply With Quote
Old 04-20-2010, 04:13 PM   #8
sen2two
KTEC
 
sen2two's Avatar
 
Join Date: Jan 2009
iTrader: (2)
Posts: 642
Rep Power: 0
sen2two is on a distinguished road
Default

Whats the exducer and inducer size of the stock turbos (s4 and s5) cold and hot side?

any one know them?
__________________
what I have:
1985 Gs:12a All motor Drag car - 1973 Rx2: Play car
What I had:
93 Touring: TRADED - 91 Coupe: TRADED - 90 GTU: RHD - 88 10AE: SOLD - 87 Base: SOLD - 86 Base: SOLD - 1985 GSLSE - 85 Gsl: SOLD - 80 Gs: TRADED - 1972 Rx2
sen2two is offline   Reply With Quote
Old 04-20-2010, 08:24 PM   #9
sen2two
KTEC
 
sen2two's Avatar
 
Join Date: Jan 2009
iTrader: (2)
Posts: 642
Rep Power: 0
sen2two is on a distinguished road
Default

found them:




Stock TII turbo specs


Turbine major: 2.51" (63.75 mm)
Turbine exducer: 2.15" (54.61 mm)

Compressor inducer: 1.72" (43.68 mm)
Compressor exducer: 2.48" (63 mm) = (48 trim)
__________________
what I have:
1985 Gs:12a All motor Drag car - 1973 Rx2: Play car
What I had:
93 Touring: TRADED - 91 Coupe: TRADED - 90 GTU: RHD - 88 10AE: SOLD - 87 Base: SOLD - 86 Base: SOLD - 1985 GSLSE - 85 Gsl: SOLD - 80 Gs: TRADED - 1972 Rx2
sen2two is offline   Reply With Quote
Old 04-20-2010, 08:26 PM   #10
sen2two
KTEC
 
sen2two's Avatar
 
Join Date: Jan 2009
iTrader: (2)
Posts: 642
Rep Power: 0
sen2two is on a distinguished road
Default

so anyone know the specs of the BNR upgraded compressor blades???
__________________
what I have:
1985 Gs:12a All motor Drag car - 1973 Rx2: Play car
What I had:
93 Touring: TRADED - 91 Coupe: TRADED - 90 GTU: RHD - 88 10AE: SOLD - 87 Base: SOLD - 86 Base: SOLD - 1985 GSLSE - 85 Gsl: SOLD - 80 Gs: TRADED - 1972 Rx2
sen2two is offline   Reply With Quote
Old 04-21-2010, 08:27 PM   #11
88turboii
destroy, rebuild, repeat
 
88turboii's Avatar
 
Join Date: Feb 2008
Location: Charleston, SC
iTrader: (0)
Posts: 395
Rep Power: 17
88turboii is on a distinguished road
Default

i know a BNR stage 3 uses a 60-1 hifi wheel which is 59/76mm (2.3/3"), with .60 A/R cover

the stage 4 is basically the same except the turbine is modified for a P-trim turbine wheel, which is clipped to prevent boost creep i believe. the p-trim is 2.544/2.922"


not sure about stages 1,2
88turboii is offline   Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -5. The time now is 01:03 AM.


Powered by vBulletin® Version 3.8.4
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Hosted by www.GotPlacement.com
Ad Management by RedTyger