Advantages on supra turbo ct26 over alltrac ct26?

Q&A regarding engines, turbos, and intercoolers and power upgrades

Postby tw2 » Sat Nov 04, 2006 7:47 am

alltrac7 wrote::shrug:

Sorry I do not know how much you know but...... if you are thinking of getting a bigger turbo since you need one anyway you should probably do a bit of research. You should definitely learn to read a compressor map so you can understand how a given turbo will respond and how all the trade off's work. This is a start http://www.gnttype.org/techarea/turbo/turboflow.html also http://www.stealth316.com/2-3s-compflowmaps.htm Obviously it is based around the mitsubishi gto but the principals are the same. The stock ct26 is round about a T3 40 to 44 trim i think i read somewhere just for comparison. If you pm me I can also send you a basic excel spreadsheet which will allow you to calculate all the values needed to use a given compressor map. There are also turbine maps which are very important but these are almost completely unavailable or do not exist. Garrett have some grude ones for their turbos but they are incomplete and not very useful.
Image The ct26 is slightly "bigger" than this map
Members don't see the above ad. Register now - it's free!
Thomas, JDM 90 185, 06 350z
User avatar
tw2
Established Member
 
Posts: 2909
Joined: Sun Dec 11, 2005 3:01 am
Location: Hamilton, New Zealand

Postby toayoztan » Sat Nov 04, 2006 7:53 am

For information on turbo and compressor maps, you can also read up on here:
http://www.turbobygarrett.com/turbobyga ... ch103.html

A little involed though. You can also go here:

http://enginelogics.com/cmaps.html

Bryan
2017 Pilot Elite
2014 Juke NISMO RS
1994 Supra TT 6spd
1993 Alltrac - http://www.alltrac.net/phpBB2/viewtopic.php?f=44&t=37466
1977 Celica GT Liftback
2015 Grom
1977 GL1000
User avatar
toayoztan
GTFour God
 
Posts: 6734
Images: 1
Joined: Wed Aug 11, 2004 5:51 am
Location: Oklahoma

1993 Toyota Celica

Postby tw2 » Sat Nov 04, 2006 8:02 am

My approach to choosing a turbo is

1) decide what is important; ie fast spool, high top end, mid range torque etc
2) guestimate a possible turbo and find its compressor map or similar
3) see if it will fit your needs on paper, look at different trims as well
4) no doubt you will not find a turbine map; otherwise helpful in selecting an appropriate hot side A/R which will affect spool quite a lot
5) there is lots of info on mr2oc on how various turbo's perform for people- read up, boost threshold (rpm when starts to make positive pressure) is quite useful
6) also finding dyno plots of the turbo on various cars- obviously important to look at what other mods they have done especially volumetric efficiency improving mods. ie t3/t4 57 trim requires improved VE (cams etc) to sit properly in its efficiency range (in this case not surge around 18psi i think it was reported) whereas the 46 and 50 trims are fine.
7) then you should have a pretty good idea how a turbo will work out for you.
Thomas, JDM 90 185, 06 350z
User avatar
tw2
Established Member
 
Posts: 2909
Joined: Sun Dec 11, 2005 3:01 am
Location: Hamilton, New Zealand

Postby maxaud » Sat Nov 04, 2006 6:08 pm

also, if looking for a CT20b, don't accidentally purchase a regular ct20 because it's a good deal, The older Toyota Trucks used ct20's and they are quite a bit smaller. They were used on the 22re making it a 22rte, also heard of a 22rtec and 22ret, though some may just be the same engine call'd different things.

I had one for my Toyota Truck, but I sold the set-up to a guy that was building a mini-truck.
-Dustin
Image
User avatar
maxaud
GTFour God
 
Posts: 3306
Joined: Sun Jul 10, 2005 4:33 pm
Location: Sandpoint, Idaho, USA

1992 Toyota Celica

Postby smog7 » Sat Nov 04, 2006 6:28 pm

how do you tell the difference then?
-omar
my car doesn't leak oil, it just marks its territory
rally tarmac 1990 st185
User avatar
smog7
GTFour God
 
Posts: 3025
Joined: Wed Sep 27, 2006 8:34 pm
Location: central coast, ca

Postby Gary » Sat Nov 04, 2006 7:54 pm

This has been discussed several times.
Do a search on "CT20B"
93 ST185
Image
Gary
GTFour God
 
Posts: 6430
Joined: Sun Aug 08, 2004 1:03 pm
Location: Carolina

Postby smog7 » Sat Nov 04, 2006 8:18 pm

what type of turbo do most of you people use then?? do most of you still have the stock ct26? how many have rebuilt ct26's?
-omar
my car doesn't leak oil, it just marks its territory
rally tarmac 1990 st185
User avatar
smog7
GTFour God
 
Posts: 3025
Joined: Wed Sep 27, 2006 8:34 pm
Location: central coast, ca

Postby tw2 » Sat Nov 04, 2006 8:24 pm

I get the impression that most people on the forum still have the stock ct26. A few have the ct27 and the ct20b. It is quite a lot of work to custom fit the turbo of your choice. The bolt on kits from KO, ATS etc are good value for money but none the less are very expensive for most people. I personally still have my stock ct26 (I have done custom turbo upgrades on other cars). I personally will use a t3/t4 50 or 57 trim (with cams) when I am no longer reliant on my car as my sole means of transport (im at uni).
Thomas, JDM 90 185, 06 350z
User avatar
tw2
Established Member
 
Posts: 2909
Joined: Sun Dec 11, 2005 3:01 am
Location: Hamilton, New Zealand

Postby smog7 » Sat Nov 04, 2006 8:29 pm

im leaning more towards just rebuilding my ct26....i still dont have to worry about for a while though....
-omar
my car doesn't leak oil, it just marks its territory
rally tarmac 1990 st185
User avatar
smog7
GTFour God
 
Posts: 3025
Joined: Wed Sep 27, 2006 8:34 pm
Location: central coast, ca

Postby tw2 » Sat Nov 04, 2006 8:36 pm

It is probably the safest, most reliable option. You can always upgrade later in the future, a rebuilt ct26 will still be worth something. If you get a 46 trim wheel or something put in it you might get another 10hp or somethng anyway.
Thomas, JDM 90 185, 06 350z
User avatar
tw2
Established Member
 
Posts: 2909
Joined: Sun Dec 11, 2005 3:01 am
Location: Hamilton, New Zealand

Postby smog7 » Sat Nov 04, 2006 8:37 pm

im not looking for incredible horsepower i just something with a little more power... so yeah im going to rebuild.....
-omar
my car doesn't leak oil, it just marks its territory
rally tarmac 1990 st185
User avatar
smog7
GTFour God
 
Posts: 3025
Joined: Wed Sep 27, 2006 8:34 pm
Location: central coast, ca

Postby alltracman78 » Sat Nov 04, 2006 11:36 pm

Man, 3 pages of almost nothing on the CT26.....

allblackalltrac wrote:But enough about those turbo's this thread is about CT26's
CT26A from the 7MGTE motor found in the Supra MA70.
The "A" denotes the CT26 from the Supra, its cast directly into the turbine housing.
It is a single entry turbo and capable of 300hp and unlike the ct26 found on the MR2 and AllTrac, boost will not start to fall off at high RPMs and is capable of producing more efficent boost beyond 16psi.
It is also a direct bolt on for the 1G3SGTE, with only the need the clock the center cartrige and impeller housing - the exducer housing bolts to the single entry manifold and turbo elbow of the 1G3SGTE.
Low milage CT26A can be purchased for as little as $100 and rebuilds for $400.
Several turbo rebuilders also offer upgrades of the CT26A the most notiable upgrade being the T4 60-1 capable of 500+hp
This upgrade actually replaces the center cartrige with a Garret unit and if you are resourceful enough can find one for as little as $700 all the while retaining that "factory" appearance.


This is the most accurate, though it's not 100% correct.

I'm going to ignore the ST165 and it's CT26.

IMO, the CT20b is WAY overpriced.
I wouldn't pay $500 for it.
Probably not even $400.
But whatever.

The 2 inaccuracies above are
1-You clock JUST the compressor housing, NOT the CHRA [Center Housing Rotational Assembly] when you install on a 3SGTE.
It happens to be a bit easier than clocking the CHRA.

2-Those 500hp "upgrades" are bullshit.
Even on a 7MGTE you will not hit 500 hp with one, never mind on a 3SGTE. Not even close. Don't bother with ANY of the Supra CT26 "upgrades".

Here are the facts. I have torn apart a CT26 or 10, so this is from personal, hands on experience. I currently am running a Supra CT26 on my 92.
Personally, I am happier with the Supra one than a 50T I had a while back. It is a DEFINITE improvement at higher boost over the 3SGTE CT26. However, I also have a remapped ECU that can take advantage of the higher boost. And a better IC. I'm running 16 PSI at the moment.

The CHRA from either CT26 is identical. Except for the compressor wheel.

The Supra compressor wheel is VERY close to the 46T upgrade found on the CT27 and upgraded CT26s. It is SMALLER than a 50T wheel on a 3SGTE CT26.

All that is needed to bolt a Supra CT26 to a 3SGTE is to swap the exhaust housings. You unbolt the clamp in the center of the turbo, and knock off the exhaust housing. It will NOT want to come off most likely.
Use a block of wood, a vice, and a large hammer for persuasion.
And alot of PB Blaster.
Install your 3SGTE exhaust housing, then clock the compressor housing to fit.
You will have to slightly bend the wg actuator rod to make it work on the clocked housing.

OR, you can get a Supra compressor housing and wheel and mount them on your 3SGTE CT26. You will still have to clock the compressor housing and bend the rod.

I happen to have a Supra compressor housing for sale at the moment. [I did NOT answer this just to try to sell you this. However, since the opportunity is here, I'm going to put it out there. :)]
It is in the FS section.
If you are interested, you can buy it and source a Supra compressor wheel. Normally they are pretty easy to find on ebay for ~ $25. However, I just did a quick search for you, and I didn't see any. :shrug:

Regardless, good luck with what you do use, and I hope this taught you something.
Image
User avatar
alltracman78
GTFour God
 
Posts: 4675
Joined: Mon Aug 09, 2004 9:04 am
Location: Ma

Postby alltracman78 » Sat Nov 04, 2006 11:39 pm

Oh, and as far as a rebuild, I have had several done.
From MY experience [not necessarily the full story]
Stay away from Performance Techniques in CA.

My best quality rebuild came from ATS racing.
However, they did leave me waiting for 2 friggin months, and I had a HELL of a time getting ahold of anyone and resolving it. And, FYI, they don't do the rebuilds in house, they are sent out. I don't know to where.
But, in the end I did receive a turbo with ZERO shaft play that I was happy with until my damn clutch went. :lol:
Image
User avatar
alltracman78
GTFour God
 
Posts: 4675
Joined: Mon Aug 09, 2004 9:04 am
Location: Ma

Postby allblackalltrac » Sun Nov 05, 2006 3:44 am

Thanks for some clarification, I myself was wondering if those "upgrades" actually produce what they say they can as I never had any experience with one. However it begs the question as to how TTE has managed to break the fabled HP output of a CT26.

My CT26A is a complete turbo - exhaust housing included, from the Supra. I have a 1G3SGTE so no need to swap housings. I had it rebuild to "0" stage by Majestic Turbo in Texas. When installing it to the car I clocked the CHRA 1-2 degrees cause the oil feed/return line flange did not mate up 100% flush, so instead of bending the lines I clocked the CHRA. The impeller housing obviously had to be clocked and I did have to modify the wastegate bracket.

I as well have noticed this turbo to perform alot better than my old twin entry CT26 w/ 46 trim T04E wheel and 10* clip on the exhaust side. I did not get an oportunity to compair the exhaust housing between the two but the compairison between the Alltrac single entry and Supra single entry CT26 was significant - the Supra CT26A exhaust housing is larger than the Alltrac CT26 exducer housing.

A quick search on ebay revealed these impeller wheels:
LINK 1
LINK 2

I'll plug the fact that I as well have two CT26 impeller housings but they are from the Alltrac CT and they are not advertised as being for sale, however anything is for sale given the right offer is made :wink:
SupraCelifragilisticexpialidocious
super- "above," cali- "beauty," fragilistic- "delicate," expiali- "to atone," and docious- "educable," the sum meaning roughly "Atoning for extreme and delicate beauty while still being highly educable."
allblackalltrac
Gold Member
 
Posts: 914
Joined: Sun Aug 08, 2004 3:14 pm
Location: Toronto, ON

Postby alltracman78 » Sun Nov 05, 2006 5:08 am

allblackalltrac wrote:THowever it begs the question as to how TTE has managed to break the fabled HP output of a CT26.


WTA IC and tuning.
And some other stuff.

Remember, they had [almost] unlimited funds, and the knowledge of the folks that actually designed these turbos.

And a restrictor.

If I remember correctly [I'm a bit timposy], they were running roughly 300 hp and 6oo ft/lbs torque......
Image
User avatar
alltracman78
GTFour God
 
Posts: 4675
Joined: Mon Aug 09, 2004 9:04 am
Location: Ma

PreviousNext

Return to Performance and Power

Who is online

Users browsing this forum: No registered users and 1 guest