I fit is a single turbo it is probably a CT26 off of a 7MGTE Supra
This may be a little off centre for you guys, I'm currently looking to replace the turbo on my Toyota 2.4 turbo diesel. After doing several mods to improve the engines breathing I upped the boost from the standard 8 pounds to 13 pounds, now I have bad compressor surge over 3200 revs, in fact the boost drops back down to 5 p.s.i. when the dreaded surge hits. Cutting slots in the compressors intake hasn't improved things, (this is a C.T. 20 turbo, designed in 1985 for sloooow diesels) Rather than muck around with the standard dinosaur, I decided to find a turbo off a similar sized toyota petrol engine. A friend has a turbo off a Supra, but he couldn't remember which year or motor, so until I get my grubby diesel blackened hands on it I can only ask you guys just how many different turbo's came off the Supra model. Being relatively new to turbo's, I'm still trying to get my head around compressor maps, so that I will have some idea of how this supra (or other) turbo will go on a diesel engine. I know that the exhaust gas temps of a diesel are much lower than a petrol engined car, but don't know how this will affect spool up time. I can't find a map for the C.T. 20 turbo, so will have to go on calculated airflow basis. The engine is a 2.4 litre diesel with 2 valves per cylinder, and has a very low valve overlap camshaft, with a redline at 4000 revs. I have improved the breathing of the intake/head/exhaust as much as I can without reducing reliability, so would "estimate" a volumetric efficency percentage as around 75 % to 80 % if that helps. In standard trim the engine puts out about (don't laugh now) 60 to 70 horses........so you can see why I'm looking for more neddies, it just ain't enough!!!. I have driven a later model (early 90s) mazda turbo diesel that went like a petrol engine of the same size, with the turbo kicking in at 1500 revs and tailing off at around 4000 revs, this is what I would like to achieve in my patheticly slow oil burner. Any comments or help in calculating turbo characteristics would be greatly appreciated. Remember that a diesel can't ping like a petrol engine, so 14 pounds of boost without intercooling or similar mods is quite do-able. Thanks for any input, road4runner.
I fit is a single turbo it is probably a CT26 off of a 7MGTE Supra
|| 91 MX83 Cressida Grande 1JZGTE - Daily || 84 MA61 Supra 2JZGE - Track ||
if its a 2l-t(e) and its over boosting (the red led on the tacho) then your wastegate is fubar. replace this and then your over boost problem will be solved.
RA23 - Twincharged
JZZ20 - Daily
Thanks for the feedback, I will do a search on the c.t.26 and see if I can find a map to ponder over. The engine is a 2l.t., not the 2l.t.e., the difference is that the "E" stands for electronically controlled injection pump, so mine has the mechanical pump, I upped the boost on purpose by putting washers between the wastegate controller bracket and the mount (compressor housing) , this is what gave me the 13 pounds that I wanted. After calculating the airflow required at redline (4000 revs) (around 248 c/f/m or 17.3 pounds) and also at half redline (124 c/f/m or 8.6 pounds) I can now make sense of compressor maps in order to see if I'm going to have an efficient turbo or another "surger", Thanks for the info Road4runner.
The CT26 makes a fair bit more air than that. The 1HDTE (4.2L landcruiser diesel) uses a version of the CT26, although I'm sure there would be a difference in the wheel trim / design than the petrol version.
Suggest try looking for a turbo off something like the 1KZTE (early 3Litre hilux), or the 2.8L isuzu out of an older rodeo etc. These would more than likely be closer to what you want.
Also, try looking around at diesel turbo kit suppliers such as denco, ray hall, AJS etc, and seeing if they mention turbo sizings for their kits.
Hope that helps.
Lee.
Thanks for the info fella's , I still havn't got my hands on the c.t.26 turbo or a compressor map, when the xmas rush is over and things get back to normal I might actually get something done!!
I used to own a 7MGTE Supra with a CT26 turbo and its wrong for your application. For starters the supra had a redline of 6250rpm and the turbo didn't show usable boost to 2500rpm and made power all the way to redline. The motor was 24 valves and had 3 litres to have off boost torque. You need to hunt down a turbo off the later three litre hilux motor will be ideal for your application and flow more air at increased boost.
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