12H-T performance Build (1 Viewer)

[gbentink]

QUOTE:
VTCruiser, I'd expect an engine with higher compression to have a lower exhaust gas temp for the same fuel loading. In addition the IDI head loses more gas temperature to the coolant.
Maybe they just liked the engine to rev more with the bigger housing?[/QUOTE]

The VE tends to be better because the intake ports are not swirl type. I have looked at both, no comparison by the looks of it, but no measurements on a bench to back up. Granted that the head absorbs more heat too... however in view of our previous discussion on AR of exhaust, the improved VE would aincrease mass flow, wheras the temps will not....

Sound reasonable??

 

[gbentink]

Actually beyond the CT26 quality and capabilites ... I'm much more concern about the 12H-T or 1HD-T block and head resistance to up boost levels like 18 PSI plus PSI :.

Rods, pistons, studs, head etc ..

Hi Tapage: The 1HDT is DESIGNED for 30psi continuously, also up to 315HP!. As for the 12HT, it is a engine that looks strongly built and has more metal between the cylinders and water jacket than the 1HDT by a fair margin (16mm vs 11mm!) and uses a nice 6 bolt setup (very low head torque though I thought - 85ftlbs). I have no idea on what is truly safe on the 12HT. At a guess I would say less than the 1HD family though for rods, but better as far as head gasket. Can't have everything I guess. I am tossing up using after market conrods in the stroker build but I am trying to minimise costs where possible and I have nio idea about what they can handle.

Anyone out there know of a 160mm long conrod that is from a turbo diesel?? Close enough would be OK to consider! Maybe from a Isuzu 3.9 (Hey Dougal)??

 

[Dougal]

Anyone out there know of a 160mm long conrod that is from a turbo diesel?? Close enough would be OK to consider! Maybe from a Isuzu 3.9 (Hey Dougal)??

Those are some pretty short con-rods. Mine are 199mm centre to centre.
I still think it's a stretch comparing a marinised version to an automotive engine.

 

[gbentink]

Quote: I still think it's a stretch comparing a marinised version to an automotive engine.

Fair comment, though the block, head, crank and rods are the same. You would need to look at alot of cooling changes and a more efficient turbo setup to get the power long term. Even the 315HP is actually a short term rating in Marinised form, long term I think was ~ 270HP Mark. Point is that that is probably a thermal limitation and I was really only considering the inherent strength.

Re: Conrod length. Thanks for checking. 199mm, that is a bit dissapointing for me (huge).... You want short? Try around 130mm for the 1H"x" series, thats short! Considering the stroke is 100mm, it is impressively short and makes for a "compact" inline 6cyl for its capacity. As for piston to wall loading....has to be high. Nissan TD42 is 157mm and I did consider the Nissan rod and it is still a worthwhile option for a stock piston 12HT. But since I am using pistons of a different compression height, is not an option for me.

 

[gbentink]

Here is Maarten's Response:

Thanks for checking on that, I figured larger, so there you go. I think the reasons mentioned though are not entirely accurate; as Dougal mentioned.

 

[Tapage]

Hi Tapage: The 1HDT is DESIGNED for 30psi continuously, also up to 315HP!.

sure .. where do you get this info .. ?

if they are designed that high why they come factory with only 168 HP . ? and 9 PSI of boost .?

 

[gbentink]

Hi Tapage: Check out the Yanmar and Yamaha marinised version of the engines (T/FT). They both run about 1.9-2.1 Bar. Turbo is entirely different and I think the Yamaha has bronze inserts in the pistons. My point though was inherent strength of block, rods, pistons, head, crank. Would take more than 30psi to get that power out of an auto engine though, and more efficient turbos etc.

 

[gbentink]

Dougal: I have noticed that as compressor trim increases, so does the overall efficiency, at the expense of a poorer surge line. Very intersting, and makes sense too when you think about it.

So, the "Big" turbo in a twin setup should have a very large trim, I am guessing also on the exhaust side

 

[gbentink]

Also Dougal, Mazda had the "Pressure Wave Supercharger" which while an exhaust resonance type, is nonetheless a 2.0L 4 cycle factory supercharged diesel used in the Capella circa 1988-1991 therabouts

 

[Dougal]

Also Dougal, Mazda had the "pressure Wave Supercharger" which while an exhaust resonance type, is nonetheless a 4 cycle factory supercharged diesel

Yes they did, almost 20 years ago and they haven't been back since. It delivered a monstrous 88hp which is pretty embarassing for a boosted 2 litre diesel.
Mazda Capella Wagon 1995, SV Grade - specs and pics at AMAYAMA.COM

Technically isn't a comprex an exhaust driven supercharger (aka turbo with a different mechanism)?

 

[Dougal]

Dougal: I have noticed that as compressor trim increases, so does the overall efficiency, at the expense of a poorer surge line. Very intersting, and makes sense too when you think about it.

So, the "Big" turbo in a twin setup should have a very large trim, I am guessing also on the exhaust side

I think axial compressors are more efficient and as you get to 100% trim it's getting closer to an axial. Technically mixed flow rather than radial.

But axial compressors don't compress as well. Depends how much boost you need really. As pressure ratios rise, compressor trim has to fall.

 

[gbentink]

My VNT actuator arrived. Has same bush size as the turbo, so thats good. Now for a basic bracket....

For now I am struggling with Exhaust mass flow restrictions, I am sure there is more too it than saying lb's/min. There must be assumptions in there. I also dont think compressibility is a problem or non ideal gas behavious, I think it is their assumptions. Now, need to know what they are.

I will be modding a CT26 for the benefit hopefully of others. That will be fitted first, tested probably not intercooled.

 

[Dougal]

For now I am struggling with Exhaust mass flow restrictions, I am sure there is more too it than saying lb's/min. There must be assumptions in there. I also dont think compressibility is a problem or non ideal gas behavious, I think it is their assumptions. Now, need to know what they are.

The bottom line is, you can only get soo much air through a certain sized hole. Increase the temp and the sonic velocity increases so you can get a little more. But higher temp is bigger volume which will counter the sonic velocity increase.
Each way I cut this problem, I keep coming back to a similar mass flow rate.

Increasing the pressure on the exhaust side to keep the outlet density higher works, but doing that stops your turbo from working (unless it's a compound setup). So yeah, keep coming back to fixed flow for a single setup.

I still plan to try the GT37 like I suggested. Here is a copy of a dyno (@ wheels as I understand) from a 300E Merc 3 litre 12 valve 6cyl IDI with ~ 44psi boost from exactly my turbo. No smoke either BTW and they improved the low end response to do 14psi @ 2000rpm a little while later. No cam mods or porting etc. Modded injector pump though. I have had this dyno for ages. This engine was torque limited to save known gearbox issues above 600nm. I think it is very impressive.

Peak torque at 3800rpm. Guess that's also peak boost.
I make the AF ratio 17:1 at that point, with some assumptions of course. So it will have some smoke. 36.4 lb/min.
To get a better AF ratio, it'd need a BSFC better than 240 g/kwh, which may be possible, but unlikely in an IDI diesel.

Which car is that? There are videos around of most of the 300d's tweaked that high, virtually all of them pump black smoke until on boost. That graph shows it getting no boost until 2800rpm, the torque delivered there is comparable to an overfueled NA motor.

 

[gbentink]

I edited the last post because I will back it up with data after I do it, I am a bit tired of the twoing and froing on what it does or doesnt or can or cant do.

I understand where you are coming from, dont get me wrong, it is fun and educational discussion, but I am more intersted now though in backing up my guffaw with some real data, otherwise it mkaes for pointless discussion.

As for the twin turbo, a large housing TD06 with the 55mm exducer would do what I am looking for, just need to find one. It should be cheaper than a Garrett alternative. TC06 might work with upgraded compressor to 20G.

As a result, I have decided that I will post again when I have some measured data.

I will post results on

- CT26 with the upgraded compressor, no IC

- Any results from the IC

- Any results from other turbo mods whether they be a big single/twin or the like.

See you soon with some results!

 

[gbentink]

Took vehicle over a weighbridge yesterday, 2420kg with me in it, to be sure on weight.

Used the G-tech to measure based on that weight and taking off in second gear (auto). No TC lockup. 133hp @ wheels ~3500rpm. Feels like it too - accelerates like a typical big family sedan and does it with no fuss. Some smoke, but not objectional.

 

[gbentink]

Should have engine built in 2 weeks, running CT26, high flowed (by me) and 20psi boost. A friend now owns the engine and wants to go conservative.

 

[Hulsty]

Any info on what you have done with the turbo?

I'm looking for some info to improve the CT26 on my 13BT in the future, some of what you have done should apply even though the mass flow rates would be different. I would love the turbo to be able to reliably and efficiently run past 15psi boost.

 

[Adam B]

Glad to see this thread is still alive.

I've been at 16psi for a couple of months now and am very happy. It's interesting to learn just how over-fuelled I was at 13psi. Knocked 200F off the EGTs at high altitude with the extra boost.

I'd love to be able to run my CT26 at 20psi with complete confidence. Long term.

 

[gbentink]

For manual box 18psi (and in auto up to 25psi), I reccomend 16G large comp wheel. For > boost I recomend 20G comp wheel and 360 thrust bearing.

13BT is a fairly small capacity for a CT26. The CT26 is basically a GT30 size turbine. On 13BT I would probably buy a 100 series turbo and use that as it is. 17% smaller turbine than CT26 and 46mm inducer. Can mod with 360 deg thrust bearing to run high boost.

PM me for a price. I am happy to do it - you post me your turbo, I post it back. 2-3 week turn around if I dont have comp wheel in stock

 

[Dougal]

For manual box 18psi (and in auto up to 25psi), I reccomend 16G large comp wheel. For > boost I recomend 20G comp wheel and 360 thrust bearing.

13BT is a fairly small capacity for a CT26. The CT26 is basically a GT30 size turbine. On 13BT I would probably buy a 100 series turbo and use that as it is. 17% smaller turbine than CT26 and 46mm inducer. Can mod with 360 deg thrust bearing to run high boost.

PM me for a price. I am happy to do it - you post me your turbo, I post it back. 2-3 week turn around if I dont have comp wheel in stock

The 100 series turbo is also a CT26. They are buried under heat-shields but I might be able to get some identifying numbers if you tell me where to look.

While the turbine wheel maybe physically GT30 diameter, diameter is not a reliable indicator of flow capacity. l can show you some holsets which are bigger but have simliar airflow to a T2.