Primary turbo options?

[RonA]

With all the new singles coming out monthly, is there anything new for the bottom? Are any shops playing with Ball Bearing turbos. New top is being ported and would like to try something other than the usual 3B, B2 stuff. Anyone try a GT 4202R or Turbonetics. I imagine it is all secret like always, but it never hurts to ask.

 

[Cooker]

It would be nice to hear what some guys are running as primaries besides 3b's and B2's

 

[Diesel Freak]

You would need a wastgate on the GT42R. I will prolly use that turbo or something slightly smaller in the future.



While still on the drawing board, a GT37/GT42R (with the 102mm exducer and 53 trim comp wheel) combo should be able to support 600 HP very easily.



Then there is my personal choice for a 650 HP combo of a Q trim t66 with a (censored trim) t88.



For all around "truck" use, I really want to try a HX40/16 with a S trim T76 for up to 550 HP. Another nice setup for a truck that gets used as a truck would be a wastgated Q trim T58, and a S trim T76



All these combo's require wastgates on BOTH turbos to keep boost at sane, and "usefull" levels.



Pop off valves on the intake piping are CRAP for boost controll!!!!

 

[RonA]

DF.

Do you know of anyone who is using any of these turbos? The whole ball bearing thing looks good on paper and on a web site, but when you talk to the engineers at some of these places and mention Diesel. You can almost hear the blank expression their faces. I wonder if the Ford guys would have any info on BB turbos. They tend to use larger singles and I have heard that they use BB turbos to make them more driveable.

Ron

 

[Diesel Freak]

main reason you dont see these turbos is cost.



HX35s, HX40s, and HT3B are cheap. The turbine staging between even the HX40 and the HT3B is terrible. The HT3B turbine is just too big. I know people have "made" it work, but it can be done better.



I have read about one truck using a T70/T91 combo!!!

 

[Diesel Freak]

Keep this in mind when searching for a turbo. In the gasser world, the HP rating is usually with a 12:1 to 13:1 air fuel ratio. In the Diesel World, useable power starts at an air fuel ratio of greater than 18:1.



With this in mind, a P trim T66 that is rated at 700 HP on a gasser is only good for basicly 466 HP on a diesel.

 

[paulb]

A/F is not the issue. The issue would be how much air is required to make 700HP in a diesel, compaired to how much for gasoline. A/F is based on weight of both fuel and air, and the weight of gasoline is different per gallon, then diesel, so compairing A/F ratios for the amount of air required to produce 700hp is invalid. Finding the BSFC for an engine running diesel, and one on gas, and then using the A/F ratio applied to the pounds of fuel you would probably come up closer to the air requirements.

 

[Diesel Freak]

Paul, thanks for adding to the thread.



I realize I over generalized here, and I know I ommited the BSFC for the engines... I did this for keeping it simple. But you have to admit, once BOMBed, the factory BSFC curve for an engine has been changed radicly. I doubt that the BSCF curve for my truck is the same for another 475-500 HP truck. But I bet it is close.



At stoic, gasoline and diesel run basicly the same A/F ratio, 14. 6, and 14. 5 respectively. Yes it is possible to run both engines close to these conditions, but neither will like it, and I have yet to see a material that can withstand the heat. Not saying that it does not exist, but that it currently is not available for use nor is it in the price range of the average Joe.



Without BSFC curves, all we have to go on is the bulk fuel and air consumed... . the BIG assumption (which you pointed out) is that the engines have the same thermal efficiency. But you have to admit... . they are somewhere between 18-30%



My guess is that a BOMBed engine is closer to 18% than 30%.



The Smoke Point for diesel starts at basicly 18:1... and gets worse as you get richer. Combustion temps start to climb, NOx goes up from the heat, and the power the engine generates is no longer useable for anything but a cool looking show in a Dyno, or a run down the track.



I look at power a little differently than everyone else here (save a select few). I want useable continuous smoke free power. This can not be achieved at an A/F ratio of 14. 5:1 in a diesel engine. IMO the only way to really use all the fuel is to keep the A/F ratio greater than 18:1. That way all the ECO Freaks are happy (except for the rise in NOx from the high boost pressures... . hmm I should address this next... . how about Cooled EGR!!! ) and we all have the ability to run a "cool" 550-600 HP.



From what I could dig up, gasoline and light diesel have heating values (LHV) of 18341 BTU/LBM, and 18574 BTU/LBM respectively.



If you have other data, please post it. I had to do some digging to find these. Most of the data I found was in BTU/gall

 

[Diesel Freak]

RonA what are the specs on your top turbo?

 

[RonA]

Bell WSB. No info available, not even a housing size. But i compared wheels and housings to a turbo that JR Adkins made for me that i know would work well. Almost identical. It is larger on the exhaust side than my current turbo, and smaller on the compressor side. I have heard they spool very fast also. Basicly a pig in a sack. Just like most turbos. But I know it is a well built pig in a sack.

 

[Diesel Freak]

This should muddy the waters some!!!



http://www.turbobygarrett.com/turbobygarrett/products/catalog.html

 

[RonA]

Muddy water is usually better for fishing. I talked to a couple of people this week that had failures with Ball Bearing turbos. It sounds like it is pretty common. I think this new top turbo and external wastegate are going to drop my drive pressure down 15lbs at full boost. That will probabaly do me alot more good than a new bottom turbo.