Engine/Transmission (1998.5 - 2002) Twin Turbos, Pros & Cons

[Cliffman]

As most of you know I toasted my engine pulling a 6% grade with my 15K 5er in tow. See post https://www.turbodieselregister.com/forums/showthread.php?threadid=93389&goto=newpost.



I thinking of installing the PDR twin turbo's to help with extended high EGT's when pulling long grades. What are the pros and cons of twin turbo's when pulling long grades? I'm also looking for dependability.



Pros:

1) Cooler EGT's

2) 2 turbo’s work less then 1 turbo

3) More horse power





Cons:

1) Cost

2) Higher cylinder pressure. This one I'm worried about.

 

[willyslover]

twins will help for sure as EGT's will start the water temps to raise fast .



IMHO. . the whole issue is the water temps anyway... we need to go to a larger radiator also... can't wait til you or Blair gets the twins installed to see the effects of the EGT reduction on the water temps issue v/s a big hill like Hwy 58 or 152 [but 152 is to short a pull to test real well even though it got you LOL ]

 

[Snow man]

Cliffman, in hot weather the coolant temps will soar you'll have to back out of it anyway. In colder weather you'll be able to stay in it longer. You being concerned about higher cyl pressures is smart. IMO there are no guarrantees that the head gasket it going to hold up at the boost levels we see with twins. I would consider 0 ringing and studds as the minimum you'll need,and dont expect it to last forever.

 

[Cliffman]

A bigger/better flowing radiator sounds like a good idea. What are my radiator options men?

 

[BPINE]

What's up with Evil Auto's radiator upgrade, do you know Gary?

 

[csevers]

More "cons"

More wieght at least 75lbs. . Turbo 60lbs + piping

Less room under hood

Take's more fueling to spool them

Cost



Just some things I was thinking of

Craig

 

[Cliffman]

The turbo wieghs 60 lbs:--) That's one heavy turbo. Guess we'll use the engine puller to install it.

 

[DRAG DIESEL]

Horsepower = Heat.



You can do all you want to make the EGTs cool, but the fact still stands to make hp it takes heat.



I towed massive loads all last summer and the best cooling results I had on the stock radiator was with straight water and "water wetter" additive. I could run at 1250* at 90+ degrees amibent, all day. When it would break 100* going up tword Mt. Lassen up that slow windy road where you can barley keep 35mph... . it would overheat at 800*.



The ulitimate would be a 6 or 8 row aluminum radiator that bolts up to the stock location... . I have a friend that owns a rad manufaturing co here in Sac... I could give him the dimentions and see what would fit... . it am positve the stock unit could be improved upon... everones bound to buy a new rad sometime anyhow, right?



... . ever thought about spraying a fine mist of water over your rad when your pulling a hill? I have seen old motorhomes that have this, you know the old dodge motorhomes with the camed-up 440's in them.



Just a few quick thought.



Have a great day guys!

~Jake (DD)

 

[BPINE]

Hey Jake doesn't copper work better in radiators, I'm pretty sure. The reasons race cars and newer auto's use aluminum is for weight and cost. I do agree though that HP is heat and there is no way around that.

We also have to remember we are in some situations over fueling our trucks so more air will help that.

 

[Joseph Donnelly]

By the time the ambient air goes through a couple radiator cores, it is too hot to do much cooling on further rows. That is why you don't see 4 core radiators often, with 3 core being about the max. You should see a gain in cooling going to the 12 valve copper core radiator as copper transfers heat about twice as well as aluminum.

 

[ThrottleJockey]

Ciffman.



THAT is the MAIN reason for lowering your CR! Then you can increase your manifold pressure up to the point where the extra boost is beneficial and backpressure is greatly decreased!



Low compression

Retarded timing

Increased manifold pressure



and... . the best part,



more fuel!



Brian

 

[ThrottleJockey]

Youv'e already got Electronic Variable Timing, take advantage of it. And if you set it up this way, it won't hammer at the rods, mains and crank. It'll last a lot longer.



Brian

 

[KLockliear]

My feeling is that under 550hp, twins add another level of commitment. We have had good success with properly sized singles at various HP levels up to and including 800hp. Obviously for towing, you will likely be dealing with 450hp or less.



A good single and a cam will be cheaper and gain you more IMO.



Twin Pros: EGT control at higher boost levels above those with a single, marginal to good gains in power when levels exceed 550hp.



Twin Cons: Cost - not only of the two turbos and piping, but also for o-ringing the block to use that extra PSI, Complexity - more piping and more things to go wrong.



YMMV

 

[BPINE]

Originally posted by KLockliear

My feeling is that under 550hp, twins add another level of commitment. We have had good success with properly sized singles at various HP levels up to and including 800hp. Obviously for towing, you will likely be dealing with 450hp or less.



A good single and a cam will be cheaper and gain you more IMO.



Twin Pros: EGT control at higher boost levels above those with a single, marginal to good gains in power when levels exceed 550hp.



Twin Cons: Cost - not only of the two turbos and piping, but also for o-ringing the block to use that extra PSI, Complexity - more piping and more things to go wrong.



YMMV

Hey Kieth I am still waiting for a ride in your 03 pulling my 14k 5er up that grade to Purump at 70+ miles an hour at 1200 degrees. When I see that I will be a believer but until then I still have some doubt.

 

[BPINE]

Originally posted by Joseph Donnelly

By the time the ambient air goes through a couple radiator cores, it is too hot to do much cooling on further rows. That is why you don't see 4 core radiators often, with 3 core being about the max. You should see a gain in cooling going to the 12 valve copper core radiator as copper transfers heat about twice as well as aluminum.

Hey didn't I just say that ?



Hey Joe I have a question for you, over time does the piston material change and allow it just to melt down one day even though you have run it at 1300 + degrees many times. I'm not sure I worded that correctly but sure would like to talk about it.

 

[OPoole]

would a bigger innercooler help in this situation,sense it is in front of the rad. ? i have heard of the term. . heat soaked innercooler ??

 

[BillGotthelf]

Lets see adding 60 more pounds to a truck that ways over 7000lbs... Hmmmmm... gotta buy bigger tires I guess. I have not seen the coolant temp increase yet. I do see lower egt's over my old PDRHX40. Yup you sure do gotta do a lot more to the motor to support the twins but you gotta love the ZOOM ZOOM.

 

[Vaughn MacKenzie]

Blowby effects?

High Cylinder Pressures. . . I always hear everyone concerned about the head gasket, but don't forget about the effects of increased blowby on cylinders, pistons, and rings. I don't know what the long-term implications are but certainly high pressures and resulting increased blowby will accelerate ring wear. Well likely it will wear out faster due to high HP, and it's a tradeoff like everything else in life. When you take your engine this far how important to you is it that i lasts another 100-200K miles? Maybe the high pressures blow oil out from around the rings and make them more starved for lubrication? Just thinking out loud. . .



Vaughn

 

[SRadke]

Good point Vaughn. I had a thought though. If you lower your compression ratio to in turn drop your cylinder pressures would you not be making it easier on the parts that you mention when not operating at insane hp levels? In my mind it would even extend the life of pistons and rings under normal driving conditions. Of course that is in my mind.



-Scott

 

[KLockliear]

Originally posted by BPINE

Hey Kieth I am still waiting for a ride in your 03 pulling my 14k 5er up that grade to Purump at 70+ miles an hour at 1200 degrees. When I see that I will be a believer but until then I still have some doubt.

Bring your wallet and I'll make the time for Lawrence. Seriously, I don't think we have to go do that to prove it, but if you're gonna step up and buy some product when we do, I'm sure I can make time.