Turbo Theory-Small Compounds

[Andyba20]

It seems like everybody thumbs their noses at small compounds these days, but everyone I’ve ever talked to that has had them loved them. I’m specifically referring to stock/s300 type setups, I’m pretty sure the old BD kits used an S300 as the primary. Any idea why we don’t see that setup offered much anymore? Is it just due to a shrinking market and the S400 working better for the 5.9/6.7 crowd as a whole? I’d think someone valuing quick spool and low egt’s more than big power would enjoy the smaller setup…any theories? I’m sure I’m oversimplifying  it or missing something. Maybe they really are good set ups, there’s just not a big enough market for vendors to sell them. 

[AH64ID]

Probably because the people that are common on the internet with the older trucks aren’t the type that tows heavy. It’s just been too long since these older trucks were king. 
 

No matter the mods a stock 4.5 Gen will out tow/handle a 2nd Gen.  So mods don’t focus on towing, they focus on fun.  

[Andyba20]

That makes sense. So for a sub 450hp rig is there still an advantage to a small set of compounds, or could the same performance be met with modern tuning and the right single? To be specific, at 1800 rpm in 4th gear (OD) could a well tuned single match the boost of a small set of compounds. Towing 5K on 4% grade for 1/2 mile in this example. 

[Tractorman]

1 hour ago, Andyba20 said:

To be specific, at 1800 rpm in 4th gear (OD) could a well tuned single match the boost of a small set of compounds. Towing 5K on 4% grade for 1/2 mile in this example. 

 

I think so.  I already do that with the original OEM turbo (HX35), RV275 hp injectors, and mild tune with a Smarty S03.  My travel trailer is light - a little over 5,000 lbs (GCW is 12,500 lbs) and I pull 6% grades for 5 or 6 miles in 6th gear 60-65 mph (1,800 - 1,900 rpm) with egt's staying right around 1,150°.  Kind of similar to what you are asking.  I can easily attain 30 psi boost above 1,700 rpm, but a 6% grade will call for about 25-27 psi boost.

 

- John

[AH64ID]

5K and and 4% grade isn’t much, so tuning and a single for that is easy. 
 

I had my 05 able to pull at 6% grade in 6th at 70 up thru 7K feet on a 75° day and not break 1250° at GCW’s above 18K. That was as hard as I could push it at those rpms. 2200+ rpms and I could pull any grade at any weight and elevation.  
 

It was tuned to the point where a pyro wasn’t needed,  but I was the tuner and spent a lot of time on it. It was 415/850 to the ground so around 480/1000 at the crank. 
 

My stock 18 (385/930) would put pull the 05 below 2000 rpms. They were the same 2000-2400 and the 05 won above 2400. The 22 out pulls the 05 below 2800, hands down. No real need for those kind of rpms on a 6.7 thou. 
 

I did want small towing twins on the 05, but I could never justify the cost. 

Edited December 17, 2022 by AH64ID

[Andyba20]

Good info, thanks. Where I live nothing is flat, everything is a gently rolling hill. I lock out OD when I tow heavy, but it gets annoying if I’m towing light on the interstate and have to drop to 3rd to maintain speed juuust as I’m nearing the top of a hill (over and over and over for miles). With my 3.55 and 32.7” tires I’m at 1750-1800 at 70mph. I don’t tow my horses any faster than 65, so 3rd gear is fine, but anything not alive I’ll tow 70-75 on the interstate. I’ve had the 62sxe and infinite perf 7x.010’s sitting in the garage for a few months and I need to get things going, but I just don’t think the 62 is right for me. I think it would be awesome to tow with in 3rd when I’m at 2000-2500rpm, but it seems like it would be pretty much worthless to me in 4th. I think I’d love the he351cw, but then I thought well if I’m gonna go through the effort of plumbing and clocking that turbo maybe I should go a little further and do some small compounds. The reviews seems mixed from guys who tow with the 62,  most seem to really like the 351cw, and I really don’t think I’ve heard one bad thing about small compounds. 

Edited December 17, 2022 by Andyba20

[Tractorman]

45 minutes ago, AH64ID said:

I did want small towing twins on the 05, but I could never justify the cost. 

 

Same here for my '02.  Plus I would have to relocate the exhaust brake - didn't want to do that.

 

- John

[Hutch24v]

Some food for thought here on a single towing turbo setup over compounds. I’ve put a couple thousand miles now on a ATS 3000 (58/72/12) and it spools quick with enough top end. I’m happy with the performance towing my TC and boat behind it through the WA state mountains passes. I’d say this is a close performing turbo to the 57/65 GX-E turb which a lot of people seem to like. With the right tune and maybe a slightly smaller tire you might be just as happy with a single rig. 
 

Mark 

[Silverwolf2691]

@Andyba20, what are the rest of the specs on the turbo? My brothers second gen had a 62/65/12 and was spooled relatively quick (15-1700 rpm-ish).. My 62/68/14 wont spool until after 2k rpm. (Waiting till after the holidays to find a 12 cm housing..)

 

[Andyba20]

7 hours ago, Hutch24v said:

Some food for thought here on a single towing turbo setup over compounds. I’ve put a couple thousand miles now on a ATS 3000 (58/72/12) and it spools quick with enough top end. I’m happy with the performance towing my TC and boat behind it through the WA state mountains passes. I’d say this is a close performing turbo to the 57/65 GX-E turb which a lot of people seem to like. With the right tune and maybe a slightly smaller tire you might be just as happy with a single rig. 
 

Mark 

Thanks for the tip, Hutch. I’ll definitely check that one out a little closer. I was going to move to the 57GXE but even that one I was told won’t spool like stock. That’s when I started looking at the he351cw, the compounds, and I’ve talked to Bradley at Savage Fabrication who is a really good dude. Even his Super 9 won’t spool as low as stock. I could go down 1 size to stock tires, but these are brand new. If tuning and the 7x.010’s can get me around my 1750 boost issue then maybe I’m good. Main reason I started this thread was because of all the different options I listed, it seems that the compounds were the clear winner in satisfied users. But I appreciate getting everyone’s input and opinions. Btw @AH64ID was it you that an he351 with a modified turbine wheel at one time? Where would that unit fall into the conversation? 

 

6 hours ago, Silverwolf2691 said:

@Andyba20, what are the rest of the specs on the turbo? My brothers second gen had a 62/65/12 and was spooled relatively quick (15-1700 rpm-ish).. My 62/68/14 wont spool until after 2k rpm. (Waiting till after the holidays to find a 12 cm housing..)

 

It’s a 62/68/12. I’ve brought this up a few times this year, actually kinda being a pu***% about it and need to just make a decision and get to work. My concern with the 62 is from talking with so many that didn’t love it to tow with. I’m trying to stay under 450hp, I have a well built trans with all new good stuff,  but it does have a super single billet converter so I’m really 

trying to keep the power mildish and reliable. The place I’m needing the most help is in OD at 1750rpm. I’m at about 70mph at 1750 and if I could get a turbo setup to spool a litter earlier that would be helpful at maintaining slight grades when towing light. DAP told me the

62 would shine towing between 2100-2600 rpm…I just won’t be at that range often. 

 

Edited December 18, 2022 by Andyba20

[AH64ID]

We put a modified HE351CW into dad's 06 with a G56. It did everything better than the stock turbo, spooled sooner, pushed harder thru redline, ran cooler, and probably increased airflow and NOx (only reason I can think they went smaller). All it had was the larger turbine wheel off of a HE351VE put into it. 

 

Not sure how it would react in an automatic VP truck, but I can't see how it could be bad. 

 

For heavy and higher altitude towing I figure its about a 375-400 rwhp turbo, but we kept Dad's around 350-375 rwhp. 

Edited December 19, 2022 by AH64ID

[jlwelding]

Im new to the turbo talk, when I bought mine I went to DAP and  explained what I do with the truck and they suggested the 57 65 12 borgwarner  all I can say is I'm thrilled how it performs. Its good up to 400hp and when im on flat ground it has no boost and the slightest hill it responds without accelerating. Perfect for hauling, it cools down a lot faster than my stock turbo. As soon as I back out of it temps drop real nice and when loaded I pull off and its cooled down to 275 in no time. When down shifting it will come down to 200- 225.
Im running stock except for 50hp injectors and getting 18 mpg with loaded out tool boxes. If I had to guess the weight Id say 9k lbs.

[Silverwolf2691]

Probably the only turbo that would give stock like spool with more flow on both sides would be the he351cw. Otherwise every size larger of any aspect of a turbo will slow spool.

 

Next closest would be k27, gxe, or the small hx super 9. He351ve is in there too but has much more needed to get it installed. Then 62/65/12 sxe or the larger hx super 9...

 

For the rpm range you want, smaller wheels would be better, especially since the sxe line doesnt have a 9 cm housing. 

[Mopar1973Man]

I've been back on my stock turbo HX35W (54/60/12). Still doing good with my +150HP injectors. I see zero need for even a bigger turbo or twins any time soon. Heck with my current setup and tune I see maybe 0 to 1 PSI of boost at 55 MPH and at 65 MPH maybe 2 to 3 PSI of boost. WOT I'm set up for 35 PSI and very very difficult to even reach the 1,200*F EGT's. I will say the biggest thing to make it spool fast and stay cooler EGT's is attempt to get the final ratio close to 3.73 to the ground. 

 

Just a sample...

 

[Silverwolf2691]

Mike, what does your fuel curve look like?

 

I had a thought rereading this.. If I had to guess the small compound thing was based around the 12v crowd and early 24v tuners. A way to have bigger injectors while keeping things cool and relatively smoke free when going bigger on injectors. Especially due to the lack of on the fly timing and fueling in a 12v. 

 

The control that we have now over fuel and timing allow us to utilize a larger group of smaller single turbos and still keep things cool and smoke free. 

 

Just my thoughts^

 

I hate doing the whole turbo talk thing.. it's very subjective.. the only hard data we have is wheel and housing sizes and turbo efficiency maps (and the general person is gonna go crosseyed trying to interpret those at first glance). 

 

Spool up times are generally very setup dependent and are a subjective number. Then add in multiple turbos or turbos off other engines (big rigs and tractors) and all bets are off. Then add in the "one persons lag is another person's fast spool" aspect and things get muddy fast.

 

Im gonna stop there otherwise im gonna need a new thread.. 

[Mopar1973Man]

6 hours ago, Silverwolf2691 said:

Mike, what does your fuel curve look like?

Well... I'm starting as low as 60% on Zero boost and ramping to 100% by 5 PSI remain 100% till 15 PSI and ramp up to 150% at 30+ psi. Way better cold engine protection with it locked low like that EGTs max out at the most of 800*F with heavy throttle. Allows for a slow warm up while driving highway speeds. Basically the low end is about perfect stock fuel levels (235 HP at the flywheel). Not even a puff of smoke now it totally clean from launch to WOT. Runs right at 2-3 PSI boost at 65 MPH. Then at 82 MPH I'm barely 650-700*F but twisting 2,450 RPM and still barely 5 to 6 PSI. 

 

On snow and ice the performance is much better way less tire spin on the slick roads and builds power slow enough that even more enjoyable to drive. Yeah my trip to Everett WA I was using this new fuel table and highly impressed with the EGT's and driving performance. Pulling a U-haul trailer just about half filled, bucking a head wind, drove through drifting snow, and even managed driving on ice covered roads. Very stable and you don't have to be precise with the throttle with the deep cut at the bottom that you can let your foot twitch and it isn't going to spin the tires out from under you. 

Edited December 29, 2022 by Mopar1973Man

[Sycostang67]

I swapped from the stock HY35 last year to the 57GXE and 100hp injectors.  It did seem to spool a little slower than stock.  This last summer though I did the crazy carls 2/3 compound kit and put a S400 75mm turbo on top and the whole setup seems to spool much quicker now.  It's building boost around 13-1500rpm.  I haven't had the chance to tow with it yet, really looking forward to it this spring though.  The truck is a lot more fun to drive and it sounds like a jet engine now.