Towability with a twin over the 68Stg2R?

C

calereeves

Displaced Texan
Jul 13, 2011
135
1
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I just picked up a shiny new 68 Stg2R to cap off my new build. Haven't even ordered the Fingers pistons yet (waiting to find out what the block cleans at) and I'm already considering going twins. Looks like Mark recommends the S480 or S483 over the 68, but I'm curious what that'd tow like.

My truck is a DD, intended to be a fun toy for 99% of the time. But there's that once every 1-3 years when Uncle Same sends me off to my new home, and the truck, above all else, HAS to be capable of towing my 52' enclosed trailer, potentially across country (last move was Alaska to NJ!) loaded up to ~24k. If the truck can't tow the trailer the few times that it has to, then the truck is worthless to me.

Obviously the tune would be the key, but I'm curious if the hardware would support that kind of sustained load if I put a billet S480(+) over the top.


Thanks!
Cale
 
DaJokr

DaJokr

Slum Lord Extraordinaire
Mar 7, 2013
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Prince George, BC, Canada
I would think either would work well. My understanding is twins are great for towing. I was personally planning on the 68 with the 480 over it, but I have heard the 483 is a better match. Hope someone can chime in with more detail. Maybe call and ask Mark himself.
 
Chevy1925

Chevy1925

don't know sh!t about IFS
Staff member
Oct 21, 2009
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your issue will be temps. if you run any tune over 500rwhp, oil temps, fuel temps and coolant temps will be a fight the whole way if outside temps are 90* or more. Your EGTs will stay nice and cool though on a good tune.

i am generally 22-23k gross with my fifth wheel and truck. i run a modded stock IHI with an s483 under it. Soon to have a 68 stage2r in the IHIs place. i tow on a real world 600rwhp tune, i also DD on it and travel long distance on it (its my smallest tune). to tow that much weight at that much hp, i had to add a giant oil cooler up front, a muuuuch better fuel cooler, an intercooler that doesnt leak, thoroughly clean my radiator and keep it clean, make sure the fan clutch is 100% working, and keep an eye on all gauges. i still have to be careful pulling long grades in the middle of summer but summer here is 115* outside temp.

so that said, there is ALOT more to add to the truck to keep things cool and in check if you want to use the HP this setup can make. Verlon and Howard6.6 tow on even more HP than i do but they have bigger coolers than i do. My stock radiator is taxed at this point.

if your injectors arent an ungodly size, a good small tune will keep things in check and you pulling that trailer along happily. The turbos wont be an issue, the tune and other parts you have on the truck or dont have will be. make sure you have an oil temp gauge in that bad boy, twins like to heat it up fast
 
Chevy1925

Chevy1925

don't know sh!t about IFS
Staff member
Oct 21, 2009
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as for 480 or 483. buy the 483. there is hardly any noticable difference in the big turbo lag from an s475 to s480 to s483. ive had all 3 :D. and the 483 pulls like an SOB up top! mine has a race cover and TCT wheel in it though.
 
Chevy1925

Chevy1925

don't know sh!t about IFS
Staff member
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you start pushing over 260 on reg dino oil, you need to back out of it. you start running a sustained 260 or above it, the oil starts breaking down. Synthetic will take up to 300*. If your oil temp is at or over 260*, its a good bet coolant temp is at 230-240+ so you will be backing out of it anyhow. i always run syn oil in the summer for the protection and change it every 5k. at that power and heat, its cheap insurance. so far so good with 41k on the build.
 
V

Verlon at ATP

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Mar 19, 2015
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As stated above, with twins it is not the egt's that are the concern. I towed all day long at 650hp at 20-21k combined. I could set the cruise at 80 and go. That much horsepower builds heat even if your egt's are being kept in check. The stg2r 68 with the 483 is a super combo. Spools easily and drives great.

If you plan to tow at any hp above 500, plan on adding all of the coolers listed in the above post. Oil is my main concern. With the expensive cooler I bought from killer bee, I saw a 30 degrees reduction in oil temps and haven't seen above 245 while towing with a 700hp tune on my LBZ.

On my LLY with a 420hp tune, twins and no cooler, I have seen 265 on the oil temps. I have recently added a cooler made by a customer of ours that looks like it will do an excellent job keeping temps down. I will be putting it to the test as a built motor is going back into the lly and I will be towing on the 650 tune again.

I have coolers on my return and fuel feed and have never noticed any great reduction on the fuel temps. I also run an upgraded tranny cooler up front and an additional one at the rear with a fan. That helps a lot.

Bottom line. If you plan to tow much weight with more than 500hp, do everything you can to keep all of your temps down. Bigger radiator and intercooler will help to.
 
Awenta

Awenta

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Sep 28, 2014
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There's a plug on the filter housing

Sent from my SM-N910V using Tapatalk
 
C

calereeves

Displaced Texan
Jul 13, 2011
135
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Thanks for the info, Gents! I'll be doing some serious tow-related upgrades before the next trip. Right now focus is getting the motor built. I've got a little while before the next one, but this last one, coming through Alaska and the Canadian Rockies with stock brakes and stock exhaust brake got....dicey.....a few times. And the factory cooling was bullshit. I'm going with a PacBrake, and some sort of additional engine coolant cooling, though I'm not sure what yet. And perhaps most importantly, I've decided to upgrade the brakes, most likely to the SSBCs or depending on how long it is until I get my next set of orders, hopefully the big 16-inchers I've seen, inside some 20" wheels. We'll see. Lets get through this $15k+ engine build first!


For auxiliary trans and oil cooling, are there any of the aftermarket coolers to stay away from, or are they all fairly equal? What about radiator options?
 
Chevy1925

Chevy1925

don't know sh!t about IFS
Staff member
Oct 21, 2009
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CentolaCCSB said:
Aaaaaand whats the best place to monitor that temp from? Oil filter?
Click to expand...


I don't wanna sound like a dick so don't take it that way but there is a ton of info on that subject if you do a quick search. Should answer all the questions your after
 
henery97

henery97

Member
Apr 4, 2011
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Oil temps can be managed if you are really careful but it is still far from ideal. I towed 23-25k combined with my lbz on a 500-525rwhp tune and my oil temps were at 240-260 the entire time. If I got brave and tried to get after it they rose quickly. I had no problems with coolant temp, most I saw was 220 but it hung out around 205-210. Trans temp was also managable at 195-205. This is with all stock coolers, electric fans, and 100-110 degree outside air. Like I said it's far from ideal but for once every 3 years it's doable.
 
DaJokr

DaJokr

Slum Lord Extraordinaire
Mar 7, 2013
450
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Prince George, BC, Canada
Mishimoto has some solid cooling options for radiator and intercooler IMO. If I every need to replace the factory stuff, I'll be installing mishimoto to replace it.
 
C

calereeves

Displaced Texan
Jul 13, 2011
135
1
18
Wow... this is a whole 'nother can of worms that I'll be looking into when I move again. This last trip, and the blown motor during it, really opened my eyes to the need for a better "whole package" towing rig. Looks like I've got some great toilet reading for the rest of the week :)
 
clrussell

clrussell

pro-procrastinator
Sep 23, 2013
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Fyi save money on the pac brake and don't install it..

Use tuning in your favor for turbo brake, it works just as well and is free with tuning
 
N

N2BRK

Well-known member
Dec 31, 2009
1,898
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Why can't you just use dsp5 to select a tune in the 400hp range to tow heavy? I'm confused as to why it sounds like you have to tow with so much power? I've never had twins, so excuse me if I'm ignorant of the twin-towing facts :), but I recall people towing more weight with less power.
 
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