Why run twins when the new singles are so good?

[Clmsnow]

Trying to figure out if I am better off running twins or just a good single(like a SPS62) for a truck I am about to build. I keep hearing mixed stories and don't want to regret anything. Looking to use a Smarty, pressure box and maybe injectors to be in the 550-600hp range. Obviously all the transmission and fuel mods will be done, but I can't get a straight answer on the turbo(s). The truck will be used as a daily driver and I will tow on the weekends at elevation(5000-7000ft) during the winter, but only like 2000lbs. If money was not an option, what are the pros/cons of each? Thanks.

 

[Forrest Nearing]

you may like a small set of twins at that altitude, my problem is they spool up too slow

 

[driverno8]

I had a 62 single on my truck for a year or so. Did great. But went to twins and would never go back to a single. But with a Smarty, pressure and injectors you're going to get warm. With a single you'll get hot, espcially towing unless you keep your rpms up. Go with twins and be done with it. . 02¢

 

[TCluff]

Trying to figure out if I am better off running twins or just a good single(like a SPS62) for a truck I am about to build. I keep hearing mixed stories and don't want to regret anything. Looking to use a Smarty, pressure box and maybe injectors to be in the 550-600hp range. Obviously all the transmission and fuel mods will be done, but I can't get a straight answer on the turbo(s). The truck will be used as a daily driver and I will tow on the weekends at elevation(5000-7000ft) during the winter, but only like 2000lbs. If money was not an option, what are the pros/cons of each? Thanks.

I HAVE FRIENDS THAT RUN LARGE SINGLES, I RUN TWINS AND STAY COOLER WITH THE SAME SETUP..... MY TWINS LIGHT AT 15-1600 RPM AND GO FROM 20-70PSI REAL QUICK , TOW AWESOME, DAILY DRIVE GREAT, I WONT GO BACK UNLESS ITS NOT ON A DAILY DRIVER... 19 MPG HWY WITH 37INCH 10 PLY MUD TIRES, AS LONG AS I STAY UNDER 80MPH...

 

[mattymac]

Go with twins. In the hills a good single that will tow (64 or smaller) will not cool 5-600 HP (trust me) If I were you I would look into the BD twins, fast spool, good cooling, clean, proven, and I know to many people that run 12 second 1320's with em.



BTW who did your 1140? Ive never heard of a 1200 cc twin making over about 220 on full kill!

 

[d90boy]

If you're only towing 2000 lbs I don't think it's going to matter what route you go, you shouldn't have EGT issues. If money is no object why not go for twins though.

 

[Gary - K7GLD]

It possibly isn't a simple issue of single/twins - but also the necessary associated engine work that's required to accommodate higher boost PSI - and the expense of studs/O-rings, etc. , need to be figured into the cost total.



Dunno what the actual PSI threshold difference is between a hot single and twins as far as required head work is concerned, but sorta suspect the cost of associated and needed engine mods get heavier faster with the twins...

 

[TCluff]

I Have Been Running 75 Psi With Only Studs And The Gasket Showed No Signs Of Leakage In 6000 Miles Of Abuse, Arp 12mm Torqued At 132 Ftlbs With Arp Moly Lube... .

 

[bmoeller]

With your hp goal and the elevation, I think twins will be the way to go. A 62, and maybe even the 64, will be to small. The 64 may be too laggy at altitude.

When I still had the PDR 40 and 370s, I couldn't keep the EGTs in check, other than with my right foot. Was only pulling a small 3-4k# (loaded) enclosed trailer, and couldn't go over 55 or 60mph til the ambient temp went down to 40, and the wind calmed down. Anything higer than that, the EGTs would hit 1300* pretty quick.

Was pulling about 12-15k# yesterday. Was under 40mph for most of it, due to the crappy rural roads we have here (oiled gravel). As long as the T/C would unlock going up hill and not lugging the engine, I could keep the EGTs in check. Still curious what the EGTs will do on the big road with a heavy trailer.

I can hit 1450-1500* @ WOT on the flat, empty, with my current setup. Will adjust the wastegates for higher boost. Opens @ 38# right now. Will aim for 42#, and see how it does.

NO headwork to date. Original h/g as of yet. No studs.

 

[Gary - K7GLD]

I can hit 1450-1500* @ WOT on the flat, empty, with my current setup. Will adjust the wastegates for higher boost. Opens @ 38# right now. Will aim for 42#, and see how it does.



NO headwork to date. Original h/g as of yet. No studs.

You're not running all that more boost PSI with your setup than I am with my OEM HX-32 - so I can see why you haven't run into headwork yet...



It's my understanding that as boost closes in on 40 PSI, things start failing with stock heads and gaskets, especially in towing situations where LONG distances up steep grades at max boost are in use. Not quite the same as a stoplite-to-stoplite bash as some city street warriors are involved in.



And if most serious RVers are like me, the LAST thing I want in a towing situation, is to be busted down 1000 miles from home in Podunk Hollow, and depending on a greasy and pimply-faced kid to get me back on the road. So GAMBLING on adding substantial boost to a purely STOCK engine just isn't in my deck of cards!



If it isn't as dead-on reliable as an anvil as I can make it, it ain't leaving my yard! :-laf

 

[bmoeller]

You're not running all that more boost PSI with your setup than I am with my OEM HX-32 - so I can see why you haven't run into headwork yet...

Before bumping my timing, I was making 45# with the PDR40 and 370s. After bumping it, the boost came down to 38#.

After using hair spray, I haven't blown off an intercooler boot since. :-laf

The 64 clears up the smoke a LOT better than the 40 did.

I have heard of guys using a small set of twins, and setting the 'gates to peak out @ 40#.

 

[Morse]

I've run the same combination on an 05 crew cab dually (8,040 pound race weight), and an 06 2500 (6350 raceweight). The dually is used to carry equipment and the play trucks (12-18,000 pound trailer weight). It pulled great and ran 13. 0's in the quarter. My 06 2500 is doing low 12's at 111 mph in the quarter with EGT's leveling off around 1450. All I run is a PS62-14, 90hp DDP injectors, and now a beta Smarty on the 06. I ran a Scary Larry on the dually. Well, and also transmission mods. Some parts just work very well together without going to a huge expense. . As far as elevation, I have no experience with it.

 

[Clmsnow]

Think I'll do the twins in that case. Thanks for all the help guys. When I do the project later this year I'll report back.



mattymac. PM'd you about the sled. Actaully hit 232hp on the dyno, 240 was a little exagerating on my part Custom built by Struthers. 1 of 5 built.