Finally set up and towing a trailer, sort of...now what do I do?

[Pre-StrokerC150]

After spending a bunch of money setting up my '99 K2500 OBS for towing (hitch, brake controller, weight distribition, special drop shank, and wiring) I finally bought my travel trailer this weekend. I picked it up on Saturday ready to try out all my new stuff with my new 26', 5700lb trailer. The truck is lifted 9" with 35's, 4.56 gears and a supercharged 350 engine.

Up until Saturday, I had never towed anything, ever, so I didn't know what to expect. The "trainer" at the trailer place showed me how to hook everything up and before I knew it the truck and trailer were one. The rear end squats very little and it sits perfectly level within a half inch. The first thing I notice towing is that this sumbitch is heavy. However, once I got it on the freeway it towed nice and straight and hardly felt like anything was behind me. And then...a hill.

You know those people that you pass and flip off because they aren't going the speed limit on the freeway, that was me. The truck tows great with the suspension setup I have but it just doesn't have enough balls. When I push my foot down further and get into some boost, she pings really bad, even with the 160-degree thermostat and Shell premium gasoline, plus I literally just did a Seafoam treatment so there's no carbon buildups in the combustion chamber. At this point I'm not sure what to do. I wish the truck had a 454 but that's not going to happen. I really like the truck but I live in Washington State and we have lots of hills around here. It would really suck if I was going camping and melted all 8 pistons down because of this.

What should be next for me? Our first trip is planned for Labor day so I'll be able to try out shifting down to second and I planned on running some octane booster in preparation for the bigger hills. Would a cam swap yield enough of an increase in torque to help me? Should I cut my losses and find another truck with a bigger engine (454, an LS or even diesel)?

[throttleking]

I would try to work with what you have. Maybe a different tune for towing is what you need.

[jimmyfloyd]

Yeah, seems like a different tune might help. My father towed an 18' open deck car trailer, with my 1970 3/4 4x4 GMC Suburban on it with his 99 OBS Suburban k1500, all stock with 350 and 3:42's in the rear, and it didn't have any issues with it, even over dome decent hills. Granted, I am guessing they aren't as steep as yours. I know he drops it down into 3rd on hills so it isn't trying to switch into OD and back.

[Quyonmob]

Sounds like you aren't tuned/built for towing, as a blown vortec 350 should yank 5700lbs around like a chihuahua on a chain.

Pinging just shouldn't be happening, get that tuned.

Step down to 33's, let those gears do work. (255/85/16 would be my suggestion).

You aren't going to like an LS 5.3 or stock 6.0 if a blown vortec doesn't have the mustard for you.

[Pre-StrokerC150]

Ok, I'll contact Wester's and see what he can do for me. The computer is tuned for the supercharger, but not for towing. Of course these trucks don't have a distributor you can retard the timing with without getting a check engine light.

The supercharger makes the truck go pretty good but the truck itself is 6500lbs. I'm sure it would tow better without the lift and big tires. I just bought these tires about 8 months ago, so I'm not changing them yet.

[ToyHauler]

what gears do you have? if they are the stock, ones they will likely need to be changed i would go pretty aggressive with the change you need to account for the increased wheel diameter and the fact that you have alot of hills

[Pre-StrokerC150]

The gears are not stock. They are 4.56's.

[Badass69]

Ok, I'll contact Wester's and see what he can do for me. The computer is tuned for the supercharger, but not for towing. Of course these trucks don't have a distributor you can retard the timing with without getting a check engine light.

.

There is your problem, Westers. Get a real tuner to tune the truck and it will probably pull just fine. 5700 lbs behind any of my stock 6 liters could still maintain the speed limit even on a grade. A supercharged 350 vortec should not struggle with that kind of weight.

[Pre-StrokerC150]

I went with Wester's because that's what everyone said to go with. Since it doesn't knock without the trailer, and knocks with the trailer, I wouldn't think that the timing was too far away from perfect. It could be going lean, but it's a MAF system, so the computer should be in control of that. I don't want to spend $500+ dollars on another tune only to find out I still don't have enough engine.

[Badass69]

I went with Wester's because that's what everyone said to go with. Since it doesn't knock without the trailer, and knocks with the trailer, I wouldn't think that the timing was too far away from perfect. It could be going lean, but it's a MAF system, so the computer should be in control of that. I don't want to spend $500+ dollars on another tune only to find out I still don't have enough engine.

You have ignition timing or fueling issues. Just because the ping isn't audible without the trailer doesn't mean your knock sensor isn't going crazy pulling a ton of ignition timing.

You aren't pulling anything particularily heavy and your truck is no heavier than any of the 2500 HD's I run, or even my 1500 HD for that matter. Sure the lift and 35's aren't helping but the 4.56 gears you installed do help offset that.

Your truck won't be a rocket sled if that is what you are hoping but if a bone stock LQ4 powered 2500 HD can maintain highway speed with a trailer of that weight or more you have something seriously wrong with yours. Even my 05 1500 HD D.D. would probably wiegh the same as your truck, and it has no trouble tugging 6000 lbs even on some fairly serious grades.

Westers..... I too ignored the internet and all the negative stuff I read thinking, "Hey he is local to me even". That and negative news goes further than positive so I gave him a shot. And what I got was a tune that was for all intents and purposes my stock tune. Once I went elsewhere and had my car retuned by someone else ( PCMforless in this instance) it was night and day. Not to mention PCMforless was half the price......

[mlslocks]

what camper did you get?

[Pre-StrokerC150]

Well damn, maybe I will have it tuned then. Each time I've changed the plugs they look good, so I don't think I have any detonation issues. I know the injector assembly is supposed to be an issue, so maybe it is not getting enough fuel. I changed the poppet assembly for the injector assembly soon after I bought it, but I don't think they are much better a far as delivering fuel under boost.

The trailer is an R-Vision Silver Creek 26'BHS.

[Badass69]

Of course rule out other mechanical issues like fuel pressure, compression/ leakdown test and so on. Even an exhaust issue. If that all checks out and it's still a dog, get it retuned.

[Pre-StrokerC150]

I put a new pump in about a year ago and ended up with 60psi, but I could probably check it again just to be sure. It doesn't burn any oil and the plugs all look good, so I don't think there is any compression problems. Exhaust is new.

[speedracer326]

Are you using the Whippletronics? Do you have a wideband? If not, I'd run out and get one now. With a blower on there, you NEED to know what's going on. You could be lean empty too, but it won't knock audibly until the trailer is hooked up. I question if the stock pump is adequate for a blower.

[Pre-StrokerC150]

The tune got rid of the Whipple ECM, so I don't use it. The Whipple instructions say that there needs to be at least 56psi from the fuel pump and there is 60 the last time I checked. I don't have a wideband anymore. I bought an Innovate stand alone unit a few years ago and that thing was a major pile, so I sent it back. I never got another one.

[speedracer326]

I cannot begin to express how vital the wideband is, especially when someone else is tuning your truck! I don't trust ANYBODY. An internet tune for a blower?! I'm sorry dude, that was a total waste of money. You absolutely cannot guesstimate that. I don't care how good you are, it can't just be shot from the hip like that. Your poppets might not flow enough either, that's right on the edge of what they can take which is why you NEED a wideband to tell you how lean you are. If you're running 15:1 WOT up high, that'll do it. You might shjt bricks when you see your AFR's, I know I did when I first hooked the blower up on my car with a standalone whose maps in boost weren't yet written. I mean they were guesstimated, but they were lean. So I changed it till they were what I wanted. You're still at step one. A Marine intake manifold would be a great option if your injectors are in fact maxxed as that will take a standard injector.

[Pre-StrokerC150]

I talked to a shop that specializes in turbos about dyno tuning what I have. I talked with him for probably 10 minutes and his thoughts are I'm screwed with what I have. The Whipple doesn't have any way of intercooling it so it keeps pumping in hot air and will always detonate as the Whipple is not designed for towing heavy loads. I can counteract this with a meth injection kit, but he said I would need a really large tank that would have to be installed in the bed.

Another thing he said is I am most likely out of injector with the system GM installed in these trucks. The fuel pressure is not adjustable and the injectors were never meant for boost applications so they won't keep up with demands.

His recommendation is to either lay down some serious coin or buy something that will tow better.

He said I could stop by and he can install a wideband and dyno it, but it really needs a marine intake with standard injectors and a supercharger or turbo that can be plumbed for an intercooler.

[boogie_4wheel]

Can you install a different size pulley(s) to slow down the supercharger slightly? Help lower cylinder pressure to help with the detonation. I have a 5600lb toyhauler (empty weight) that is borderline overloading my '97 half-ton. Has the power to pull it but the 60E is my weak link; damn TC keeps unlocking under anything over ~1/2 throttle and generates a ton of heat. If I had the 5spd I would keep the truck! Ended up buying Cummins powered Ram.

Anyway, the N/A 350 is enough motor for your trailer, the tire size is hurting you. You are gonna be in 3rd on flat ground and 2nd on the hills (I am) I just watch my trans temps closely. My opinion is if your charged 350 isn't enough motor then either something is wrong with the motor or your trying to go too damn fast. If your trying to maintain 60+ up decent grade hills you've got the wrong truck.

[speedracer326]

I talked to a shop that specializes in turbos about dyno tuning what I have. I talked with him for probably 10 minutes and his thoughts are I'm screwed with what I have. The Whipple doesn't have any way of intercooling it so it keeps pumping in hot air and will always detonate as the Whipple is not designed for towing heavy loads. I can counteract this with a meth injection kit, but he said I would need a really large tank that would have to be installed in the bed.

Another thing he said is I am most likely out of injector with the system GM installed in these trucks. The fuel pressure is not adjustable and the injectors were never meant for boost applications so they won't keep up with demands.

His recommendation is to either lay down some serious coin or buy something that will tow better.

He said I could stop by and he can install a wideband and dyno it, but it really needs a marine intake with standard injectors and a supercharger or turbo that can be plumbed for an intercooler.

That's exactly what's been said in this thread, now do you believe us? The Whipple can in fact be plumbed for an intercooler, but it's not cheap. boogie beat me to the pulley suggestion as that's what I'm going to do with my blower to avoid the very issues you're having. Have you considered an FMU? I don't know how the poppets would handle an FMU, but it's a thought. Other than that, if you just did the Marine intake with some bigger injectors and a dyno tune, it'd be way cheaper than a new truck and you'd be set. Intercooled would be better, but if you pull enough timing and don't over heat the cylinders (EGT) you can get away without it. Since the MM intake takes time, if I were in your shoes I'd just slow the blower down and get a good dyno tune AND wideband. With a good tune, that motor should make more juice on less boost and put a smile on your face that you should have had all along. Then, in the off season, try to get that MM intake done.