Well, I installed the Hellwig LP-25 helper springs on my '91 F-150 and am quite impressed... Wow!!! Stands up, and doesn't sag at all under my trailer. Yee-haw!

Now, I'd like to do *something* to the engine... The 302 is terrible for towing. It struggles trying to accelerate with my 2500 pound horse trailer (headwinds around 30 knots today) and takes forever to get to 65 mph, then won't hold it when cruise is set. If there's a hill, forget it...

I'd imagine the 351 isn't really much better towing... My '98 V-6 was better than this '91 302.

So, what are the first things I should do to this truck to make it pull like a truck should pull? Some sort of intake mods come to mind--the truck feels like it's starving for air. I've heard mixed reviews of the K&N FIPK; seems like I should make a mass air conversion first.

Thanks,

Mike

 

Superchip.

When I had my '93, the chip was the best mod I made. K&N filter and exhaust mods "helped", but not as much as the Superchip when I towed my boat (~3000lbs).

 

I can't imagine that your truck struggles with 2100 lbs? I have an 86 F250 with 351W and I tow a 6000lb camper with it and notice no ill effects. What rear axle ratio do you have?

------------------
86 F250, 351W 4bbl.

 

I gotta go with Bill. I don't think the engine is what is limiting your towing. Gear ratio has a huge effect. My '93, with the 300 I6 with 3.55 gears, will pull that much weight without much problem and its stock hp/trq ratings are lower (of course, who stays stock). The air intake and exhaust mods are worth it - they will give you more power. I'd say that with mine on the 300, I'm getting more power than a stock 302.

------------------
1993 F-150 SWB Supercab 4.9l 4 speed auto w/ OD, 3.55 gears, K&N fipk, Custom Exhaust w/ Flowmaster.

But to chip or not to chip? Hmmmmm...

 

Mike,

I have to agree with the gear ratio change. If it is still stock you will have at the most a 3.55 ratio. For pulling most swear by 4.10's. This depends on tire size, also. The bigger the tires the lower gearing needed. I want to go up to a 3.73 ratio, personally. At my job I have driven a 85'Dodge with a 318 and a low rear that will pull my Ford backwards uphill. Likewise I have driven a high-geared big block that accelerated and towed terribly.
I have the 302 with a 5 spd. I'm glad to know i'm not the only one not happy with towing performance. I have 3.08 gears and it about dies pulling my 1000 pound trailer empty across a decent hill. The one advantage to the 5 spd and high ratio gears is that I can throw it in third and still do 60 or 65 mph. It does fine once I put it in third.
I also have done mods such as a chip, exhaust and a FIPK. All of these helped, but in hindsight I really wish I had put the money toward a gear swap. It's really not that expensive compared to the mods unless you have a 4wd (both pumpkins must be opened and the gears swapped.)
There's no better way to get 4cylinder power from an 8 cylinder than to gear it wrong.
-Hank

------------------
1996 F-150 (3/96-old style)XLT, 302, 5sp. Toreador Red CC, Tow Pkg, Optional Payload Pkg, HD susp., Flowmaster 40 series, "Duals",
Raven Cap, Bumper Guards, Hood Ornament, Unity Lights, Jet Chip, K&N, B&M Shift ****, Hidden Hitch w/ Ford Motorsports Cover,...etc.

 

I have axle code 19, (19N??). Supposed to be a 3.55 rear end.

One thing I have noticed is that I'm getting only about 15mpg. The truck has new plugs, wires, O2 sensor, PCV valve, and EGR valve.
Can't think of any other easy mechanical places to look that might be causing poor acceleration, performance, and towing.

Is 13 seconds about right for a '91 302/extended cab 4x2 making a 0-60 run?

The gearing sounds like a simple enough fix... need limited slip, anyway. The transmission is isolated from the computer, so a chip won't help with shift points and I'm wary of a marginal performance improvement from a chip that requires super unleaded... Maybe performance will increase better than marginal, though... who knows?

Any further inputs will be appreciated--especially thoughts on whether or not this performance is typical of a '91 302. I don't believe that the 351W is *that* much better than a healthy 302 that it can pull a house trailer with ease. This performance just seems odd to me. Engine has 73,000 miles on the clock.

-Mike

 

Other thing is that I'll be pulling a horse from NM to Georgia in about a month and a half...

Want to get this fixed before having to drive all that way with a struggling truck.

-Mike

 

Here are the specs on a 302 vs. a 351.

1991 302 185hp@3800 270ftlbs@2400
1986 351 210hp@4000 305ftlbs@2800
1991 351 200hp@4000 315ftlbs@2800

There is quite a difference, but the weight of your load is not killing your engine. You should be able to tow that weight with ease.

 

Is 45 ft-lbs really much of a difference?
I know the power numbers aren't impressive on any of the engines...

One other thing... Despite the EGR, PCV, and O2 sensors being replaced the check engine light does still come on occasionally.
Maybe once every 2 weeks. I think I've replaced everything emissions-wise that would be causing the light to come on...

If I take this truck to Ford for service, what should I tell them to check, as far as lack of power. 73,000 miles seems a bit low to be in need of a rebuild.

Thanks,

Mike

 

Mike - maybe your catalytic converter is clogged. It happened to one of my mom's old cars and just killed the power.

 

Mike,
I definately think there is something wrong with your engine. I tow a little over 3,000 lbs a lot, and with my 300, have no problem holding speed. Thats with 3.08 axle ratio and in 4th. Definately see what codes you can pull from it. I would be willing to bet something is wrong. Checking the cat isn't a bad idea. Check the cheapest things first is the way I go.

------------------
Rob
89 F150 4X4
300 I-6, 5 spd
For Off Road Driving

 

One thing I forgot is maybe the problem is the torque converter. A bad one of those would completely kill an engine. Maybe just changing to a higher quality fluid and a filter change could help that. Also, maybe a cooler if you don't have one. Or possibly a locking aftermarket one, if the stock one is not. I have a standard, so I don't know much about what you have.

------------------
Rob
89 F150 4X4
300 I-6, 5 spd
For Off Road Driving

 

Nascar bill: I kinda have to argue with you. Torque is what gets you going, and hp is what keeps you going. The hp is whats really needed when keeping a truck going with a heavy load. Yes the 351 is a better pulling engine. But the 0-60 unloaded times are not much different for either of the 2 v8s. The 351 is built for towing. At least from a stock standpoint. I have 2 f-150s a wornout 89 and a great 93. I feel my 93 pulls our 16' car hualer and a load easier than my stock 89, or a stock 351. My buddy has a 92 4x4 with a 351 and a e40d. His stock 351 didn't pull much better than my 89 302. Its all about gears gears gears gears.

Mike: 19 stands for 3.55 and 19n stands for 3.55 ls

I keep my foot on the gas in my 89 302, and it will keep up with the best. Its tired with 145k.

[This message has been edited by Pastmaster (edited 03-25-2000).]

 

In a sense I see your point, but when you you have wind resistance and more weight, you want to be cruising at your peak torque. That is like saying a 240 HP Lightning will tow as good as a 245HP 460. The will 460 will easily out tow the 351.

 

Nascar: Your correct, there is no replacement for displacement when it comes to towing.