2.9 Power

[Twister]

This thread is not what the title suggests. I am part of a Bronco II group on facebook and someone asked about getting more power out of a 2.9L. So this guy posted that he rebuilt his 2.9l, had the heads shaved .01 and added free flow 1 3/4 tube headers. He is claiming he got 197 hp and 250 lb ft of torque at 4000 rpm at the wheels on the dyno. I think he is posted some BS, but i am not that knowledgeable with engines that much. Is this even possible? I would think if getting that much power out of 2.9 was that easy people wouldn't swap them out so fast.

What do you guys think

 

[Schnot]

Dynos lie a lot. Like a lot.

Have him post pics, or it didn't happen.

 

[lil_Blue_Ford]

It's been discussed at length before....

It is possible to build up a 2.9 to get performance like that or more. But it becomes cost-prohibitive really quickly since there was never really an aftermarket for the 2.9L motor. You can bore it out, have a custom set of crank and cam shafts done, port and polish the intake and exhaust, run a Scorpio intake (twin throttle bodies FTW), put 4.0L valves in the heads, convert to a MAF system over the factory speed density, headers, etc.

But the bottom line is that unless you have use of a machine shop and it's just a labor of love to play around with, the expense of having all that sort of stuff done to build it up easily becomes greater than the cost of stuffing a 302 under the hood and calling it a day.

That said, a good full-on tune-up of a 2.9 can do wonders for how well it runs - I'm talking fuel filter, air filter, oil change (throw a cup of ATF in there while you're at it), plugs, wires, cap and rotor, TFI module (they're often bad, Autozone will test them for free), etc. I swapped the larger throttle body on the 2.9 that is currently in my choptop and it does pretty decent like that. I have an intention of pulling the motor and swapping it for the 4.0 in my 88 that I never got around to wiring up, while I have the 2.9 out I'll throw a set of headers on it and probably do a MAF conversion because I was able to pick the parts up for cheap. Do I expect mad horsepower gains? No. But it will probably run a little more efficiently and that's all I'm really after.

 

[disciplerocks]

Or he could have spent half the money and a quarter of the time and just swapped in a 4.0.

 

[straycat]

I swapped out the cam with a roller cam and rockers and port and polished the heads and got a bit more power and torque on my 83 ranger 2.8 and I did the same with my 89 BII 2.9 motor. The power was much better and it only took me 2 days to do the work and had them back on the road and wheeling again. I could tell the difference when towing my bike trailer or one of my boats. The 4.0 motor is the best motor for a stock motor. If I had another Ranger or BII with the smaller motor I would do a 4.0 swap now a days.

 

[Hahnsb2]

So this guy posted that he rebuilt his 2.9l, had the heads shaved .01 and added free flow 1 3/4 tube headers. He is claiming he got 197 hp and 250 lb ft of torque at 4000 rpm at the wheels on the dyno.

He's extremely FOS.

 

[bigfatloser]

Or he could have spent half the money and a quarter of the time and just swapped in a 4.0.

Seems to be the typical answer for trying to build a 2.9 on this board.

 

[adsm08]

I believe those numbers can be had from a 2.9, but it will take a lot more work than that.

 

[adsm08]

Seems to be the typical answer for trying to build a 2.9 on this board.

When I knew nothing about cars other than the basics I came to the conclusion that it is less work and money to put a 4.0 in than to build any real power out of a 2.9.

This was when I still though I could up performance on a 2.9 by installing a coil pack.

 

[disciplerocks]

had the heads shaved .01

This also would have been pointless. Basically just shaved enough to make sure they are straight. If actually wanted gains out of a decked head, you need to be in the 0.040" or more range. Depending on piston to valve clearance.

 

[RustedRanger]

1 3/4 headers would make a 2.9 fall on its face on the low end....197 hp at 4,000 also shows it's BS....you need to spin a smaller motor faster to make power if it's not turbo'd or supercharged. Horsepower is always measured from torque....power graphs always show the same HP and TQ at 5,250 RPM so that means the HP would rise from 4,000 and the TQ would drop until 5,250....if it made more HP I think he would've claimed that figure.....

 

[85_Ranger4x4]

Seems to be the typical answer for trying to build a 2.9 on this board.

Just a fact of life

About 10 years ago a guy on here mixed and matched a 2.8 and 2.9 and came up with something like a 4.3 out of it. He said it ran pretty good. He had a ton of work and $$ in it though...

 

[MJ'sBlkBII]

This was when I still though I could up performance on a 2.9 by installing a coil pack.

The heck you say?! Yeah, and next you claim there's no Big Foot or Loch Ness!

 

[Twister]

So general thought is the guys I full of shit. I asked him to post dyno papers and he has yet to respond.

Sent from, wait how did this get here?

 

[MJ'sBlkBII]

My vote is yes, he is. Somewhere a few years back I came across a guy claiming 200 hp from a OHV 2.9, with forced induction. Not sure of his validity either. Where is the porting for the intake? Without significant change to air in, he isn't getting that kind of change out. Know what I mean? My old 80" Evo Harley has bigger bores and uses 1 3/4" header pipe.