It seems as though the turbo discussion keeps going round and round with no actual parts list. I want to buy a 1973-1979 F-truck, and I would really like to have the smoothness of the I-6, but with some pep beyond 2500rpm. I would be willing to drop in a "new" EFI engine or rebuild with a new head just to have something unique on the road. I owned a 1995 F150 4x4 once, and I used to love how I could just let out the clutch without stepping on the gas. Above 50mph; though, it ran out of oomph.

I guess my question is, can the 6 be turbocharged to V8 horsepower, or should I be looking for a V8 instead?

 

Replying to my own post. I should have read ALL of the turbo posts. I still would like to try fuel injection, and I saw very little info on how it could be done. A 1996 MAF engine? What kind of injectors?

 

I am going to fab my own turbo kit. I found a company that has all the parts, but you need to fab it all together. I have an 81 six with a 1bbl carb and I think that it can be done. I haven't heard of that being done, but I'll give it a whack. It seems pretty simple, just harness the exhaust to turn the turbo and cool the air. The univeral kit come with a adapter for the carb. The problem is having to the plumbing. I think that it'll be easier to do on mine since it don't have a computer and I can adjust the fuel mixture. I'll probably replace the intake manifold with a 4bbl intake and get a 4bbl carb too. I should probably start in the summer.

 

Injector choice is driven by how much power you want to produce. 19lb/hr injectors are good to about 300 hp, 24's up to about 400. I would use the 24's because they allow a lower fuel pressure. The easiest way to make it work is with an aftermarket EFI driver from FAST or Speed Pro. It isn't cheap, but it is much easier than butchering a factory harness to work. The factory EFI lower will work very well as a basis for the manifold. If you stay below 4000 rpm you could probably even use the upper with a larger throttle body. If you exceed 4000 rpm you are getting away from what the engine was designed for and the law of diminishing returns applies. You can't pull a plow with a racehorse and vice versa. The 300 is designed for torque production at low rpm, so you can't lose if you try to enhance that.

 

Great, you can get 300hp? All I really want is to be able to match my Triton 5.4 at 260hp. I will very rarely want power above 4000rpm, and I don't want to ruin the bottom end torque by installing a different cam or short intake runners. I feel that the turbo will compensate for the small valves, ports, and short-cam in the head between 2000-4000rpm. The two problems with the injected engine that I gather from this forum is that it is already at its limit on fuel flow, and that the computer doesn't understand a manifold running above atmospheric pressure.

 

 

You can probably get 260 hp without a turbo and still not exceed 4000 rpm. You would need to pull the engine down and do some work internally, but that would still be cheaper than a turbo setup.

The computer won't like manifold pressures above atmospheric, so you install a check valve in the vacuum line to the MAP sensor and run an FMU to compensate. The MAP sensor will read normally as long as there is atmospheric pressure or below in the manifold, but when pressure increases the valve closes and leaves it reading the barometer. The FMU increases fuel pressure as needed to maintain a good a/f ratio.

 

>You can probably get 260 hp without a turbo and still not
>exceed 4000 rpm. You would need to pull the engine down and
>do some work internally, but that would still be cheaper
>than a turbo setup.


Thats possible but would take lots of compression.... At 4000rpm, 260hp translates into 341ft-lbs. Thats a relatively easy number to get for a peak torque, but I don't think you want peak torque to be that high do you?


-=Whittey=-

 

[updated:LAST EDITED ON 16-Nov-02 AT 09:05 AM (EST)]If it was built to make peak torque at 4000 rpm it would be really foolish not to wind it any tighter than that. An engine that develop peak torque at 4000 usually makes peak power up around 5500-6000. It should be relatively easy to get about 370 ft-lbs and 260 hp out of a 300. If you plug a stock cam into DD2K with 9.5:1 compression, small tube headers, ported heads, and TPI intake @ 750 cfm it spits out 242 hp @ 4000 rpm and 352 ft-lbs @ 2000. The torque curve is already dropping off at 2000 rpm, that's just the lowest rpm it graphs. Stock lift and duration ground on a 109 LCA and with 1.7 rockers was 353@2000 and 258@4500. Substituting a hydraulic roller cam with stock specs upped it to 383@2000 and 279@4500. Any of these combinations would be awesome on the street, trail and anywhere else, and wouldn't require anything exotic or custom built.

No, I don't believe everything DD2K tells me, but it's usually in the ballpark. And I've also noticed on the Ford stuff it is usually a little conservative anyway. The GM engines are pretty much dead on.

 

What is DD2K, sounds like a program where you plug in theoretical performance parameters.

 

Desk Top Dyno 2000. It is a useful tool to try out different concepts, but its accuracy is sometimes not what it could be. It is very accurate on the small block Chevy. I built an LT1 for a 97 Z28 and DD2K was within 2 hp of the actual dyno numbers, the graphs looked identical. I also have a combination for a big block Ford that made 813 hp and when that combination was plugged in it only showed about 720. As good as it is, it assumes a lot. It doesn't ask anything about timing curves, chamber shape, rod length, etc. and these all have a huge impact on output. It seems like it works well on budget street engines, but gives up a little accuracy when power levels go up.

 

DD2K is fun! After I finished the run on my engine, I played for a while. Can you imagine a 500hp, turbocharged, NOS injected 1 lunger?
The thing I don't get is they say my engine is still making power at 6500rpm. Even with the forged crank, it would have blown by then. But another interesting thing I have found is that a stock-profile cam is perfect for a turbo. It was making 350 hp, and 410lbs of torque at 8psi of boost! Change the cam, and it goes away. Just some food for thought.

Jared

 

That's one of the reasons DD2K is just a play toy. It doesn't evaluate the parts combination for practicality. The is a more complex program out there called Engine Analyzer. It costs several hundred dollars, but it evaluates everything. If there is a possibility of a nasty valvetrain harmonic, it tells you. If a component doesn't match the rest of the combination, it tells you. One cool thing about DD2K that other programs don't have is optimization. Unfortunately, it isn't powerful enough to be completely accurate.

 

> If you plug a
>stock cam into DD2K with 9.5:1 compression, small tube
>headers, ported heads, and TPI intake @ 750 cfm it spits out
>242 hp @ 4000 rpm and 352 ft-lbs @ 2000. The torque curve
>is already dropping off at 2000 rpm, that's just the lowest
>rpm it graphs. Stock lift and duration ground on a 109 LCA
>and with 1.7 rockers was 353@2000 and 258@4500.
>Substituting a hydraulic roller cam with stock specs upped
>it to 383@2000 and 279@4500.

wow, thats impressive for an inliner. id be happy with 200hp and 300ft-lb any ideas to get this WITHOUT tearing the engine down? i was thinking a ported head along with my k&n/homemade cold air kit and exhaust (2.5" from 1st cat into a flow 40 series delta flow) would get me near me hopeful numbers. yes? no? maybe? anyone?

 

Just for kicks I plugged my engine in and got 187 hp @ 3500 and 328 ft-lbs @ 2000. It actually suggests more torque before 2000, but the graph doesn't go that low. Those numbers are pretty close to what I had calculated based on my drag times and vehicle weight. Add some 1.7 roller rockers and I should be at around 205/350