a few quick turbo questions

[XPC66]

As I said before, there is more of a temptation and a tendancy to get into the loud pedal when it actually does something. It is probably this that makes fuel consumption go up after a car is turbocharged.

Gotta take the human factor into consideration

and that lead foot is obvious when you take a car like the VL Commodore with the Nissan RB30ET and the auto model officially gets 0.5 litres/100km better efficiency than the manual. The same cars with the non turbo RB30E goes the other way with the manual 0.5 more efficient than the auto

 

[XPC66]

well this conversation has so far been pretty interesting. I'm going pretty much with the theory that when i install a v8 rear end and a 3.03 i will probably end up with taller gears as it is (i'm 90% certain i have a 3.5 rear end right now) so that will help a bit in mileage, well theoretically.

I've gotta get this thing broken in though (almost done), and that 3.03 installed soon though cause i keep getting people who want to race it from stoplight to stoplight.

So far a GMC envoy learned not to mess with it on a stop light run, and some teens in a station wagon got embaressed when jumped off the line ahead of me (they had an automatic, and i didn't know they wanted to race), long story short my falcon caught up with em pretty quick.

darn though i'm just so worried i'm gonna fry that 2.77. My dad split one in half with a 144 powershifting it when he was my age.

Another question though for you guys to give an opinion on. What sort of methods do you recommend for making the manifold accept it? I know that chrysler guys just splice the manifolds togethor, but i've seen some ways on it here. The two i can think of would be a J-pipe (which i don't fully understand) or a direct mount (looked simple, but wouldn't heat be a problem?)

Final gear reduction on a turbo car is often in the order of 103% or so of the NA equivalent with same gearbag

This guy has the right idea

 

[Lazy JW]

As I said before, there is more of a temptation and a tendancy to get into the loud pedal when it actually does something. It is probably this that makes fuel consumption go up after a car is turbocharged.

Gotta take the human factor into consideration

Agreed. But still doesn't explain the discrepancy in BSFC.
Joe

 

[Lazy JW]

As I said before, there is more of a temptation and a tendancy to get into the loud pedal when it actually does something. It is probably this that makes fuel consumption go up after a car is turbocharged.

Gotta take the human factor into consideration

Agreed. But still doesn't explain the discrepancy in BSFC.
Joe

 

[wallaka]

a J-pipe (which i don't fully understand)

Nothing complicated about it.

 

[rommaster2]

a J-pipe (which i don't fully understand)

Nothing complicated about it.

Is that bung for an oxygen sensor? Other then that you're right, nothing complicated .

 

[XPC66]

As I said before, there is more of a temptation and a tendancy to get into the loud pedal when it actually does something. It is probably this that makes fuel consumption go up after a car is turbocharged.

Gotta take the human factor into consideration

Agreed. But still doesn't explain the discrepancy in BSFC.
Joe

The widely circulated BSFC figures touted on the net aren't necessarily bible. What is the BSFC for the Falcon 200 six? What is it when it has a hairdryer attached?

In so far as actual fuel consumption BSFC shouldn't come into it when comparing say a turbo 2 litre rated at 100kW@3600 and a 3.6 litre rated at 100 kW@3600.

 

[Lazy JW]

...

The widely circulated BSFC figures touted on the net aren't necessarily bible...

Ok, tell us what the real numbers are. The numbers I quoted came from folks like David Vizard. I am seriously doubting the statement that turbocharging improves fuel economy, and thus far I have seen no evidence to disprove my doubts.

I dunno what the BSFC of a Ford 200 is, but I have before me an article on a 1950 Willys F-Head four-cylinder engine that delivered BSFC of .495 lbshp-hr. I also have data on tractor engines from the 1940's, 50's, and 60's that show BSFC right at .50 lbs/hp-hr. These are real numbers, delivered in real dyno testing with real engines that were available to real people.

I am very interested in improving fuel economy in the real world. Due to limited resources I cannot afford to chase theoretical butterflies, but if turbocharging the White Ox would help my fuel economy I would seriously consider it.
Joe

 

[XPC66]

Well if you have doubts, don't do it. I can only go on the numerous cars I have retrofitted and the outcomes of other guys cars I have been involved with. It would be silly of me to give you a guarantee, because there are too many uncontrollable variables and too few constants. Just the mapping process will differ across tuners as will dyno methods.

If you are happy with the likes of Vizard then stay with his findings and don't put yourself through the heartache. I tend to dismiss most of what those guys have published (except of course the bleeding obvious that is supposedly a revelation, but every petrol head knew way back in the early 20th century), until I have actually performed a modification. So far the degrees of freedom from what is supposedly set in stone and what I have imperically tested are fairly liberal. This is bourne out by the ever increasing power and efficiency indices of production engines = nothing is finte.

About the only real way to get maximum fuel economy is to make sure the engine isn't overpowered for the mean load, otherwise that excess available torque will translate into increased acceleration which will in turn translate into increased consumption rate. Pedal discipline is a weakness.

 

[Lazy JW]

....
About the only real way to get maximum fuel economy is to make sure the engine isn't overpowered for the mean load...

Oh.....I think I have that criterion pretty well handled :roll:

Anyway, I have always assumed that higher BSFC numbers indicated poorer fuel economy (under those conditions) and since no one seems able to produce data showing that turbocharging improves BSFC it seems safe to say that it does not, at least in general terms. YMMV.
Joe

 

[XPC66]

Well I guess even if I posted my figures you wouldn't believe them, so stay with that thought. One thing for sure, if you modified your engine to approach the power levels of 8 psi boost, you'd be able to use the petrol gauge to see how far you had travelled.

You want better economy, go fuel injected with closed loop. That should yield a 17% drop in BSFC at peak VE and 13% mean drop. If you have a low comp engine, increase the comp ratio.

BTW my rough average figures for an injected turbo engine without the haidryer are: idle 0.59, peak torque 0.47, peak power 0.51. With turbo: idle 0.55, peak torque 0.44, peak power 0.49. How do I know this? Because I do maps for both conditions to evaluate compressor curve effectiveness

I spent a lot of my youth on bloody tractors. At 12 years old I was put on an old Fordson Tractor with the pushrod throttle and proceeded to wrench every bone in my body, sprain my thumbs and jar my neck. Several years later I was presented with an International complete with power steering. Two weeks solid scarifying was sooo much easier. 8)

 

[Lazy JW]

....

BTW my rough average figures for an injected turbo engine without the haidryer are: idle 0.59, peak torque 0.47, peak power 0.51. With turbo: idle 0.55, peak torque 0.44, peak power 0.49....

Thank you, that is precisely what I was asking for Looks like modern technology can outperform the 1950 Willys F-Head by a small, but measureable, margin. Reckon what could the Willys do on a level playing field with modern engine control management
Joe

 

[XPC66]

I'm not familiar with your tractor, is it diesel or petrol?

 

[Lazy JW]

The Willys F-Head was used in cars and Jeeps, not tractors, and were gasoline fueled. It had 7.4:1 compression as tested. Sorry about the confusion.

I own a 1941 John Deere Model "A" All-Fuel tractor also but was not refering to it in this discussion.
Joe

 

[fb71]

The Willys F-Head was used in cars and Jeeps

"Go-Devil" !!

 

[XPC66]

The Willys F-Head was used in cars and Jeeps, not tractors, and were gasoline fueled. It had 7.4:1 compression as tested. Sorry about the confusion.

I own a 1941 John Deere Model "A" All-Fuel tractor also but was not refering to it in this discussion.
Joe

OK so something like this?

 

[Lazy JW]

Yup, that's it. Nothing spectacular, just a cheap way of upgrading their flathead without a complete re-tooling. I used to own a couple of them.
Joe

 

[XPC66]

It's beaut design = I bet you couldn't kill it with a stick. Where's the spindle?