quote Originally posted by dobey: I'd say strapping an F40 behind an LS3 is well worth the ~30MPG you can get with it.

Is anybody actually getting that with an LS3 / F40 combo in a Fiero? Who? (just curious) If not, what is the best MPG people are getting with an LS swap using the F40?

quote Originally posted by qwikgta: Yea, I guess, I powedercoated it and the mounts for the 282 are welded on now, so I guess the "modify" part of my statement is just that, cutting, welding, painting. Maybe not that big of a deal. As for the driverside frame rail, my concern is that when they mounted my motor/trans, it was put in place for the LS/282 combo. The motor mounts and such were welded in place for that setup. Im worried that if I remove the 282 and install the F40, the LS/F40 will be in the wrong place to use the motor mounts as they are now. So now im cutting/welding all new mounts, moving all the stuff over, even if its a 1/2 inch or so, now im doing a lot of cut/welding on my powedercoated setup. Again, maybe not enough of a issue to do this someday, but I will have to do some additional research, and talk with Archie about it. Rob

FWIW, the left to right location of your engine in the car is the same right now as it would need to be with a 6 speed.

You are right about the fact that the cradle is p-coated very nicely right now & it would be a shame to mess that up with the needed 6 speed mount changes.

Archie

quote Originally posted by Darth Fiero: Is anybody actually getting that with an LS3 / F40 combo in a Fiero? Who? (just curious) If not, what is the best MPG people are getting with an LS swap using the F40?

Jim88GT got 27.2 MPG as stated here: https://www.fiero.nl/forum/F.../HTML/084720.html#p1
I thought it was closer to 30, but 27.2 is pretty good for an LS376 doing 70-80MPH the whole way.

quote Originally posted by Darth Fiero: Is anybody actually getting that with an LS3 / F40 combo in a Fiero? Who? (just curious) If not, what is the best MPG people are getting with an LS swap using the F40?

I know the guy that bought Archies LS1/6 speed car out here in Tx got 27 MPG when I talked to him at the one show he brung it to....

quote Originally posted by qwikgta: As for the driverside frame rail, my concern is that when they mounted my motor/trans, it was put in place for the LS/282 combo. The motor mounts and such were welded in place for that setup. Im worried that if I remove the 282 and install the F40, the LS/F40 will be in the wrong place to use the motor mounts as they are now. Again, maybe not enough of a issue to do this someday, but I will have to do some additional research, and talk with Archie about it. Rob

Ask Archie to send you the f-40 install video It's not an ls engine (looks like an L98) but he doesn't change the motor mounts, only mounts for the trans are installed. He even says in the location video for the LSx installation that the adapter plate is located in the exact same spot for the 5 speed as it is with the 6-speed installations. So really, it's just the trans, following his steps it took almost no time at all. Most "difficult" part was cutting a little "nub" off the LS engine for clearance of the half-shaft (looked like some weird bolt-hole that was mostly obscured by the oil pan, and thus useless).

quote Originally posted by whitey078: Ask Archie to send you the f-40 install video It's not an ls engine (looks like an L98) but he doesn't change the motor mounts, only mounts for the trans are installed. He even says in the location video for the LSx installation that the adapter plate is located in the exact same spot for the 5 speed as it is with the 6-speed installations. So really, it's just the trans, following his steps it took almost no time at all. Most "difficult" part was cutting a little "nub" off the LS engine for clearance of the half-shaft (looked like some weird bolt-hole that was mostly obscured by the oil pan, and thus useless).

Did u get my PM about wanting that 88 motor?

27.2 mpg is not bad at all.

FWIW, that DoD LS4 / 4T65-E swap I did a few years ago got 35mpg @ 55mph according to the DIC/trip computer (DoD system engaged). BUT, that figure dropped significantly the faster you went. I want to say it hovered around 30-31mpg once you got up to 70mph (w/ DoD engaged). Never got a chance to verify this on a fuel tank refill because I didn't have the car that long.

quote Originally posted by Darth Fiero: Is anybody actually getting that with an LS3 / F40 combo in a Fiero? Who? (just curious) If not, what is the best MPG people are getting with an LS swap using the F40?

I am getting 25 to 26 with the AC on. 6th gear is great.

Jack

30mpg is what my friend gets with his automatic ls4, so mechanically an ls4/f40 should do better. The only reason I can imagine it wouldn't would be if you had tuning issues. Sorry I just realized this was about ls3/40 combos.

[This message has been edited by dratts (edited 08-03-2011).]

quote Originally posted by dratts: 30mpg is what my friend gets with his automatic ls4, so mechanically an ls4/f40 should do better. The only reason I can imagine it wouldn't would be if you had tuning issues. Sorry I just realized this was about ls3/40 combos.

Well, the F40 in general, but fieroguru nor I have got our swaps in and running yet, to determine what MPG we're getting. I've deleted the DoD though, while guru is keeping it. I don't know if it'll work too well with the manual behind it. I hope to get upwards of 35 MPG with mine though, to start.

I think the small cube LS engines/F40 combos could easily be in the 30-35 mpg range. A 4.8 with LS1 intake (with EGR) coupled to an F40 would be an ideal daily driver with enough power/torque for spirited drives and should deliver 35+ mpg at 70 mph (maybe more with some ERG tuning). Then if you want more, just slap a turbo on it.

I am hoping the DoD feature will enable 35 mpg on my somewhat stout LS4/F40 combo. After this swap, I will probably do a mild 4.8/F40 swap for my daily driver.

quote Originally posted by fieroguru: I think the small cube LS engines/F40 combos could easily be in the 30-35 mpg range. A 4.8 with LS1 intake (with EGR) coupled to an F40 would be an ideal daily driver with enough power/torque for spirited drives and should deliver 35+ mpg at 70 mph (maybe more with some ERG tuning). Then if you want more, just slap a turbo on it. I am hoping the DoD feature will enable 35 mpg on my somewhat stout LS4/F40 combo. After this swap, I will probably do a mild 4.8/F40 swap for my daily driver.

Agreed. I would totally love to get a 4.8 crank turned down to the same length as the LS4 crank, and shove it in the LS4 block. Would allow for higher revving, and the lower torque would help make the 1st gear in the F40 feel more useful. And it would still be easy to knock 400+ HP out at the flywheel with one.

quote Originally posted by Joseph Upson: The intermediate shaft assembly used on the Chevy Beretta 2.8 might be a better fit in your situation.

got a spare one?

I have one of the earliest 4.9 installs with the F40 and in my opinion all the complaints about ratios are overblown.

People that are looking at spreadsheets and drawing conclusions about drivability should probably keep their opinions to themselves. They honestly don't know what they are talking about.

When I first drove my 4.9/F40 I had a grin from ear to ear and thought "what the BLEEP is all the nonsense about 1st gear about?" And I never once experienced anything between 1st and 2nd to complain about. Now I have 27" tall tires in the back and have a torquey engine, so everyone else's experience might be different.

My only complaint is the rattle in the box at idle. It does quiet out a little at speed but it's slightly annoying. Overall it's worth it to me, compared to any 5 speed, and really worth it compared to any auto.

quote Originally posted by jscott1: People that are looking at spreadsheets and drawing conclusions about drivability should probably keep their opinions to themselves. They honestly don't know what they are talking about.

LOL... I drive a Getrag with 3.50 first and 2.05 second and think "Wow, I hate how much the RPM drops going from 1st to 2nd.". I don't need to drive a transmission with a 3.79 first and 2.05 second to know it's going to be worse.

quote Originally posted by jscott1: People that are looking at spreadsheets and drawing conclusions about drivability should probably keep their opinions to themselves. They honestly don't know what they are talking about.

I am going to bet the people looking at spread sheets and commenting have a vast knowledge on what they are talking about(Will for example). Driving something with an F40 is not going to change what the spread sheets say.

I think you going from the sluggish shitbox auto to the F40 is what gives you such a good impression of it....Or the fact that the 4.9 runs out of breath so fast that you do not get the full effect out of the short first gear....

quote Originally posted by Archie: FWIW, the left to right location of your engine in the car is the same right now as it would need to be with a 6 speed. You are right about the fact that the cradle is p-coated very nicely right now & it would be a shame to mess that up with the needed 6 speed mount changes. Archie

Thanks Arch, good to know that the motor would not have to move.

Rob

The only time the 3.79->2.05 comes into play is when racing...and wanting to keep your car in a power band.
From normal driving, you pull out in 1st to about 2500rpm then shift into 2nd, the rpm drops to 1300ish. Really not a big deal at all with motors with bottom end torque >2.8L... Recall this motor is for a 3900...

Yes, for racing, not ideal but who races everyday?

My 3.4 GT makes 249 ft*lbs of torque and it gets better gas mileage with the 6 speed than my 2.8+5 speed Formula...and that's with me pushing the 3.4 much more than the 2.8...

quote Originally posted by lou_dias: Yes, for racing, not ideal but who races everyday?

<raises hand>
I don't *race* every day, but I didn't build the car to tool around in. One of the most satisfying things for me at the end of a long day at work (and I had a couple that were 20 hrs this week) is to mat the throttle and blast through a few gears. I like it better when those gears are chosen for speed rather than grandma's ability to get the car moving uphill.

Glad you like it. I wouldn't.
The reasons have been rehashed dozens of times. If you don't get it, you don't get it.

quote Originally posted by Will: Glad you like it. I wouldn't. The reasons have been rehashed dozens of times. If you don't get it, you don't get it.

We get it. You don't like it. Some other people don't like it. But every time the discussion comes up and you rehash it with "you are going to hate it because I hate it" then it's no wonder there's always arguments and dissention on the subject.

Unfortunately it's a GM FWD trans, and GM doesn't build FWD transmissions to use as much of the engine's powerband as possible. They build them to get the smaller FWD engines up to the speed limit their target markets are going to drive the cars in, and to get better MPG. If you want a GM car with a trans built to go fast, you basically have to buy a new Corvette. Or you need to look at smaller engines that can rev out to 8K+ and take you to 50MPH in 1st gear on a FWD trans. And you're right, it has been rehashed to death, and none of the senseless arguing is going to change the facts. If you want a 'fast' trans in a Fiero, you're going to have to spend the money to get a race trans built with the gears you want.

quote Originally posted by lou_dias: Yes, for racing, not ideal but who races everyday?

It depends what kind of racing you're doing. For drag racing, yeah the 1-2 drop is pretty harsh, but for road racing or autocross who cares you're never using first anyway. I found the F40 worked great for the autocross courses where I live. I'd launch in first, short shift to second, because we're usually launching into a slalom or corner and not a drag race start, and then leave it in second for the whole race. The course designs and speeds would be different somewhere else but it was well set up for me.

That's what I thought. I don't drive around in first gear, so unless I'm at the drag strip (and I don't plan on competing) those gear ratios won't be of concern to me.

The only reason I am going with the F23 5 spd over the F40 is costs. I will most likely end up with my swap being less that $1000 when all is said an done for the engine and tranny swap. If I had the extra funding available to me i would go with the F40. Also the Clutch / flywheel / axles combo also scares me a little . I have already done my swap using the Isuzu 5 spd and feel very much inside my comfort zone doing the same using the F23.

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88 Formula CJB Arrived Finally. #689 of 1252
Time to start Working TONY!
There are Two kinds of Fiero's : Notchies and Donors!

[This message has been edited by Kento (edited 08-05-2011).]

quote Originally posted by MstangsBware: I am going to bet the people looking at spread sheets and commenting have a vast knowledge on what they are talking about(Will for example). Driving something with an F40 is not going to change what the spread sheets say. I think you going from the sluggish shitbox auto to the F40 is what gives you such a good impression of it....Or the fact that the 4.9 runs out of breath so fast that you do not get the full effect out of the short first gear....

No doubt Will is one of the smartest guys on here and I'm sure he's driven tons of cars, but he's never driven my car. So his opinion on how it drives is pure conjecture. As we say at NASA "One test is worth 1,000 expert opinions"

quote Originally posted by jscott1: As we say at NASA "One test is worth 1,000 expert opinions"

I like that. Can I use it with my customers?

As for the whole ratio thing, are the spread sheets taking into consideration that the final drive ratio is different between all these transmissions being discused? The actual gear ratios mean little without the final drive ratio figured into the equation.

quote Originally posted by jscott1: No doubt Will is one of the smartest guys on here and I'm sure he's driven tons of cars, but he's never driven my car. So his opinion on how it drives is pure conjecture. As we say at NASA "One test is worth 1,000 expert opinions"

The RPM change is only, and ONLY, a question of the ratio between the ratios of 1st and 2nd. Nothing else in the transmission or rest of the car, tire size, final drive, whether your car is blue/white/red/yellow, fastback/notchback or whatever else you think is relevant matters. It's a FACT that the RPM change is greater in the F40 than a Getrag or Isuzu. That is absolutely not conjecture at all.

Whether or not the RPM change bothers you or not is a completely different question.

quote Originally posted by lou_dias: The only time the 3.79->2.05 comes into play is when racing...and wanting to keep your car in a power band. From normal driving, you pull out in 1st to about 2500rpm then shift into 2nd, the rpm drops to 1300ish. Really not a big deal at all with motors with bottom end torque >2.8L... Recall this motor is for a 3900... Yes, for racing, not ideal but who races everyday? My 3.4 GT makes 249 ft*lbs of torque and it gets better gas mileage with the 6 speed than my 2.8+5 speed Formula...and that's with me pushing the 3.4 much more than the 2.8...

While the gap pisses me off during quick acceleration, the Isuzu gap is annoying period.

In slow bumper to bumper traffic, in some critical speed range, sometimes I feel like I'm either lugging in 2nd, or over-revving in 1st. I can't grab the gear I want.

[This message has been edited by pmbrunelle (edited 08-05-2011).]

Ohhh, so it's not that first is too short, but the gap between 1st and 2nd is too big? I see. I think? Still haven't driven one yet.

quote Originally posted by pmbrunelle: The RPM change is only, and ONLY, a question of the ratio between the ratios of 1st and 2nd. Nothing else in the transmission or rest of the car, tire size, final drive, whether your car is blue/white/red/yellow, fastback/notchback or whatever else you think is relevant matters. It's a FACT that the RPM change is greater in the F40 than a Getrag or Isuzu. That is absolutely not conjecture at all.

We are going to have to agree to disagree on this point.

Besides we all know that red cars are significantly faster than any other color.

quote Originally posted by jscott1: Case in point, do you hear anyone with a duke powered Fiero complaining about the 1-2 drop in the isuzu? Not usually. Its when you swap in an engine with less low end torque when they complain.

Less low end torque than a duke? Like a duke with a bad cylinder?

I wouldn't say the Getrag 282 in the Fiero is really any better than the F40, but the 1-2 shift isn't too bad with the 2.8. With an LS4, if I was gunning it out of the box every time, I might end up not liking the 1-2 shift on the F40, since it will get me to 33MPH so quickly. That's at 6000 RPM on stock size tires. But I don't think I'll miss the extra 2MPH the 282 would give.

Nobody with the duke and and Isuzu complains about the 1-2 shift, because you spend so much time in 1st gear it doesn't matter. Some of the gear differences on my Cruze Eco can be annoying, especially at speed on the highway, when traffic starts being unfavorable to cruise control. But I skip gears all the time, and the drops aren't usually too bad. And that trans is by no means built for performance.

quote Originally posted by dobey: Less low end torque than a duke? Like a duke with a bad cylinder?

Believe it or not the 2.8 has less low end torque than the duke. Think about it, it has two extra cylinders with only 0.3 liters more displacement. In other words the duke has 4 big honking cylinders that actually does produce more low end torque than the 2.8. That is why people that swap a 2.8 into a former duke/isuzu car are the main ones that complain about the 1-2 shift on the isuzu.

At the end of the day the 65E auto RULZ!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
But I am itching to get back into a 5 speed car as a DD....While I love the auto for what it is I want a 5 speed for a DD as after 6 years of the auto it is time...

quote Originally posted by MstangsBware: At the end of the day the 65E auto RULZ!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! But I am itching to get back into a 5 speed car as a DD....While I love the auto for what it is I want a 5 speed for a DD as after 6 years of the auto it is time...

x2 I love the auto 1st 53mph@6000rpm

However, I would switch to a F23, the one with the good ratios with a swapped bellhousing.

What is the deal with the 6 speeds anyway? I guess more gears is like more beer, or more girls but after a point the law of dimishing returns kicks in.

quote Originally posted by 1fatcat: Ohhh, so it's not that first is too short, but the gap between 1st and 2nd is too big? I see. I think? Still haven't driven one yet.

That's the big point.
However, I also think that the overall 1st ratio is too short. It's not a "problem" right now as my car keeps traction through first, but there will come a time when it will become a problem.

quote Originally posted by Will: Lol... have dyno charts to verify that? After all "One test is worth 1,000 expert opinions".

Touche' let me see if I can find a dyno chart to back that up.

EDIT -

First the bone stock 2.8 Curves,


Next a bone stock 2.5:



Look at the torque... thanks for calling me out on the data, I was wrong. The duke does not have more low end torque.


What I should have said was that the iron puke reaches it's peak torque sooner and has a flatter curve. So the 1-2 shift doesn't "feel" like such a drop off, whereas on the 2.8 if you let the revs drop the torque will drop off more dramatically and you will feel that.

But this also shows that the grind of the gears is not the only thing that affects driveability. That's why we do the tests.

[This message has been edited by jscott1 (edited 08-06-2011).]

quote Originally posted by nosrac: What is the deal with the 6 speeds anyway? I guess more gears is like more beer, or more girls but after a point the law of dimishing returns kicks in.

The nice OD on 6th gear to net more MPG on the highway.

Going 3 MPH faster in 1st, vs getting 3-5 MPG more, i'll take the latter. Can always shift to go faster.

quote Originally posted by nosrac: What is the deal with the 6 speeds anyway? I guess more gears is like more beer, or more girls but after a point the law of dimishing returns kicks in.

I've been developing a plan to take my car to the Texas Mile... unfortunately work and school got in the way this October, and deployment may get in the way next May, so I might not get to do it until October '12, but...

My current transmission has the 2.19 2nd and 1.03 4th in place of the 2.05 and 0.92 combo that came in the Fiero.
Swapping the Fiero 3.61 ring & pinion in the 282 to 3.94 would significantly improve my standing mile performance.
Changing out the 0.72 5th gear for the 0.81 quad 4 unit would further improve standing mile performance.
However, at that point the car would turn close to 3500 RPM at 80 mph and be well on its way to being too extreme to be nice to drive on the street, as well as losing fuel economy.

With a little mixing and matching from different applications and different years, I can put together an F40 with essentially the same 2nd - 5th and final drive as the 282 I outlined above, but the F40 would have a 0.62 top gear to bring the cruising RPM back down to about 2700 at 80.

[This message has been edited by Will (edited 08-06-2011).]

Edited because of incorrect info....

[This message has been edited by nosrac (edited 08-11-2011).]