fieroguru

iTrader: (1)

The LS4/F40 Fiero has been mostly parked since early November. There were a few weekends where the temps were over 50 and I took it out for a spin. The car is always a blast to drive!

Haven't done much with it as most of my free time is making parts for the 2nd swap.

I have decided to start working on another upgrade before adding the turbo. I picked up a Ford PTU AWD unit and will be redesigning the housing to flip the output so it will go under the oil pan and toward the front wheels.

Capt Fiero

okay now I think you have officially gone off the deep end and are nuts. Ninety-nine times out of 100 when someone suggests doing an all wheel drive Fiero I ignore the post as I know it will never go anywheres as they cannot fathom the sheer work involved. However after following this thread for so long and seeing the quality of your work I am sure you are completely aware and completely capable of completing the swap conversion. It will be absolutely insane and will take a mechanical genius to pull it off. My only caveat to you regarding this is the Fiero is already getting extremely light in the front end on heavy acceleration especially with the addition of a Turbocharger at some point. I don't believe there will be sufficient front wheel traction to overcome the additional weight you are going to introduce to the car in a straight line acceleration scenario. It will however turn the car into a bullet on a road course.

fieroguru

iTrader: (1)

Yeah, I fell off the deep end a long time ago. Maybe AWD will help me claw my way back out.

fieroguru

iTrader: (1)

Started working on the custom mechanical water pump that will work with the custom coolant housing on the previous page.

Capt Fiero

Is there a reason you are going with a mechanical water pump vs the electric? With the Fiero, having the ability to run the pump and circulate water after the ignition is shut off, is a huge benefit if you are involved in a racing environment where you go from WOT track, back to the pits and typically shut the car off just mins after racing. I am going to carry my jump box with me, so I can leave the radiator fan and water pump running for a short time after I shut the car down. For "Street Use" the electric pump being able to run at full speed even when the car is at idle in traffic also seems like a major benefit to me. Plus the simple fact of not having a pump hanging on the front of the engine gives you more room and a much less complicated belt routing. These are just my humble opinions. I still look forward to seeing your designs, as even if I don't agree with it, I always appreciate the workmanship in it.

fieroguru

iTrader: (1)

I have never been a fan of electric water pumps. I have used them before and worked on others cars with them several times.

1. Noise, nearly all had a high pitched whine right behind the passenger seat that got annoying very quickly.
2. Availability. When the pump goes bad, they are not stocked items at local parts stores. One swap we tried to replace the pump due to age, but the mfg was out and it was going to be 6 weeks before we got a replacement.
3. Minimal benefit at low engine RPM. With a thermostat, at idle and low rpm cruise, the thermostat will limit flow, so having a constant 50 gpm from the pump doesn't help (and might prematurely fail the pump motor).
4. At higher RPM and with the thermostat wide open, a mechanical water pump will often exceed the constant flow rate of the electric pump.

Unless you want/need to free up some extra hp at high RPM, or need to run an electric pump due to space considerations, I would much rather stick with a mechanical pump that is readily available at parts stores nationwide.

AAIIIC

iTrader: (19)

With that said, are you using adapting a mechanical water pump from some other application in your custom pump setup?

fieroguru

iTrader: (1)

Yes. I am using what I call a water pump insert from an OEM. The insert is small and compact and fits within a custom machined housing.

Back when I ran a SBC in my fiero, we used a 3.4 V6 water pump insert in the backside of a SBC water pump housing. It required some machine work to the SBC housing and an adapter plate, but it worked quite well and allows the belt drive to be right up against the timing cover for clearance to the frame rail. In the picture below the SBC water pump impeller is on the right, the 3.4 one on the left.





Here is the older version when I ran a v-belt:


For the LS4 mechanical water pump I am using a similar OEM water pump insert, but not the 3.4 one as it is too long. Here is a picture of it sticking through the backside where the coolant inlet will be.

fieroguru

iTrader: (1)

Just a little update, The swap has been done for over 5 years now and past the 46K mile mark. For the past few weeks I have been driving the car daily and took it several times on my commute to Chicago. My last trip to Wisconsin Dells I averaged 28 mpg @ 80 with the engine turning just under 2100 rpm... I really like the 3.09 final drive.

A couple months back I picked up an AWD unit for a F40 transmission and pulled the guts to mock it up. I need to flip the output shaft 180 degrees so it will go under the oil pan so I can have AWD. Just need to make a new main case half...


Not much time for anything else right now...

Capt Fiero

I still think you are mildly crazy for trying it. I've only heard of one other AWD Fiero and they sorta cheated, by driving the front end via an electric motor, and running the rear on gas. IIRC I thought they used some sort of Chevy S10 front IRS setup.

ryeguy2006a

iTrader: (27)

That will be so sick! Where are you on the turbo swap?

fieroguru

iTrader: (1)

The more I thought about the turbo and getting the power to the ground in a semi-safe manner (I don't need wheel spin at 60+ mph), the more I came to the conclusion that I should do the AWD conversion first, then add the turbo bits. So the turbo stuff is just sitting around waiting its turn.

I have nearly settled on this placement for the turbo. The wire structure is the stock Fiero trunk.

ryeguy2006a

iTrader: (27)

That makes sense. I've always loved this build, such an out of the box build.

Capt Fiero

Something I have been thinking about, oil scavanger pumps. With the turbo that low, you are going to need some sort of scavanger pump. Any idea which one you are going to choose?

fieroguru

iTrader: (1)

The turbo drain is still above the pan and with a large enough of a drain tube, I should be able to get by w/o a scavenge pump... especially if I bat wing the pan under the axle and below the turbo...or at least that is the plan for now. The AWD unit will make this a little more of a challenge.

coothethird

I've lurked and watched this build for years now. I must say it is excellent.

I have been thinking about this combo (ls4 + f40) for other possible mid engine toys. Along the way I had many questions. You have answered almost all of them with this build. Thank you for that. Since I still have a couple, I might as well ask you. 1) what is the overall length and width of the ls4/f40 combo? How much clearance (width wise) would you recommend for maintenance/repairs/belt replacement? What is the distance from the centerline of the axles to the front (or rear) of the engine/trans assembly? Would you recommend getting the taller (diesel?) Gearing fitted from the get go?

Apologies for all the nagging questions, but inquiring minds must know!

Thanks again!

fieroguru

iTrader: (1)

Thanks for the compliments!

Here are some key dimensions that will help determine fitment:

• LS4 is 23 3/8" from the bellhousing face to the front face of the balancer
• F40 is 13 7/8" from the bellhousing face to the edge of the transmission case
• Overall drivetrain length (width in a transverse layout) is 37 1/4"
• Axle C/L to crankshaft C/L is 7 3/16"
• The differential housing extends 5 1/4" past the axle C/L to the rear of the car
• The stock LS4 front manifold w/o heat shields extends about 13 3/16 to the front of the axle C/L
• This would make the LS4 25 5/8" wide (exclusing the stock LS4 water pump impact as well as the factory rear exhaust manifold - both of these can be removed/replaced)

Every Fiero based swap of the LS4 requires relocating the alternator (interferes with the strut tower), moving the upper most idler by the water pump (interferes with the firewall) and addressing the coolant fill interference with the decklid hinge box. Other applications could also have clearance issues with the hose connections to the LS4 water pump manifold and the rear exit of the factory exhaust.

The 3.091 final drive is great upgrade for applications that run tires shorter than 26" tires and where the car weighs less than 3000 lbs.

• First gear of the F40 is 3.77.
• First and second gears are cut into the input shaft and there are no numerically lower options available aside from getting a custom input shaft made.
• Stock F40 final drive for the model that bolts to the F40 (MT2) is 3.55.
• This means your launch ratio will be 13.38.
• With 325 flywheel tq and a sub 3000 lb car... this is wheel spin city, which can be fun, but hurts acceleration. To put this into perspective, this would be like running a 5.03 rear gear with a 2.66 T56 or 4.50 rear gear with the 2.97 T56.

The 3.091 upgrade reduces the launch ratio to 11.65. This is like running a 4.37 rear gear with 2.66 T56 or a 3.92 rear gear with a 2.97 T56, and this is still with a sub 3000 lb car.

With a 7000 rpm shift point and 24.8" tires, with the 3.091 final drive the max speed by gear becomes:

• 1st: 44 mph
• 2nd: 82 mph
• 3rd: 127 mph
• 4th: 176 mph
• 5th: 220 mph (Cruise: 1819 rpm @ 70 mph & 2079 rpm @ 80 mph)
• 6th: 269 mph

If you wanted to start mixing and matching final drive ratio as well as gear ratios for 3rd-6th, there are quite a few options.

fieroguru

iTrader: (1)

It has been about 9 months since the last progress update... The car has now been running with the swap for 6 years and 48K miles. My day job has me traveling 3-5 days almost every week, so free time for upgrades has been limited...

The primary upgrade in mid 2018 was adding Addco swaybars front & rear. They had been discontinued, but a guy put together a group buy of 10 front and 10 rear bars, which I participated in. I setup a test fixture to measure the torsional resistance for the stock and Addco bars.

• Stock Front: 169 lb/in (Addco spec'd @ 157 lb/in)
• Addco Front: 243 lb/in (Addco spec'd @ 240 lb/in)
• Stock Rear: 75 lb/in (Addco spec'd @ 81 lb/in)
• Addco Rear: 136 lb/in (Addco spec'd @ 139 lb/in)

Besides the sway bars, I was mostly collecting parts for the next round of upgrades:

• Everything for DoD elimination
• Turbo camshaft: 219/223 .617/.595 LSA114+3 to replace the DoD N/A one: 224/231 .564/.575 @ 113
• Dorman LS2 intake to replace the current LS2 intake (clearance patch for DoD connector won't hold boost).
• Flex Fuel conversion parts

I have been waiting for the past 2 months for a nice 45+ degree day to put the car on a local dyno to get the current baseline. Since the last dyno run 6 years ago, I have moved 350 miles from the dyno, swapped wheels, changed final drives, and put 48K miles on it. So I want to baseline the current setup with a local dyno to see what the gains are from the next round of upgrades. Sadly between poor weather, my travel schedule for work, and the dyno schedule, we haven't been able to get the baseline run done...

The plan for 2019 is to get the parts above installed and replace several mild steel brackets with aluminun to start reducing weight. While the engine is out, mockup the spare LS4/F40 drivetrain in the chassis for the new accessory drive and position the turbo (won't be installed until 2020 most likely). This is the water manifold I plan to run in 2019 with an electric pump.



Here is the new layout for the accessory drive:


Eventually I will integrate it with the mechanical pump previously shown in the thread.

ryeguy2006a

iTrader: (27)

Always love seeing the updates to this build. I love building classic cars, but since my Camaro is nearing completion I may keep an eye out for a good price on a Fiero. I've always liked the idea of a Northstar swap, but the LS4 is likely a more powerful and easier to upgrade swap.

NSFW

Fantastic build. Looking forward to seeing where you take it next.