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Discussion Starter · #1 · (Edited)
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I just started a new project which consists in removing the AC compressor and replacing the heavy stock harmonic balancer / crankshaft pulley with a lighter chromoly pulley that was developed by TTV Racing for a Duratec project with Ford. I trust it’s light but not too light as some alloy pulleys might be.

The pulley has a single 6-groove race and drives the accessory belt approx. 20% slower than stock, so the alternator and water pump will rotate that much slower and induce less drag / less power losses, and less rotational inertia. The crank pulley alone is about 1.4kg (3lbs) lighter than stock.

I have to convert the entire serpentine path to the new 6-groove belt which means new idler pulley, new tensioner pulley, and new alternator pulley. Curiously, the water pump already has a wide pulley but I’m replacing it with a light alloy version.

The AC compressor is a heavy beast and the stock crank pulley is quite heavy too, so together with the condenser and some piping there will be a gain of at least 15kg or so, including approx 2kg of rotating masses between the lighter crank pulley and a new light water pump pulley as well as the removal the AC pulley and its belt. That’s significant as far as inertia, as the crank pulley obviously rotates at engine speed while the water pump and AC pulleys rotate even faster. There is also a general theory about cavitation in water pumps which may or may not be an issue on the EcoBoost, but slowing down the pump gives some headroom for more RPMs.

Together with the reduction of rotating masses, the underdriving also free up some actual ponies. So it’s free horsepower and less engine inertia, to accelerate the car harder, and a bit less “regular” weight too, by removing some of the AC components. The main drawback is less comfort during hot days.

I’ll post the part list once the conversion is sorted out.
 

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Discussion Starter · #3 ·
i guess you enjoy a cool climate :D. keep us updated
Yes I agree that's a step closer to frankensteinisation :)

I live in moderate climate and I use the AC maybe five days a year, and carry the weight the other 360. The good thing is it's easy to undo.
 

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I had done this on my EG Civic before.

AEM and unorthodox racing pulleys ..... it helped especially on the under powered motor.

Post your updates 👍
 
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Did you actually finish this project? If so, how did it turn out?

Yes I agree that's a step closer to frankensteinisation :)

I live in moderate climate and I use the AC maybe five days a year, and carry the weight the other 360. The good thing is it's easy to undo.
 

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Discussion Starter · #6 ·
It got postponed. I had to put the engine back together and the pulley would not have made it on time. The manufacturing partner has the CAD design and was/is ready to cut the two prototypes we planned by I guess it will have to wait until I work on the engine again.
 

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Well if you start it up again keep us updated. My AC just died and I'm debating deleting instead of repairing.

It got postponed. I had to put the engine back together and the pulley would not have made it on time. The manufacturing partner has the CAD design and was/is ready to cut the two prototypes we planned by I guess it will have to wait until I work on the engine again.
 

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Discussion Starter · #9 ·
Well if you start it up again keep us updated. My AC just died and I'm debating deleting instead of repairing.
I sure will. What I did not mention on this thread is a moved away from the 6 rib belt and designed a lightweight 4 rib pulley that uses the stock belt.

I figured that would be much easier than change everything on the belt path: although I have the hardware on the picture the tensioner and idler pulley must somehow be adapted, and the clutched pulley on the alternator changed.

The final 4 rib pulley has 20% under drive and all is needed is a shorter belt, which is easy to find.

This is one of the intermediate designs I made for normal drive / stock belt. I got quotes all over the place from $300 to $3000 for the prototype.


352428

352429
 

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Just a thought on those thinking of deleting the A/C:
I did that on another vehicle that I owned as I modded it to a performance vehicle. Not only did I have strife from my wife over the following years for no A/C, but it was a large issue when selling the car 15 years later. Buyers love performance cars, but they want the creature comforts too!
 

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Discussion Starter · #11 ·
True :) You can still keep the AC piping in place and store the removed parts for that elusive sale in 15 years.

It would not be too difficult to design a lightweight pulley to also underdrives the A/C but again a tiny batch would be expensive, and I’m not sure there is enough demand to risk making a larger batch to drive the cost down, and there are two product variants already.

That’s the dilemma of the small makers right there: you cannot drive cost down without volume and volume implies high upfront costs and risks. Many small fabs make one tiny initial batch sold with thin margins and wait until there is enough back orders to justify a second batch = perpetually out of stock.
 

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Not sure that removing AC is a good idea, you will regret it as soon as you get stuck in traffic during a hot summer day. This is not a joke, you're like in a tin can without an AC, when the outside weather is hot, it feels like hell, I already experienced it for myself. I had to be at a meeting, and when I finally arrived, I was in sweat from the top to the bottom of my body. I am lucky that the experts from antonybatty.com did a great job at the conference, and explained the business plan in details, and I wasn't required to give any additional details.
 

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Not sure that removing AC is a good idea, you will regret it as soon as you get stuck in traffic during a hot summer day.
Yea its a dumb idea. Most owners would be better off cutting back on the burgers and fries, hitting the gym and staying cool in the summer traffic, lol. Then again people order their cars with a sunroof, go figure.

Ciao
 

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Yea its a dumb idea. Most owners would be better off cutting back on the burgers and fries, hitting the gym and staying cool in the summer traffic, lol. Then again people order their cars with a sunroof, go figure.

Ciao
I hate my sunroof...lol. so pointless.
 

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Me too! No option to not have one in canada. Really want to do the carbon roof, but haven't found anyone who has done one before.

Sent from my SM-G986W using Tapatalk
Yes, I cannot for the life of me understand the attraction to sunroofs. I was forced to have one in my Monaro CV8-Z
(Pontiac GTO to Americans) and it was the most pointless thing I've ever experience AND reduced the head room by
1&1/4 inches. When cars got a/c sunroofs became obsolete, same as convertibles really.
Ciao
 

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Yes, I cannot for the life of me understand the attraction to sunroofs. I was forced to have one in my Monaro CV8-Z
(Pontiac GTO to Americans) and it was the most pointless thing I've ever experience AND reduced the head room by
1&1/4 inches. When cars got a/c sunroofs became obsolete, same as convertibles really.
Ciao
Not to mention, they eventually leak too...
 

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Being 6'5", I feel pretty closed in without a sunroof, I'd pay another 20-100$ for a new seal if it ever leaks. It's also nice if you are a smoker, which I'm not.
 

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RS's with sunroofs make the limited selection of available ones even more challenging. I was about to drive to another state to check one out, then they said it had a sun roof. Luckily I found one locally. My issues with it (as many have said) is lack of head room, especially with a helmet, but also the weight. In my other car I had a project that got put on hold, but I had gotten a junk yard sun roof panel, removed the glass, and cut/shaped a piece of tinted polycarbonate. If I recall correctly, the original panel was 22lbs and the one with the poly panel was about 7lbs. That's a lot of weight at the top of the car.
 

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I've always personally liked sunroofs. Having an all black interior, I feel it brightens it up a bit. Like @jefferysanders said, kind of makes me feel shut in without one. Oh, and I'm 6'2, and have plenty of room when wearing my helmet during autocross. If it ever starts leaking, I'll just replace the seal like anything else that starts to go on the car. Then again, not like this car ever sees water anyways... Other than when I wash it of course. 😉
 
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