Which pulley
- Thread starter SAGT
- Start date
tmcphail
GT Owner/Vendor
tmcphail
GT Owner/Vendor
MAD IN NC
Proud Owner/ BOD blah bla
You can even get a 100 octane tune for the 2.7 pulley.
But I'm worried for ya as it sounds like you have become "your tuners" guinea pig to learn "real time" on a Ford GT. Careful here - the FGT engine is not the same as the GT500.......
Cost $30K more in actuality......
You are a braver man than I am. I would have just written Torrie a check in that it is a proven tune. :cheers
Good luck!
Thugboat
GT Owner
If you are worried about using someone Local, Torrie can even e-mail it to you. I still shake my head over that one!!! Give him all the specifics and it will be custom to your car!
Larry
Larry
- Dec 21, 2009
- 83
I appreciate your concern. Jon Lund is my tuner. He is one of the most respected tunners on the planet especially with the Ford mod motors. The Ford GT is his favorite car to tune. My car is by no means his first. He has already tuned mine once. He will burn me a new C16 tune as well as a 93 octane tune. I had mentioned to him the lower pulley avalable for the GT but I wanted to find out how much of a PITA it was to install which is why I wanted to know if anyone out in the GT circles had done one.
You can never have too much input!! I knew the 2.8 upper was fine with pump gas, but I wanted to make sure the 2.7 was the same before I ordered it.
Thanks again! Your input is greatly appreciated.
- Dec 21, 2009
- 83
He could have. I did not ask him. You guys are extremely quick with responses so I figured I would just post it. I just told him I would pick one up. I did not know they made a 2.8 and a 2.7.
Silverbullitt
GT Owner
How could the lower pulley be lighter? You need a larger lower pulley to create more boost. If it is larger than stock and lighter than stock is it as strong as stock????
- Dec 21, 2009
- 83
Its bigger, but its billet aluminum. Saves you about 10lbs of rotating mass. Really nice piece. I put one on my wifes mustang and could really notice the throttle response improvement. If it was not such a pain to install on the GT I would try one.
Extreme281
Extreme281
- Aug 23, 2009
- 47
The IW west balancer is a very nice piece and removing 10lbs from the snout of any crank will help in power especially when it drives a blower ,im considering installing one i will let you know if its very difficult,this is a balancer of a GT40 which looks like the 07 GT500 balancer which is really crap and Ford even changed it on the 08 GT500,if i was you i would run the upper/lower combo .Do it right the first time
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Extreme281
Extreme281
- Aug 23, 2009
- 47
Jon Lund i heard is a really good tuner ,did he tune ur car already with the 2.7 ? Ask him about doing the IW 10% under and the 2.7 upper with pump and VP 109,there is numerous amounts of GT500 people with this set-up and is proven to work and im sure it will do better and hold up in a GT40 5.4. I ran a VMP tune for Justin on my GT500 with 10% under and a 2.65 upper and made awesome gains.Maybe you can work out a custom tune with that set-up and i will help with the cost for a tune for mine ,let me know
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MAD IN NC
Proud Owner/ BOD blah bla
It's like Herpes!
This item of IW has been brought up many times....
Suggest ALL look at this thread. Indy and Shadowman made their call......
http://www.fordgtforum.com/forums/showthread.php?p=110748&highlight=Balancer#post110748
It was left with Bony CLOSING THE THREAD... how many times did he do that - not many....
This item of IW has been brought up many times....
Suggest ALL look at this thread. Indy and Shadowman made their call......
http://www.fordgtforum.com/forums/showthread.php?p=110748&highlight=Balancer#post110748
It was left with Bony CLOSING THE THREAD... how many times did he do that - not many....
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Extreme281
Extreme281
- Aug 23, 2009
- 47
I just see a long discusion on everybody theory about the balancer .I never asked if it works .I will install the IW 10% since nobody ever did and remove the balancer Ford recalled on the 07 Gt500 which the GT has .If your not about making the most power then the balancer is not for you
zrchris
GT Owner
This lower pulley business I know nothing about, but the upper pulley I have been considering. It turns out there are many sizes out there. The biggest question is how much boost can you put out before the belt slips? I recall someone claiming there was a limit, even with pulley spacers or proper belt length. (The Whipple SC of course has a far better drive arrangement than stock.)
As far pulley choices for the stock SC, here is what I have found and some projections I estimated (email me if you want the spreadsheet){edit: updated w/ polynomial fit to more accurately match tuner data}:
brand dia psi rwhp +hp
stock 3.307 12.50 535.0 0.0
Roush 3.150 13.13 559.9 24.9
Metco 3.000 13.78 585.5 50.5
FRPP 2.884 14.33 606.4 71.4
Whipple 2.870 14.40 609.0 74.0
Metco 2.800 14.76 622.3 87.3
Hefner 2.750 15.03 632.0 97.0
Whipple 2.700 15.31 641.8 106.8
I have not included the Kenne Bell setup (2.75 same as Hefner), and Hefner's pulley could very well be the same size as Whipple in reality (good chance they are the same part). Yeah I believe even 2.7 is safe with 93 octane with the right tune (keep your life simple, see Torie as I will soon). Seeing this it's easy to get greedy. But I'm more concerned about why FRPP didn't go smaller- maybe for concerns of engine or belt life? Maybe to stay under 15 psi max?
As far pulley choices for the stock SC, here is what I have found and some projections I estimated (email me if you want the spreadsheet){edit: updated w/ polynomial fit to more accurately match tuner data}:
brand dia psi rwhp +hp
stock 3.307 12.50 535.0 0.0
Roush 3.150 13.13 559.9 24.9
Metco 3.000 13.78 585.5 50.5
FRPP 2.884 14.33 606.4 71.4
Whipple 2.870 14.40 609.0 74.0
Metco 2.800 14.76 622.3 87.3
Hefner 2.750 15.03 632.0 97.0
Whipple 2.700 15.31 641.8 106.8
I have not included the Kenne Bell setup (2.75 same as Hefner), and Hefner's pulley could very well be the same size as Whipple in reality (good chance they are the same part). Yeah I believe even 2.7 is safe with 93 octane with the right tune (keep your life simple, see Torie as I will soon). Seeing this it's easy to get greedy. But I'm more concerned about why FRPP didn't go smaller- maybe for concerns of engine or belt life? Maybe to stay under 15 psi max?
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BlackICE
GT Owner
Note that available serpentine belt lengths should be should also be a consideration when changing drive, or supercharger pulley sizes. Not too many sizes are a stocked item.
Great post. thank you.
How did you compile the complete stats?
642 RWHP with a Whipple 2.7" pulley on a stock SC is really incredible.
Can someone please validate this with real hard dyno data?
This would be great.
Crankshaft harmonic damper.
Chip - I will take the liberty of re-quoting Bony two years ago when he was re-quoting Indy GT.
Bony - I will take the liberty of reposting Indy GT's comments:-
Guys, this is an interesting post. Unfortunately quite a bit of mis-information is posted herein. I have done some research on this topic so let me try to clarify some of the points brought up to help un-confuse:
1) The crankshaft assembly we have in our GT’s is just fine for its intended design condition. 550 hp was the engine power design point at 6500 rpm redline and as Dave correctly points out many owners have moded-up to 800-900 hp and have had no reported crankshaft issues. Will you have torsional issues if you push the engine (by whatever mod you care to apply) to 1300 hp (235% of design power) and turn the engine 7500 rpm (+15% overspeed) my guess would be yes! But the engine was not DESIGNED to run at that power reliably. So if one owner chooses to run to those outlying conditions and has a problem, why is the “sky falling” for the 99.999% of us other owners? Clearly it is not.
2) The crankshaft harmonic damper selected by the Ford design engineers for the GT engine is a “viscous” damped balancer. This is a sophisticated (and expensive) damper which uses a precisely tuned weight which moves within the damper annulus to attenuate crankshaft harmonics. The annulus is filled with a (relatively temperature insensitive) viscous silicon fluid. During engine development the team spent many hours of dyno testing to determine the various “harmonics” (dynamic resonances at power of the rotating crankshaft assembly with the rods, bearings, pistons, rings and flywheel) of our GT engine crankshaft. Typically the 4th order harmonic of the engine firing order, is the most dominant mode and the OEM damper effectively dissipates this mode. I would think it reasonable that the telemetry and measuring equipment necessary to map these harmonic modes up to the 12th harmonic would be beyond most if not all aftermarket balancer companies resourses. Thus I would conclude the Ford engine team knows more about our engine dynamics than most others and if a 20 pound damper was specified, then that is what the engine needs.
3) Engine torsional and bending harmonics are difficult to understand even for most engineers. Comments such as reduced rotating mass is always a gain and thus leads to less stress on the crank are not always true. Crankshaft harmonics are not “intuitive” and often counter to what you might think is the correct answer. Thus a 10 pound damper is not ALWAYS better than a 20 pound damper just because it is 10 pounds lighter. It depends on what mass is necessary to attenuate the quantified responses. Will the engine acceleration characteristics be faster with a 10# damper vs. a 20# damper? Possibly. But in my opinion given the torque output of our blown engine and the mass of the rotating components the engine must accelerate to move the car (i.e. clutch, transaxle gears, differential, rear axles, wheels and tires) the 10# delta in damper weight could likely not be felt by the driver.
4) The viscous damper also has the attribute of providing damping over a broad range of engine rpm. The other type damper is termed “elastomeric” as it uses a compliant rubber layer between the damper hub and harmonic tuning mass. This type of damper is less expensive, narrower in its attenuation properties and not as effective as the vicious style at high rpm. Ford has opted to use a “dual-mode elastomeric” harmonic balancer for the 2008 GT500 MOD5.4 engine. Note this IS a different damper than the viscous damper used on all GT engines and is tuned to slightly different discrete frequencies. The GT500 crankshaft is slightly different than that used in the GT and thus the harmonic balancer is tuned as best the dual-mode elastomeric damper can do, for that specific engine. I would see little advantage of swapping the GT500 damper for the viscous GT damper to save the reported weight difference only to have a less effective damping system.
5) One must also consider the environment in which the component is expected to operate. Our mid-engine GT sees little if any airflow around the engine. Certainly the airflow cooling characteristics of a MOD5.4 engine in a front mounted GT500 are dissimilar to that of our GT engine. All harmonic dampers absorb and dissipate torsional vibrations. They attenuate the detrimental harmonics by converting the unwanted oscillations into heat energy. The elastomeric damper is more temperature sensitive and needs cooling air to dissipate this generated heat. Thus an application in a front engine car with cooling air bathing the engine is fine for this type of system, but not so good for a GT application which has little airflow to dissipate the converted heat energy. The viscious damper as OEM supplied is the better application here.
6) At the engine rpm ranges ALL of us owners will ever use there is NO risk of the OEM harmonic damper bursting. Certification testing of the GT balancer was made to 10,000 rpm and held for 2 minutes. The GT viscous damper is just fine for all engine speeds up to at least 7,000 rpm. The damper selected for the GT500 MOD5.4 which IS different than the GT damper was proof tested to 12,000 rpm. Thus there is no need to worry about a damper burst. Claims to the contrary are just not accurate.
7) There have been statements to the effect that the harmonic balancer is somehow connected to the rpm limitation (red line) placed on the engine. Again factually inaccurate. The redline speed of the engine is determined by engineering based on the calculated drivetrain stresses (piston pin, connecting rod, crankshaft throw fillets, main bearing caps, etc.), bearing oil film performance, valvetrain stresses/dynamics and desired engine longevity. Will the engine turn faster than 6500 rpm and not fail? Absolutely! Many of the tuners bump up the electronic redline as part of the tune. Will the engine still have the durability aspects the 300 hour Certification run at the OEM recognized redline? Likely not, but that’s what we owners trade off for the increased rpm capability. And we are not likely to use all the engine longevity Ford built into the engine anyway with our limited driving use.
Sorry if this was long winded, but there appeared to be many different aspects to cover. To summarize, the viscous damper Ford supplied on the GT engine is just fine at attenuating the engine crankshaft harmonics throughout the rpm range most of us owners will ever use. Hope this helps others understand some of the complexities of this damper.
Chip - I will take the liberty of re-quoting Bony two years ago when he was re-quoting Indy GT.
Bony - I will take the liberty of reposting Indy GT's comments:-
Guys, this is an interesting post. Unfortunately quite a bit of mis-information is posted herein. I have done some research on this topic so let me try to clarify some of the points brought up to help un-confuse:
1) The crankshaft assembly we have in our GT’s is just fine for its intended design condition. 550 hp was the engine power design point at 6500 rpm redline and as Dave correctly points out many owners have moded-up to 800-900 hp and have had no reported crankshaft issues. Will you have torsional issues if you push the engine (by whatever mod you care to apply) to 1300 hp (235% of design power) and turn the engine 7500 rpm (+15% overspeed) my guess would be yes! But the engine was not DESIGNED to run at that power reliably. So if one owner chooses to run to those outlying conditions and has a problem, why is the “sky falling” for the 99.999% of us other owners? Clearly it is not.
2) The crankshaft harmonic damper selected by the Ford design engineers for the GT engine is a “viscous” damped balancer. This is a sophisticated (and expensive) damper which uses a precisely tuned weight which moves within the damper annulus to attenuate crankshaft harmonics. The annulus is filled with a (relatively temperature insensitive) viscous silicon fluid. During engine development the team spent many hours of dyno testing to determine the various “harmonics” (dynamic resonances at power of the rotating crankshaft assembly with the rods, bearings, pistons, rings and flywheel) of our GT engine crankshaft. Typically the 4th order harmonic of the engine firing order, is the most dominant mode and the OEM damper effectively dissipates this mode. I would think it reasonable that the telemetry and measuring equipment necessary to map these harmonic modes up to the 12th harmonic would be beyond most if not all aftermarket balancer companies resourses. Thus I would conclude the Ford engine team knows more about our engine dynamics than most others and if a 20 pound damper was specified, then that is what the engine needs.
3) Engine torsional and bending harmonics are difficult to understand even for most engineers. Comments such as reduced rotating mass is always a gain and thus leads to less stress on the crank are not always true. Crankshaft harmonics are not “intuitive” and often counter to what you might think is the correct answer. Thus a 10 pound damper is not ALWAYS better than a 20 pound damper just because it is 10 pounds lighter. It depends on what mass is necessary to attenuate the quantified responses. Will the engine acceleration characteristics be faster with a 10# damper vs. a 20# damper? Possibly. But in my opinion given the torque output of our blown engine and the mass of the rotating components the engine must accelerate to move the car (i.e. clutch, transaxle gears, differential, rear axles, wheels and tires) the 10# delta in damper weight could likely not be felt by the driver.
4) The viscous damper also has the attribute of providing damping over a broad range of engine rpm. The other type damper is termed “elastomeric” as it uses a compliant rubber layer between the damper hub and harmonic tuning mass. This type of damper is less expensive, narrower in its attenuation properties and not as effective as the vicious style at high rpm. Ford has opted to use a “dual-mode elastomeric” harmonic balancer for the 2008 GT500 MOD5.4 engine. Note this IS a different damper than the viscous damper used on all GT engines and is tuned to slightly different discrete frequencies. The GT500 crankshaft is slightly different than that used in the GT and thus the harmonic balancer is tuned as best the dual-mode elastomeric damper can do, for that specific engine. I would see little advantage of swapping the GT500 damper for the viscous GT damper to save the reported weight difference only to have a less effective damping system.
5) One must also consider the environment in which the component is expected to operate. Our mid-engine GT sees little if any airflow around the engine. Certainly the airflow cooling characteristics of a MOD5.4 engine in a front mounted GT500 are dissimilar to that of our GT engine. All harmonic dampers absorb and dissipate torsional vibrations. They attenuate the detrimental harmonics by converting the unwanted oscillations into heat energy. The elastomeric damper is more temperature sensitive and needs cooling air to dissipate this generated heat. Thus an application in a front engine car with cooling air bathing the engine is fine for this type of system, but not so good for a GT application which has little airflow to dissipate the converted heat energy. The viscious damper as OEM supplied is the better application here.
6) At the engine rpm ranges ALL of us owners will ever use there is NO risk of the OEM harmonic damper bursting. Certification testing of the GT balancer was made to 10,000 rpm and held for 2 minutes. The GT viscous damper is just fine for all engine speeds up to at least 7,000 rpm. The damper selected for the GT500 MOD5.4 which IS different than the GT damper was proof tested to 12,000 rpm. Thus there is no need to worry about a damper burst. Claims to the contrary are just not accurate.
7) There have been statements to the effect that the harmonic balancer is somehow connected to the rpm limitation (red line) placed on the engine. Again factually inaccurate. The redline speed of the engine is determined by engineering based on the calculated drivetrain stresses (piston pin, connecting rod, crankshaft throw fillets, main bearing caps, etc.), bearing oil film performance, valvetrain stresses/dynamics and desired engine longevity. Will the engine turn faster than 6500 rpm and not fail? Absolutely! Many of the tuners bump up the electronic redline as part of the tune. Will the engine still have the durability aspects the 300 hour Certification run at the OEM recognized redline? Likely not, but that’s what we owners trade off for the increased rpm capability. And we are not likely to use all the engine longevity Ford built into the engine anyway with our limited driving use.
Sorry if this was long winded, but there appeared to be many different aspects to cover. To summarize, the viscous damper Ford supplied on the GT engine is just fine at attenuating the engine crankshaft harmonics throughout the rpm range most of us owners will ever use. Hope this helps others understand some of the complexities of this damper.
Well stated, Chip.
I have used "Fluidamper"s on my boat's big block Chevy engines for precisely the same reason, as they dissipate harmonics over a wide range of frequencies, as opposed to an elastomeric damper which is designed to eliminate only the worst harmonics. Elastomeric dampers are less expensive to manufacture, and are a good choice for high volume production engines. For the GT, a limited production item, the choice of a more expensive fluid damper gives us greater protection from harmonics of many frequencies as well as the base frequencies.
I have used "Fluidamper"s on my boat's big block Chevy engines for precisely the same reason, as they dissipate harmonics over a wide range of frequencies, as opposed to an elastomeric damper which is designed to eliminate only the worst harmonics. Elastomeric dampers are less expensive to manufacture, and are a good choice for high volume production engines. For the GT, a limited production item, the choice of a more expensive fluid damper gives us greater protection from harmonics of many frequencies as well as the base frequencies.