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CR MAD MAX BUGGY Samba Member
Joined: October 19, 2019 Posts: 64 Location: Costa Rica
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Posted: Fri Jul 30, 2021 6:31 pm Post subject: Torque VS. HorsePower |
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Ok so, I have a question here.
Knowing that torque is the force of an engine (basically) and horse power is how fast that force is delivered…. What do we get when we increase the size of our engine? Do we get an increment of both values or only torque or only horsepower?
What if I don't make my engine bigger but I put a bigger camshaft? Do we get only power or we get both?
Im asking this question because I am upgrading my engine from a mild 2021cc with a C35 cam to a 2442cc with a 86B cam. Heads and carbs and all that are proportionally equal to each engine so lets don't get into those subjects nut speaking about engine size and camshafts, I would like to know what impact the most on torque and horsepower and what Should I spect from this upgrade.
It will be used on a Meyers Manx street buggy.
Thank you all! |
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Dan Ruddock Samba Member
Joined: October 25, 2012 Posts: 3574 Location: Sarasota, in my adopted state of Florida
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Posted: Sat Jul 31, 2021 5:09 am Post subject: Re: Torque VS. HorsePower |
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As you increase displacement with all else the same as the smaller engine you will get both a torque and HP increase but both will peak at a lower RPM.
To maintain the same RPM powerband as the smaller engine you must add more cam and better breathing which will add more HP with close to the same torque which will peak at a higher RPM.
Adding more usable RPM to a fixed displacement will add HP but will move the torque peak to a higher RPM and reduce low RPM torque.
Torque is a function of displacement and HP is a function of RPM.
The last of the NA formula 1 engines made their peak HP/RPM in the high teens. Amazing engines.
Hope this helps. Dan |
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Vanapplebomb Samba Member
Joined: November 03, 2010 Posts: 5389 Location: Holland, MI
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Posted: Sat Jul 31, 2021 6:38 am Post subject: Re: Torque VS. HorsePower |
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HP = Torque * RPM / 5252
Increasing either Torque or RPM will yield more HP, both of which an upgraded cam can do.
Torque is largely a function of displacement and efficiency, so larger engines tend to make more power for a given speed relative to a smaller one. _________________ 1800 Type 4 Berrien 295
http://www.thesamba.com/vw/forum/viewtopic.php?t=487021 |
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CR MAD MAX BUGGY Samba Member
Joined: October 19, 2019 Posts: 64 Location: Costa Rica
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Posted: Sat Jul 31, 2021 7:07 am Post subject: Re: Torque VS. HorsePower |
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Thanks for the comments.
Yeah it all makes sense, as you guys are saying both measures will be achieved by both modifications independently.
Looks like I will get what Im looking for with this engine upgrade.
Let be show the upgrade in a more detail way.
Actual engine:
2021cc (76X92)
Scat C35 camshaft straigh cut gears
CB Performance Panchito heads 40X35
VW I Beams
Wiseco pistons
CB Crankshaft
9,5:1 CR
Dual 44 IDF Webers with the upgrade kit and Jet Doctor from CB Performance.
This engine made 95 Wheel Horsepower and 100 FT/lbs Torque at 5500 rpm.
Engine Upgrade
2442cc (88X94)
Webcam 86B straight cut gears
EMPI Wedge Port Heads 44X37,5
CB Performance H Beams
Sleeper skirt pistons
Scat Pro Billet Flange Crankshaft. The one that has holes all around and uses screws.
10,5:1 CR
Dual 44 IDF Webers with the upgrade kit and Jet Doctor from CB Performance.
I am trying to achieve at least 150 Wheel horsepower with this setup.
I would have liked to used the 86C Camshaft or the SLR EXR 318 Camshaft to get more higher end power as the torque will be deliverde by the engine size.
This is for my Street buggy that weights about 1300 / 1400 pounds.
The engine is allready built so no oportunity to change anything apart from the carbs later some time.
Let me know what you guys think. |
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Dan Ruddock Samba Member
Joined: October 25, 2012 Posts: 3574 Location: Sarasota, in my adopted state of Florida
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Posted: Sat Jul 31, 2021 7:19 am Post subject: Re: Torque VS. HorsePower |
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Hope the crank has T4 mains. Not a fan of empi heads. |
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CR MAD MAX BUGGY Samba Member
Joined: October 19, 2019 Posts: 64 Location: Costa Rica
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Posted: Sat Jul 31, 2021 7:31 am Post subject: Re: Torque VS. HorsePower |
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Dan Ruddock wrote: |
Hope the crank has T4 mains. Not a fan of empi heads. |
Second person I hear not being fan of EMPI heads.
What is not to like about them or what has been your experience?
We had that option or a set of BugPack super flows but I prefered the EMPI heads for the street. |
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67rustavenger Samba Member
Joined: February 24, 2015 Posts: 9663 Location: Oregon
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Posted: Sat Jul 31, 2021 8:07 am Post subject: Re: Torque VS. HorsePower |
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Dub-Dyno indicates,
151.8 HP @6000 RPM
156.3 FP Torque @ 4500 RPM
The above is using 1.4:1 rockers and 1 7/8 Exhaust.
This is just an estimate of the potential for your proposed build. _________________ I have learned over the years.
Cheap parts are gonna disappoint you.
Buy Once, Cry Once!
There's never enough time to do it right the first time. But there's always enough time to do it thrice.
GFY's Xevin and VW_Jimbo! |
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txoval Samba Member
Joined: January 23, 2004 Posts: 3540 Location: The Woodlands, TX
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Posted: Sat Jul 31, 2021 8:10 am Post subject: Re: Torque VS. HorsePower |
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Is the Dub Dyno flywheel or wheel HP?
If you only get 150hp at the flywheel with a 2400cc engine something is wrong. |
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67rustavenger Samba Member
Joined: February 24, 2015 Posts: 9663 Location: Oregon
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Posted: Sat Jul 31, 2021 8:14 am Post subject: Re: Torque VS. HorsePower |
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txoval wrote: |
Is the Dub Dyno flywheel or wheel HP?
If you only get 150hp at the flywheel with a 2400cc engine something is wrong. |
It doesn't indicate if it's wheel or flywheel. It's just an estimating tool to get you an idea of the build potential.
The limiting factor on the above proposed build are the Carbs and compression ratio. An 86b likes 9.5:1 CR. _________________ I have learned over the years.
Cheap parts are gonna disappoint you.
Buy Once, Cry Once!
There's never enough time to do it right the first time. But there's always enough time to do it thrice.
GFY's Xevin and VW_Jimbo! |
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67rustavenger Samba Member
Joined: February 24, 2015 Posts: 9663 Location: Oregon
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Posted: Sat Jul 31, 2021 8:22 am Post subject: Re: Torque VS. HorsePower |
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For laughs,
I ran the numbers using, L7 44x37.5 heads, 86c cam at 10.5:1 CR, 48 IDA's.
197.0 HP @ 7500 RPM.
161.6 FP Torque @ 5500 RPM.
Much better! _________________ I have learned over the years.
Cheap parts are gonna disappoint you.
Buy Once, Cry Once!
There's never enough time to do it right the first time. But there's always enough time to do it thrice.
GFY's Xevin and VW_Jimbo! |
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CR MAD MAX BUGGY Samba Member
Joined: October 19, 2019 Posts: 64 Location: Costa Rica
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Posted: Sat Jul 31, 2021 8:46 am Post subject: Re: Torque VS. HorsePower |
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67rustavenger wrote: |
For laughs,
I ran the numbers using, L7 44x37.5 heads, 86c cam at 10.5:1 CR, 48 IDA's.
197.0 HP @ 7500 RPM.
161.6 FP Torque @ 5500 RPM.
Much better! |
Thanks a lot for the information.
I must correct something from my above post.
The 2442cc engine has a 10:1 CR and not a 10,5:1 like I said. My bad. That must benefit more the 86B cam used.
The carbs will definately be upgraded some time to 48IDAs for sure but I will star with the 44 IDF I already have.
The Empi heads, they are supposed to be GTV-2 L7 heads 44X37,5.
I agree the best cam for this setup should have been the 86C which will be upgraded later on when the engine gets to need a refresh. |
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67rustavenger Samba Member
Joined: February 24, 2015 Posts: 9663 Location: Oregon
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Posted: Sat Jul 31, 2021 8:53 am Post subject: Re: Torque VS. HorsePower |
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CR MAD MAX BUGGY wrote: |
67rustavenger wrote: |
For laughs,
I ran the numbers using, L7 44x37.5 heads, 86c cam at 10.5:1 CR, 48 IDA's.
197.0 HP @ 7500 RPM.
161.6 FP Torque @ 5500 RPM.
Much better! |
Thanks a lot for the information.
I must correct something from my above post.
The 2442cc engine has a 10:1 CR and not a 10,5:1 like I said. My bad. That must benefit more the 86B cam used.
The carbs will definately be upgraded some time to 48IDAs for sure but I will star with the 44 IDF I already have.
The Empi heads, they are supposed to be GTV-2 L7 heads 44X37,5.
I agree the best cam for this setup should have been the 86C which will be upgraded later on when the engine gets to need a refresh. |
10.0:1 CR will get ya,
155.1 HP
148.6 FP Torque.
Using 44 IDF's
What exhaust size do you intend to run? _________________ I have learned over the years.
Cheap parts are gonna disappoint you.
Buy Once, Cry Once!
There's never enough time to do it right the first time. But there's always enough time to do it thrice.
GFY's Xevin and VW_Jimbo! |
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Back to top |
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CR MAD MAX BUGGY Samba Member
Joined: October 19, 2019 Posts: 64 Location: Costa Rica
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Posted: Sat Jul 31, 2021 9:01 am Post subject: Re: Torque VS. HorsePower |
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67rustavenger wrote: |
CR MAD MAX BUGGY wrote: |
67rustavenger wrote: |
For laughs,
I ran the numbers using, L7 44x37.5 heads, 86c cam at 10.5:1 CR, 48 IDA's.
197.0 HP @ 7500 RPM.
161.6 FP Torque @ 5500 RPM.
Much better! |
Thanks a lot for the information.
I must correct something from my above post.
The 2442cc engine has a 10:1 CR and not a 10,5:1 like I said. My bad. That must benefit more the 86B cam used.
The carbs will definately be upgraded some time to 48IDAs for sure but I will star with the 44 IDF I already have.
The Empi heads, they are supposed to be GTV-2 L7 heads 44X37,5.
I agree the best cam for this setup should have been the 86C which will be upgraded later on when the engine gets to need a refresh. |
10.0:1 CR will get ya,
155.1 HP
148.6 FP Torque.
Using 44 IDF's
What exhaust size do you intend to run? |
I have the Meyers Manx 1 5/8” Exhaust with an A1 Race Bullet Muffler. |
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UK Luke 72 Samba Member
Joined: September 07, 2011 Posts: 2867 Location: Little Britain
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Alstrup Samba Member
Joined: July 12, 2007 Posts: 7181 Location: Videbaek Denmark
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Posted: Sat Jul 31, 2021 4:16 pm Post subject: Re: Torque VS. HorsePower |
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CR MAD MAX BUGGY wrote: |
67rustavenger wrote: |
For laughs,
I ran the numbers using, L7 44x37.5 heads, 86c cam at 10.5:1 CR, 48 IDA's.
197.0 HP @ 7500 RPM.
161.6 FP Torque @ 5500 RPM.
Much better! |
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Which it will never make. Not even close.
Remember, the Empi GTV series heads are really just DRD heads, with a port and seat job that was modern 30 years ago or something like that. In my time I have had several engines on the dyno which had L5/6 & 7 heads installed. They all lacked both power and torque, usually in the window of 10-20 hp less than "promised or expected!" Even L3´s. (NOT to be confused with the L3 heads sold through Aircooled.net. They are different. I guess he just kept the name for the ease of it) I have corrected about 10 set of these L heads and I have always been able to recover at least 10 hp and most of the time upwards of 17-20 hp and on one sgl occasion 26 hp (that was along with a cam swop, so not totally comparable, but it was still from 178 to 204 hp and from 210 to over 260 Nm torque) and I am still on the apprentice stage when it comes to porting.
I know you will ask next, what is wrong with them. Everything from 1" above the seat to ˝" below the seat.
Best all round high power CNC heads on the market is CB hands down. Go into hand ported heads and there are several really good suppliers. Just chose the heads that are in the performance window you really want, not what could be fun. That typically ends up being a disappointment unless its a weekend warrior type of vehichle. _________________ https://www.thesamba.com/vw/forum/viewtopic.php?t=435993 |
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CR MAD MAX BUGGY Samba Member
Joined: October 19, 2019 Posts: 64 Location: Costa Rica
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Posted: Sat Jul 31, 2021 9:03 pm Post subject: Re: Torque VS. HorsePower |
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Alstrup wrote: |
CR MAD MAX BUGGY wrote: |
67rustavenger wrote: |
For laughs,
I ran the numbers using, L7 44x37.5 heads, 86c cam at 10.5:1 CR, 48 IDA's.
197.0 HP @ 7500 RPM.
161.6 FP Torque @ 5500 RPM.
Much better! |
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Which it will never make. Not even close.
Remember, the Empi GTV series heads are really just DRD heads, with a port and seat job that was modern 30 years ago or something like that. In my time I have had several engines on the dyno which had L5/6 & 7 heads installed. They all lacked both power and torque, usually in the window of 10-20 hp less than "promised or expected!" Even L3´s. (NOT to be confused with the L3 heads sold through Aircooled.net. They are different. I guess he just kept the name for the ease of it) I have corrected about 10 set of these L heads and I have always been able to recover at least 10 hp and most of the time upwards of 17-20 hp and on one sgl occasion 26 hp (that was along with a cam swop, so not totally comparable, but it was still from 178 to 204 hp and from 210 to over 260 Nm torque) and I am still on the apprentice stage when it comes to porting.
I know you will ask next, what is wrong with them. Everything from 1" above the seat to ˝" below the seat.
Best all round high power CNC heads on the market is CB hands down. Go into hand ported heads and there are several really good suppliers. Just chose the heads that are in the performance window you really want, not what could be fun. That typically ends up being a disappointment unless its a weekend warrior type of vehichle. |
Yes I would like to put an 86C or an EXR 318 camshaft later on with a set of 48IDAs and maybe the CB street fighter heads or the wedge port… |
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CR MAD MAX BUGGY Samba Member
Joined: October 19, 2019 Posts: 64 Location: Costa Rica
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Posted: Sat Jul 31, 2021 9:30 pm Post subject: Re: Torque VS. HorsePower |
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This are the heads that the engine has right now.
Supposted to be GTV-2 L7 but cant asure that.
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FreeBug Samba Member
Joined: March 12, 2012 Posts: 4278 Location: deepest, darkest Switzerland
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Posted: Sun Aug 01, 2021 1:53 am Post subject: Re: Torque VS. HorsePower |
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Holy crap, that engine case is beautiful! |
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Alstrup Samba Member
Joined: July 12, 2007 Posts: 7181 Location: Videbaek Denmark
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CR MAD MAX BUGGY Samba Member
Joined: October 19, 2019 Posts: 64 Location: Costa Rica
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Posted: Sun Aug 01, 2021 9:23 am Post subject: Re: Torque VS. HorsePower |
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Alstrup wrote: |
Those ports look to be hand ported or smoothed out after cnc. |
I have no idea. They are supposed to b like that from factory. Like I said they are new EMPI GTV-2 Heads. They should do the job for now. |
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