Cup electric PS pump conversion
#46
Rennlist Member
Originally Posted by powdrhound
I'm trying to decide on which fitting to get. Looking at the comparison of the fittings you posted above, it looks like the OEM and Rebel are identical while the HRG is slightly different by a few hundreds. Not sure if that matters. Has anyone installed and verified fitment of both the Rebel and the HRG? I don't want any surprises. Anyone have links or part numbers for for both the Rebel or HRG?
Thanks...
Thanks...
#47
Couple of questions. I am installing this in my boxster racecar.
1. BMWTYE, where did you get the mounting bracket from?
2. Mine came with the motorsports lines, but they are a PITA with the other stuff I already have in the frunk. Using the HRG/ Rebel racing fittings, did you just use standard AN lines to make the lines, or are special high pressure lines needed?
3. Any special fluid needed? Or just using the standard Pentosin stuff?
4. Does it have to rubber mounted or can it be hard mounted like the one with the band clamp showed?
Thanks
Brandon
1. BMWTYE, where did you get the mounting bracket from?
2. Mine came with the motorsports lines, but they are a PITA with the other stuff I already have in the frunk. Using the HRG/ Rebel racing fittings, did you just use standard AN lines to make the lines, or are special high pressure lines needed?
3. Any special fluid needed? Or just using the standard Pentosin stuff?
4. Does it have to rubber mounted or can it be hard mounted like the one with the band clamp showed?
Thanks
Brandon
#48
I'm curious why people are making this modification from a mechanically driven to electric power steering pump. Does it save any weight, consume less power, or change the weight distribution in any significant way? Or is it more the "cool factor" that drives this?
One post mentioned that it eliminates a Pentosin fire hazard at the rear. But the fire hazard of engine oil, coolant, and gasoline is still there. And then it moves the fire hazard to the front, where there's already gasoline and brake fluid that can burn, and it adds an electrical connection which carries a small risk too. I can see that it eliminates the need to undo a hydraulic line during an engine drop, but how often do you really do an engine drop? And undoing that line during an engine drop only takes just seconds if you know what you're doing. My guess is that the weight is similar either way and that the power draw is similar too, whether it be through the mechanical pump or through the alternator. And by moving it to the front, you eliminate some trunk space, which wouldn't be ideal for a street car. I don't know the reasons the factory did it for their race cars, but my guess it was mostly for simplicity. But if you already have a working system built in to your street car, is it worth this change from any measurable mechanical standpoint? It's fine if the only reason is "that it's cool." Lots of changes are made for that reason, and that's legitimate as far as I'm concerned. But let's call it what it is...
One post mentioned that it eliminates a Pentosin fire hazard at the rear. But the fire hazard of engine oil, coolant, and gasoline is still there. And then it moves the fire hazard to the front, where there's already gasoline and brake fluid that can burn, and it adds an electrical connection which carries a small risk too. I can see that it eliminates the need to undo a hydraulic line during an engine drop, but how often do you really do an engine drop? And undoing that line during an engine drop only takes just seconds if you know what you're doing. My guess is that the weight is similar either way and that the power draw is similar too, whether it be through the mechanical pump or through the alternator. And by moving it to the front, you eliminate some trunk space, which wouldn't be ideal for a street car. I don't know the reasons the factory did it for their race cars, but my guess it was mostly for simplicity. But if you already have a working system built in to your street car, is it worth this change from any measurable mechanical standpoint? It's fine if the only reason is "that it's cool." Lots of changes are made for that reason, and that's legitimate as far as I'm concerned. But let's call it what it is...
Last edited by Rob S; 05-21-2018 at 01:15 PM.
#49
I'm curious why people are making this modification from a mechanically driven to electric power steering pump. Does it save any weight, consume less power, or change the weight distribution in any significant way? Or is it more the "cool factor" that drives this?
One post mentioned that it eliminates a Pentosin fire hazard at the rear. But the fire hazard of engine oil, coolant, and gasoline is still there. And then it moves the fire hazard to the front, where there's already gasoline and brake fluid that can burn, and it adds an electrical connection which carries a small risk too. I can see that it eliminates the need to undo a hydraulic line during an engine drop, but how often do you really do an engine drop? And undoing that line during an engine drop only takes just seconds if you know what you're doing. My guess is that the weight is similar either way and that the power draw is similar too, whether it be through the mechanical pump or through the alternator. And by moving it to the front, you eliminate some trunk space, which wouldn't be ideal for a street car. I don't know the reasons the factory did it for their race cars, but my guess it was mostly for simplicity. But if you already have a working system built in to your street car, is it worth this change from any measurable mechanical standpoint? It's fine if the only reason is "that it's cool." Lots of changes are made for that reason, and that's legitimate as far as I'm concerned. But let's call it what it is...
One post mentioned that it eliminates a Pentosin fire hazard at the rear. But the fire hazard of engine oil, coolant, and gasoline is still there. And then it moves the fire hazard to the front, where there's already gasoline and brake fluid that can burn, and it adds an electrical connection which carries a small risk too. I can see that it eliminates the need to undo a hydraulic line during an engine drop, but how often do you really do an engine drop? And undoing that line during an engine drop only takes just seconds if you know what you're doing. My guess is that the weight is similar either way and that the power draw is similar too, whether it be through the mechanical pump or through the alternator. And by moving it to the front, you eliminate some trunk space, which wouldn't be ideal for a street car. I don't know the reasons the factory did it for their race cars, but my guess it was mostly for simplicity. But if you already have a working system built in to your street car, is it worth this change from any measurable mechanical standpoint? It's fine if the only reason is "that it's cool." Lots of changes are made for that reason, and that's legitimate as far as I'm concerned. But let's call it what it is...
#50
Drifting
Thread Starter
I think for a primarily street driven car there is no hugely beneficial reason...kind of like changing most things. For track duty it is a bit different. The overflow tank in the stock setup sits right above the engine and if you have a front wide end conversion it is very easy to overheat the OEM pump, which then sends the fluid flying into the engine bay (usually covering the air box). The electric unit can deal with the strain better, provides better weight balance being in the front and is easier to service or take out and replace being in the front. Also removing the additional pulley from the engine frees up some power as well. Again, all track considerations. Otherwise you are doing a lot of modification work that does not yield performance gains on the street, but may add to the coolness factor!
#51
To each his own, of course, but I think the real reason for doing this is to be able to say that you did! As for weight and distribution, the weight of the electric pump is likely equal to or greater than that of the hydraulic pump and drive system -- which is so small as to be equivalent to about a gallon of gasoline, so it's not likely to make any readable difference, even for hard-core track guys. And there's no free lunch as far as power consumption is concerned -- you have to drive a pump one way or the other, and it's usually more efficient to mechanically drive a pump than it is to use electrical energy from the alternator to drive a motorized pump. As for leaks in the engine compartment, that should never happen, but if there's even a chance of it, it would be easy to attach an overflow catch tank from the reservoir to capture any potential spillage, just as Porsche does on the electric pump in the trunk of the factory RSRs and Cup cars. And if failure of the mechanical pump is an issue, which is rare, it doesn't take all that long to drop the engine to fix it (if that's even necessary), and chances are that if you had to drop the engine, you'd be glad to have it out and do service work for other reasons as well. Besides, to make this conversion, it sounds like you'd be dropping the engine just to remove the mechanical pump anyway!
I agree that to go electric, the engine compartment would be one notch less cluttered, if that's important to you. But there's still a lot of mechanical clutter that you can't eliminate there, and by moving the pump forward, the trunk becomes one notch more cluttered in the process. It's a trade-off.
So, I'm not convinced that there's a good and legitimate performance, convenience, or safety reason to do this to a factory street car, even if it's used on the track. But hey, if you think it's cool, then go for it! I even have a pump to sell if someone's interested. This is a newly remanufactured VDO pump that is equivalent to those used in the earlier 996 Cup, R, and RS cars, and is a drop-in replacement for them. Obviously, to fit it to a street car would take some mounting hardware, plumbing, and electrical work. PMNA wanted about $1800 for the new version of the early Cup pump last I looked, which was 3 years ago. I'll sell for $600 plus shipping.
I agree that to go electric, the engine compartment would be one notch less cluttered, if that's important to you. But there's still a lot of mechanical clutter that you can't eliminate there, and by moving the pump forward, the trunk becomes one notch more cluttered in the process. It's a trade-off.
So, I'm not convinced that there's a good and legitimate performance, convenience, or safety reason to do this to a factory street car, even if it's used on the track. But hey, if you think it's cool, then go for it! I even have a pump to sell if someone's interested. This is a newly remanufactured VDO pump that is equivalent to those used in the earlier 996 Cup, R, and RS cars, and is a drop-in replacement for them. Obviously, to fit it to a street car would take some mounting hardware, plumbing, and electrical work. PMNA wanted about $1800 for the new version of the early Cup pump last I looked, which was 3 years ago. I'll sell for $600 plus shipping.
#52
It sounds like you asked a question that you are convinced you know the answer to
But seriously think of it this way:
Overall there is a clear reason as to why the race car comes with this setup, but you are absolutely right, that on a normal street drive GT3 the mod is pointless other for the "uniqueness" factor. I was just sharing the reasons I would have it in my street car that became the track car.
But seriously think of it this way:
- Weight - You are not saving weight, you are distributing it to the front, which is significant as these cars obviously have a rear weight bias. Every bit helps on a track car, otherwise why would light weight mods like battery, windows, etc. exist and be expensive? Less weight = speed.
- Safety - On a street driven car there are no leaks as the pump is not under stress. If you have a cup car conversion and are using wide front tires and go fast around the track it will definitely overheat and fail, so having the pump up front reduces the risk. Installing an overflow reservoir is a possibility, but now you have to find the space in the engine compartment.
- Convenience - Race teams run these pumps for 40 hours and replace them, because they fail due to stress. Having easy access to the pump and the steering system makes it easier and faster. You don't have to drop the engine to take out the original pump and can just drain and leave the plumbing in the car.
- Efficiency - The alternator already provides sufficient current to drive the pump. I am not sure that the engine has to work any harder to produce that energy.
Overall there is a clear reason as to why the race car comes with this setup, but you are absolutely right, that on a normal street drive GT3 the mod is pointless other for the "uniqueness" factor. I was just sharing the reasons I would have it in my street car that became the track car.
The following users liked this post:
frederickcook87 (06-12-2022)
#53
Rennlist Member
having just replaced the lines on my RS due to leaks at the hose connections leaks are not uncommon. I know of at least 4 other 997 generation cars with the same issue.
My pump is fine. Engine came out.
I kept stock setup. Just didn't want to mod my RS to that extent
Fire from pentosin is a very very real issue. .
On my 964 we ditched the PS system and put a cup pump on it. There is a definite weight savings and complication saving on these cars.
My pump is fine. Engine came out.
I kept stock setup. Just didn't want to mod my RS to that extent
Fire from pentosin is a very very real issue. .
On my 964 we ditched the PS system and put a cup pump on it. There is a definite weight savings and complication saving on these cars.
The following users liked this post:
frederickcook87 (06-12-2022)
#54
An electric pump has fewer losses. I.e. Electric motor can operate the pump at a fixed speed and will only draw as much current as is required, whereas an engine driven pump is always spun at (some ratio of) engine RPM. Any excess is then continually pumped through the bypass valve. So, a pump that can supply adequate fluid at 2k (engine) rpm is going to be pumping way more than is necessary at 8k rpm while also dealing with the mechanical losses from friction and inertia.
The following users liked this post:
frederickcook87 (06-12-2022)
#55
My local shop is using these 997Cup PS pump mounting brackets in their race cars and I bought one of these to use in my car. The bracket is pure jewelry as it's CNC machined from aluminum and consists of a base plate which the round body of the PS pump recesses into. The opening in the bracket use a dual rubber O-rings which snugly cradle the pump body isolating it from vibration transferring nto the bracket. The pump itself is supported via the 3 posts with rubber isolation mounts. Finally there are 4 short rubber "bumpers" that are bolted to the base of the bracket which will further provide NVH isolation (these are not visible in the pictures as they were not installed yet) from the chassis of the car. The whole assembly then bolts to the trunk floor. On my car which is a 996 chassis, this will bolt to the existing spare tire mount which is on all the 996 tubs even on the GT cars which do not use a spare tire. This can obviously bolt to anywhere one chooses but I found the spare tire mount on the front trunk floor to be a great location. My shop made up a hydraulic hose kit which will make this a plug and play set up. I am excited to finally get this in the car as it provides a super clean install.
Last edited by powdrhound; 06-21-2018 at 03:14 AM.
The following 2 users liked this post by powdrhound:
Darkstar1 (09-02-2023),
frederickcook87 (06-12-2022)
#57
Premium Sponsor
Rennlist
Site Sponsor
Rennlist
Site Sponsor
My local shop is using these 997Cup PS pump mounting brackets in their race cars and I bought one of these to use in my car. The bracket is pure jewelry as it's CNC machined from aluminum and consists of a base plate which the round body of the PS pump recesses into. The opening in the bracket use a dual rubber O-rings which snugly cradle the pump body isolating it from vibration transferring nto the bracket. The pump itself is supported via the 3 posts with rubber isolation mounts. Finally there are 4 short rubber "bumpers" that are bolted to the base of the bracket which will further provide NVH isolation (these are not visible in the pictures as they were not installed yet) from the chassis of the car. The whole assembly then bolts to the trunk floor. On my car which is a 996 chassis, this will bolt to the existing spare tire mount which is on all the 996 tubs even on the GT cars which do not use a spare tire. This can obviously bolt to anywhere one chooses but I found the spare tire mount on the front trunk floor to be a great location. My shop made up a hydraulic hose kit which will make this a plug and play set up. I am excited to finally get this in the car as it provides a super clean install.
__________________
PCA National Instructor
TPC Racing stats:
2023 Porsche Sprint Challenge 992 Cup Am Champion
2023 Porsche Sprint Challenge GT4 Pro-Am Team Champion
2022 Porsche Sprint Challenge 992 Cup & 991 Cup Champion
2020 IMSA GT3 Cup Challenge 2nd Championship
2018 IMSA GT3 Cup Challenge 2nd Championship
2016 IMSA GT3 Cup Challenge Champion
2013 IMSA GT3 Cup Challenge Champion
2006 Rolex-24 @ Daytona GT Champion
2004 Grand-Am SGS Class Champion
PCA National Instructor
TPC Racing stats:
2023 Porsche Sprint Challenge 992 Cup Am Champion
2023 Porsche Sprint Challenge GT4 Pro-Am Team Champion
2022 Porsche Sprint Challenge 992 Cup & 991 Cup Champion
2020 IMSA GT3 Cup Challenge 2nd Championship
2018 IMSA GT3 Cup Challenge 2nd Championship
2016 IMSA GT3 Cup Challenge Champion
2013 IMSA GT3 Cup Challenge Champion
2006 Rolex-24 @ Daytona GT Champion
2004 Grand-Am SGS Class Champion
#59
Drifting
Thread Starter