How much Gain with UDP & EWP
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From: Ramstein AB, Germany
How much Gain with UDP & EWP My friend has a 96 Impala SS with only 36,000 Miles. Only mod is a Borla Catback right now. The Opti went out & while we are replacing that I thought it would be a good idea to do the EWP & UDP with overdrive ALT pulley. What would this be worth? Around 10-15rwhp & tq sound about right? Also about how much will LT-1s gain with a set of Longtubes? Sorry for all the newb questions 
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From someone who actually has a fast b-body I would not recommend either on a mild street car. But I just know what I am talking about and actually put together a fast b-body.
The underdrive is not worth it because since the belt doesn't turn even the mechanical pump the potential gains are small. Removing the belt all together is only worth .1 at the track.
The electric pumps move LESS water at mid to high rpms and their failure mod is MUCH more dangerous than the mechanical.
The underdrive is not worth it because since the belt doesn't turn even the mechanical pump the potential gains are small. Removing the belt all together is only worth .1 at the track.
The electric pumps move LESS water at mid to high rpms and their failure mod is MUCH more dangerous than the mechanical.
From someone who actually has a fast b-body I would not recommend either on a mild street car. But I just know what I am talking about and actually put together a fast b-body.
The underdrive is not worth it because since the belt doesn't turn even the mechanical pump the potential gains are small. Removing the belt all together is only worth .1 at the track.
The electric pumps move LESS water at mid to high rpms and their failure mod is MUCH more dangerous than the mechanical.
The underdrive is not worth it because since the belt doesn't turn even the mechanical pump the potential gains are small. Removing the belt all together is only worth .1 at the track.
The electric pumps move LESS water at mid to high rpms and their failure mod is MUCH more dangerous than the mechanical.
10-15whp sounds possible. And I'd never spend money on the UDPs.
Underdrive pulleys with stock idle are likely to cause charging issues too.
A cam with raised idle and you wont see that negative but the only time I really see them being good is if the engine turns big rpms, enough to hurt accessories, or a road race car that overheats the PS system.
Yes folks do use electric pumps on daily drivers, and a FEW of them are man enough to admit it when the failure damages an engine. How many can't admit it?
A cam with raised idle and you wont see that negative but the only time I really see them being good is if the engine turns big rpms, enough to hurt accessories, or a road race car that overheats the PS system.
Yes folks do use electric pumps on daily drivers, and a FEW of them are man enough to admit it when the failure damages an engine. How many can't admit it?
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any water pump that fails and the subsequent result of excessive engine temps IF the operator fails to monitor their temp gage can occur.
the point being is the operator needs to monitor their gauges.
EWP can fail electrically and mechanically. The OEM pump can fail mechanically. Also both can leak enough to eventually effect engine temps.
Some get a EWP for more HP (motor does not drive it) where others, me, found them to be more reliable and stable that the OEM type.
I have had one on for 13 years and 85k miles. Coolant temps from the gauge under any condition I operate the car are the same.....YMMV
I take it the OP is asking the EWP? for more HP....it has been shown to improve that but IMHO I would spend $ on other mods to get HP. For me any HP advantage from a EWP was just a +.
the point being is the operator needs to monitor their gauges.
EWP can fail electrically and mechanically. The OEM pump can fail mechanically. Also both can leak enough to eventually effect engine temps.
Some get a EWP for more HP (motor does not drive it) where others, me, found them to be more reliable and stable that the OEM type.
I have had one on for 13 years and 85k miles. Coolant temps from the gauge under any condition I operate the car are the same.....YMMV
I take it the OP is asking the EWP? for more HP....it has been shown to improve that but IMHO I would spend $ on other mods to get HP. For me any HP advantage from a EWP was just a +.
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How does the engine not drive an electric waterpump?
The engine turns the alternator which runs all of the electricals.
They free up power by moving far less water.
Far as failure modes the electric is pretty likely to just stop working as it's failure mode, the mechanical is most likely to weep making the belt slip when you try and use the power steering, alerting you LONG before there is any risk of overheating.
The engine turns the alternator which runs all of the electricals.
They free up power by moving far less water.
Far as failure modes the electric is pretty likely to just stop working as it's failure mode, the mechanical is most likely to weep making the belt slip when you try and use the power steering, alerting you LONG before there is any risk of overheating.
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Using UDP's should be left to those not smart enough to make power in a more reliable way, I cant even grip the idea of installing them
As far as the ewp goes, I agree its not up to par at high rpm's, but I also know a TON of people are using them successfully daily driving.
As far as the ewp goes, I agree its not up to par at high rpm's, but I also know a TON of people are using them successfully daily driving.
You will fit in this board nicely.
I have the ASP underdrive balancer pulley which I purchased off of the FS board for $50.00. It weighs several pounds less than the OEM balancer pulley and is obviously far more advantageous for small gains coming from the reduced rotating mass than the March pulley (or any other piggyback design) which add more rotating mass to the rotating assembly. I think the percentage of reduction is around 33% IIRC. I would only reccomend the ASP UDP assuming one got the thing cheap and he were at peace with what it will do.
There is an obvious gain here but as many have said, I would expect it to be, and have accepted that the gains, are very tiny. I also have zero issues with charging and AC performance. Bottom line on it, I would never invest the money for a new one considering the expected gains but for someone who races, all of these nickle and dime power gains do eventually add up.
Regarding the EWP. I dont have one and would not run one becasue I prefer to have better reliability than the gains it would provide for mostly a Sunday drive car.
How does the engine not drive an electric waterpump?
The engine turns the alternator which runs all of the electricals.
They free up power by moving far less water.
Far as failure modes the electric is pretty likely to just stop working as it's failure mode, the mechanical is most likely to weep making the belt slip when you try and use the power steering, alerting you LONG before there is any risk of overheating.
The engine turns the alternator which runs all of the electricals.
They free up power by moving far less water.
Far as failure modes the electric is pretty likely to just stop working as it's failure mode, the mechanical is most likely to weep making the belt slip when you try and use the power steering, alerting you LONG before there is any risk of overheating.
Last edited by wrd1972; Oct 2, 2011 at 02:35 PM.
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the alternator, on my car, puts out 135 amps.This powers whatever electrical (radio, headlights, etc.) and in my case a EWP. the 7 amps the EWP draws does not = in any way the mechanical power it takes to turn a gear or belt driven accessory. This is why it frees up horsepower just like pulling the belt at the track to free the motor from turning the accessorys. Just like running headlights at the track on night race....my times are no slower because of the "drain" on my electrical system.
yes if for some reason the EWP loses power it will stop working/cooling immediately. Mechanical or electric KEEP YOUR EYES ON YOUR GAUGES.
I am not saying a EWP is "best" but for me it has worked very well for 13 years.
Personally I would not want any mod that "requires" me to keep an eye on the gauges. I will assume thats much easier said than done and I doubt anyone is capable of doing it all of the time. Also the idiot lights are so subtle they can be easily missed during the day in the sunlight.
If I were to have an EWP personally, I would rig up a small motorcycle alarm siren or some other audible indicator that would absolutely get my attention the second a failure occurred. I have never unserstood why the manufactures dont already do this with engine temps and oil pressures.
If I were to have an EWP personally, I would rig up a small motorcycle alarm siren or some other audible indicator that would absolutely get my attention the second a failure occurred. I have never unserstood why the manufactures dont already do this with engine temps and oil pressures.
I have an EWP on my 96 ta and haven't ever had an issue with it in the past 6 years it's been on the car.
I can see the other negative "points" that the others have posted and they may be valid but, for everyone of their negative points there are also positive ones.
If you subscribe to the "every little bit counts" theory then the ewp and udp are good choices but I never did see and SOTP gain from either.
When I ran the UDP I got stuck in line to get in at the drags one night for about an hour with the car just idleing and moving a few inches ever few minutes. Once I got parked and came back to start the car later it was dead. So, if you are going to run the UDP, makes sure you get the overdrive pulley for the alt. if you do an sort of city/traffic driving. It's not worth the worry if you just get the UDP and get stuck somewhere.
I say go for both UDP and EWP, I'd do them both all over again. The headers are by far a much wiser investment though.
I can see the other negative "points" that the others have posted and they may be valid but, for everyone of their negative points there are also positive ones.
If you subscribe to the "every little bit counts" theory then the ewp and udp are good choices but I never did see and SOTP gain from either.
When I ran the UDP I got stuck in line to get in at the drags one night for about an hour with the car just idleing and moving a few inches ever few minutes. Once I got parked and came back to start the car later it was dead. So, if you are going to run the UDP, makes sure you get the overdrive pulley for the alt. if you do an sort of city/traffic driving. It's not worth the worry if you just get the UDP and get stuck somewhere.
I say go for both UDP and EWP, I'd do them both all over again. The headers are by far a much wiser investment though.
dwayne, I meant the motor does not drive the WP by gear or belt as in mechanical pumps.
the alternator, on my car, puts out 135 amps.This powers whatever electrical (radio, headlights, etc.) and in my case a EWP. the 7 amps the EWP draws does not = in any way the mechanical power it takes to turn a gear or belt driven accessory. This is why it frees up horsepower just like pulling the belt at the track to free the motor from turning the accessorys. Just like running headlights at the track on night race....my times are no slower because of the "drain" on my electrical system.
yes if for some reason the EWP loses power it will stop working/cooling immediately. Mechanical or electric KEEP YOUR EYES ON YOUR GAUGES.
I am not saying a EWP is "best" but for me it has worked very well for 13 years.
the alternator, on my car, puts out 135 amps.This powers whatever electrical (radio, headlights, etc.) and in my case a EWP. the 7 amps the EWP draws does not = in any way the mechanical power it takes to turn a gear or belt driven accessory. This is why it frees up horsepower just like pulling the belt at the track to free the motor from turning the accessorys. Just like running headlights at the track on night race....my times are no slower because of the "drain" on my electrical system.
yes if for some reason the EWP loses power it will stop working/cooling immediately. Mechanical or electric KEEP YOUR EYES ON YOUR GAUGES.
I am not saying a EWP is "best" but for me it has worked very well for 13 years.
You sit at a desk for a living don't you? No comprehension of how things function, a very sad epidemic.
The electric pump draws far less power from the engine than mechanical because it moves far less water at mid to high rpms, any belief to the contrary is belief in perpetual motion. You can not change forms of energy and get more work back out of it.
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10-12 rwhp sounds about right, the only two pieces I installed without hitting the dyno. I run the ASP 945103 dampner set also. It is 3 lbs. lighter than stock and has been dyno'd by 2 op and verified the gain of 5 and 6 rwhp. Going on 8 years of use with a 10 year old battery and never had an issue. I put the CSI pump on at the same time and between the two I could tell a big difference. I'm on my second pump and knew for two weeks the ewp was failing. Like most things it made noise for the two weeks before blowing the fuse. I highly recommend the two, if you don't have them you're missing out. I have a 3900# car with a '93 LT1/ 4l60, a few bolt-ons and a best 12.82 et. Through shorties, go figure.
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From: Clearwater
You sit at a desk for a living don't you? No comprehension of how things function, a very sad epidemic.
The electric pump draws far less power from the engine than mechanical because it moves far less water at mid to high rpms, any belief to the contrary is belief in perpetual motion. You can not change forms of energy and get more work back out of it.
The electric pump draws far less power from the engine than mechanical because it moves far less water at mid to high rpms, any belief to the contrary is belief in perpetual motion. You can not change forms of energy and get more work back out of it.
my interpretation of his reasoning is that it does not take any more mechanical energy from the engine to pull an additional 7 amps from an alternator that is no harder to spin whether the load on it is 0 or the whole 135 amps.
Again someone not capable of anything resembling basic comprehension.
Ever jump start another vehicle? Notice how the running one's idle hiccups when the connection is made? That is the extra load being pulled from the alternator, on old carbed stuff with no idle control it would lower the idle due to load.
The alternator can not pull a whole lot of load on the engine though rather than hold your hand through this and have you ignore it go out on the internet and search for conversion tables, you can convert amps at volts to HP.
There is SAE published data on the mechanical pump using 11 hp to move 66gpm though the closed cooling system.
The electrics are freeflow rated, being an impeller not a positive displacement pump restriction means a LOT. Many have documented increased cruise temps from the electrics if they view through the pcm rather than the dash.
They have their place, BUT IMO it is for cars looking for that last .1 at the track.
I have put over 250K miles on my LT1 cars all after buying them used, I know my way around this stuff.
Another point for mechanical vs electric is either you should buy TWO electrics so you have a spare, a mechanical gives you more warning and you can get them local 7 days a week.
Ever jump start another vehicle? Notice how the running one's idle hiccups when the connection is made? That is the extra load being pulled from the alternator, on old carbed stuff with no idle control it would lower the idle due to load.
The alternator can not pull a whole lot of load on the engine though rather than hold your hand through this and have you ignore it go out on the internet and search for conversion tables, you can convert amps at volts to HP.
There is SAE published data on the mechanical pump using 11 hp to move 66gpm though the closed cooling system.
The electrics are freeflow rated, being an impeller not a positive displacement pump restriction means a LOT. Many have documented increased cruise temps from the electrics if they view through the pcm rather than the dash.
They have their place, BUT IMO it is for cars looking for that last .1 at the track.
I have put over 250K miles on my LT1 cars all after buying them used, I know my way around this stuff.
Another point for mechanical vs electric is either you should buy TWO electrics so you have a spare, a mechanical gives you more warning and you can get them local 7 days a week.
I don't understand why this guy always has nothing but negative things to say. No one insulted you, no one said you don't know what you're talking about, yet you enter the thread with a bad attitude being super rude.
From someone who actually has a fast b-body I would not recommend either on a mild street car. But I just know what I am talking about and actually put together a fast b-body.
The underdrive is not worth it because since the belt doesn't turn even the mechanical pump the potential gains are small. Removing the belt all together is only worth .1 at the track.
The electric pumps move LESS water at mid to high rpms and their failure mod is MUCH more dangerous than the mechanical.
The underdrive is not worth it because since the belt doesn't turn even the mechanical pump the potential gains are small. Removing the belt all together is only worth .1 at the track.
The electric pumps move LESS water at mid to high rpms and their failure mod is MUCH more dangerous than the mechanical.
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From: Clearwater
Originally Posted by 96capricemgr
Again someone not capable of anything resembling basic comprehension.
Originally Posted by 96capricemgr
Ever jump start another vehicle? Notice how the running one's idle hiccups when the connection is made? That is the extra load being pulled from the alternator, on old carbed stuff with no idle control it would lower the idle due to load.
Originally Posted by 96capricemgr
The alternator can not pull a whole lot of load on the engine though rather than hold your hand through this and have you ignore it go out on the internet and search for conversion tables, you can convert amps at volts to HP.
There is SAE published data on the mechanical pump using 11 hp to move 66gpm though the closed cooling system.
The electrics are freeflow rated, being an impeller not a positive displacement pump restriction means a LOT. Many have documented increased cruise temps from the electrics if they view through the pcm rather than the dash.
There is SAE published data on the mechanical pump using 11 hp to move 66gpm though the closed cooling system.
The electrics are freeflow rated, being an impeller not a positive displacement pump restriction means a LOT. Many have documented increased cruise temps from the electrics if they view through the pcm rather than the dash.
I have both mods, I got the pulley used a long time ago, I would guess it has to be worth a few hp, maybe not 5 or more but 2-3 maybe. It was one of the first boltons I did. As far as the EWP, I like that I was able to run a less expensive heavy duty timing set, plus it takes strain off the cam/timing gears at high rpm. I wouldn't run an EWP if I daily drove it though, it's a much better suited for a weekend/track car.