You will need to change the studs from the metric ones you have now, to 7/16 or 3/8 studs, depending on which rockers you go with. You should change the springs, and I think the only ones available are not self aligning, so you will need guide plates and hardened pushrods. All of this can be done with the heads on. To change the springs, you need a spring compression tool designed to work on the vehicle and a air compressor with a sparkplug adapter to keep the valves up.


Edit to add the following. Here is a link to a forum member who has done a lot of testing of various parts and shows a lot of results. Its a LT1 but most all applies to your LT4 as well. http://www.wku.edu/~nathan.plemons/h...rformance.html

 

Amen!

There really is more to fast driving than just increased power...

I can see where an electric pump would be an advantage on a drag (and possibly a short-course autox) car...especially if you can switch the alternator off so the electric pump is being powered by the battery instead of the engine through the alt.... but not where it would be an advantage on a street/track car.
Am I missing something?

Larry
code5coupe

 

FWIW, IMO the 3 main advantages to the electric pump are
1. more reliable. It eliminates the weep hole.
2. you can use a standard double roller timing chain
3. at the drag strip you can turn on the pump and fans, leave the motor off, and cool it down real fast.

I wouldnt do it for a hp gain but I do believe there is a small gain there in the upper rpms.

 

...with one caveat: the stock pump is dead reliable; but it can make the Opti a little less so.

Larry
code5coupe

 

.......and when the stock pump starts to fail it will give you warning. When the e. pump fails, you are stuck on the side of the road.

 

Their life expectancy is 2500+ hours. If you were to install one on a car and drive at 60mph till the life expectancy is up, you'd have to drive 150,000 miles.

As to electrical draw, we are only talking about 8 amps. You could easily draw that much with an upgrade sound system, an aftermarket computer system, better head lights, a better ignition system, better fog lights, better fans....


You wouldn't want your car to have the ability to cool down when sitting at a stop light, or in stop in go traffic or in the pits in line before a 1/4 mile run?

One of the advantages of an electrical water pump is you get the pumps maximum rate at idle, so coupled with fans set to come on earlier or manually controlled, you can cool the car down quickly during down times.


Its going to have increased cooling. Yes, it has the same flow that it does at idle, but that is more than a mechanical pump at max rpm.

The HD meziere pump is rated at 55 GPM, which as far as I can tell (I haven't been able to find a definitive chart of flow rates of a stock LT1 mechanical water pump) the HD pump out flows a mechanical pump at all times, even at high rpm's.

Using your logic we should go back to mechanical fans, because they will be drawing more electrical power at idle, and will be turning at the same rate at max rpm as at idle. But yet our cars came from the factory with electrical fans, and pretty much every car in the last 20+ years at least has come with electric fans.

Just because your turning some electrically versus mechanically doesn't mean that you have to lose horsepower. An electric motor can be very efficient at its one job, more so than a mechanical component that has to be able to move sufficient rates at very different rpm's. An electric water pump's impeller can be designed to be extremely efficient for its one rpm, and thus a fairly lower draw motor can be employed. A mechanical water pump impeller must be able to move sufficient amounts of water at both very low rpm's (idle) to very high rpm's (6400+) and there will have to be sacrifices to achieve that.

I have a 10% under drive crank pulley, with my idle bumped to 850rpm, and even with 100/80w headlights and an electric water pump, upgraded fogs, upgraded sound system, LTCC LS1 coil system, I still don't have a problem with the stock alternator at idle at night.

 

The only under drive pulley that I know of is the 10% under drive harmonic dampener from ATI.

 

That's how I see it. But, hey, I could be wrong!

Larry
code5coupe

 

Do you still have it? Is it in good shape? I want it...

 

Oh, and weren't we talking about water pumps or something?

I have the Meziere HD in my race car. It's necessary for two reasons - increased flow (55 GPM) and because it's hardwired to a switch (along with the fans) so I can cool the car between sessions quickly with the engine off. Of course my tiny lightweight battery doesn't have enough juice to leave it on too long or the car won't start...

If you want to increase your car's reliability at the Auto-x track get an EP. Don't do it because someone told you it adds 7 hp.

Oh, and let's not forget it makes changing coolant a snap. I unplug the hose to the fill resivoir, route it into a bucket, turn on the pump, and pump it dry. Once it gets low I have to keep adding water to get it all out, but that's what the InstantOil Change monkeys call a "radiator flush" and charge you $150 to do.

 

I don't why folks continue to claim no HP increases for exhaust...I went from stock to Corsa for a 17 WHEEL horse power gain...dyno proven...same dyno...same operator...similar days even though all corrected.

HOT cam gave me an additional 26 WHEEL horse power...again same dyno/operator...factory tune.

CNC heads got me another 33...

I agree with the above 4.10's are the way to go...just hurts topend, but rarely anyone uses it anyway...

 

I have had mine now for 3 years with no problems. It seems to me that most complaints have been with the relay or fuse assy. and not the pump. I use a heavy insulated inline fuse holder and I ordered a orig. equipment style fan relay kit which is more waterproof then most aftermarket relays. Also, the fans are rated at a higher amp draw then the pump, so the relay is plenty strong. But with the exception of leaking I dont doubt that the mech. pump is more reliable. But heck, if I was wanting reliability I would not have purchased a corvette. :o Now watch everybody flame me!!

 

Your numbers are well documented and I dont doubt them. But for me, using the drag strip for testing, I gained nothing going from the stock system tied to the long tube headers to the magnaflow mufflers. Now I dont know if the stock resonator is hurting me but I intend to replace it with a x pipe this year so who knows. The pipes are already 2&3/4 from the factory.
The numbers in my signature are with the stock exhaust and when comparing them to others on here with similar mods I just dont believe the exhaust is hold me back.
The main hp gains with the LT1 is heads, cam, and long tube headers.

Oh, just wanted to add. Mr Mojo has done a lot of track testing with stock vs muff. eliminators vs corsa and I dont think he has seen much of a difference on his.

 

I don't think its lack of airflow. Yes, I do think its part of it, but I don't think its the whole difference.

With my elec water pump and a 160 t-stat and my Dewitts radiator my car stays at 170 - 175 degrees at all times. Sitting in traffic, idleing parked, or driving down the highway, it doesn't change. With my stock LT4 with 180 t-stat and stock radiator my car would heat up anytime I stopped moving, and then cool down again once I started moving again.

Ignoring the change in T-stat the only changes are the radiator and the water pump. I don't think that the Dewitts made THAT big of a difference, and I haven't read of anyone with a Dewitts that has seen that big of a difference. I think that it is the elec water pump that is making the difference because now at idle my car is able to pump much more water throught the radiator setup.

If someone has put on an elec water pump and didn't do any other changes they would be able to tell us if thats the difference.

Another way to test this would be to know what your normal temp running down the highway is, and after idleing for a while to bring the rpm's up for a few minutes and see if the temperature goes down. You'd add more heat to the engine, but it might tell you if the water pump pumping more water alone could make a difference.

Another test would be if you had really powerful radiator fans, close enough to simulate moving and idled the car and saw how much your temperature changed.


Then why do people make more RWHP when using an electric waterpump?


I haven't run my car really hard for a long time, but I've never seen it heat up more than a few degrees no matter what I do. 55 GPM is quite a lot, and I have a hard time believing the stock puts out that much or more.

I'd like to see a flow sheet at different rpm's for the stock.

Then where does the rear wheel horse power come from when people convert to an electric water pump?

The electric water pump only requires a very small amount of hp to run no matter what speed the engine is running. That requirement is what amount of extra hp the alterantor takes to produce the extra 8amps to run it.

Assuming a 140amp alternator and the manufactors published 8amp draw, thats only 5% of the alternators total peak production ability. Thats hardly an alot of extra load on an alternator.

The mechanical pump on the other hand is not going to be nearly as efficent because it has to be designed to work all throught the rpm range. If people are putting out more RWHP with an electric waterpump, that tell us the mechanical HAS to be less efficent.

A mechanical water pump should require x% of total engine power to run, where as a electric will require xhp at all times. It doesn't take long for a small % to quickly become much larger than the hp required to make 8amps. That's why people put out more RWHP when using an electric waterpump.


Then how would you explain these results?

Yes, electric fans mount very nicely, and they are quite useful in a transversly mounted engine. Yes they are very cheap and they can be configured to do the job.

But if overall power was the goal, I believe the corvette engineers could have configured the C4 C5 or C6 to use a mechanical fan if it made more power.

Why doesn't the C5R or C6R use a mechanical fan then? They would be after every horsepower they can get.


Of course. Nothing is 100% efficent. But some systems are more efficent that others. We have to power the waterpump somehow.

Drawing power from an alternator doesn't take much power. (Link).

According to tests from that link drawing 65amps off a 100amp alternator required only 1.28hp.

Some fans I've found on the internet only draw 6 - 10 amps each. That means they would require only around .12hp to run. That's about how much an electricity an electric waterpump would require to run.

Look at small portable generators. They can generator 3000 watts off a 5hp engine.

Please explain to me how you account for the increase in RWHP on a dyno or a decrease in time on the track by cars that are running electric waterpumps?



Efficencies are great and all, but the fact is that there are cars out there going faster and putting more power to the wheels with an electric waterpump. How else do you account for that? I can see no other way besides a decrease in temperature or an increase in effency.

People are make more RWHP with electric water pumps. Why is that?

 

Has anyone put 1.7 rockers on a vett that already has an LT4 though? If so what kind of power diference was there?

 

I dont know anyone who has, Nathans car is the closest to it I know. He had the larger valves and the lt4 hotcam. And dynoed 14hp increase at the rear wheels with the 1.7 vs. 1.6 change.
I remember 96 red coupe switched out from stock to 1.6 and gained 2 tenths at the track. He is like Mr. Mojo and very accurate with his data. But we would have to factor in that not only did he go up from 1.5 to 1.6 he also went to a roller rocker.

 

Here's my take as it pertains to the LT4. The LT4 heads peak flow is in the .500 - .550 lift range, but the stock LT4 cam (with 1.6's) has a .47x lift, right. So, by going to a 1.7 rocker, you increase the amount of lift to coincide more with the flow characteristics of the LT4 heads. I'm sure 15-20hp can be found in this mod.

 

Cold B....don't let rocco16 get you too worked up.

I doubt he knows what he's talking about since his extensive mod list contains aftermarket headlight bulbs and a shift ****

 

Thanks

I don't have a problem with him at all. I've been enjoying our little debate here.

I've learned alot on this forum by just reading posts between people debating different things, so I know it will help someone else better understand what the difference is and why.

I have been known to be wrong on things in the past and I would always like to be corrected when I am so I can learn. I always enjoy a technical discussion when facts are brought to the table to support a conclusion. I enjoy finding out why and how things work, and finding the relationships between objects. That's why I am so good at what I do professionally. I can find the hidden relationship between to seemingly non-connected things.

We have complex cars, and modifying them only makes them more complex and complicated. But it can give us better performance and fix factory shortcomings.

On this forum we have alot of knowledge on what works and what doesn't, and on what would be a better solution to a problem. What some people here have done to their cars is amazing, and I stand in awe of them. What I lack in personal wrenching skill I like to think I make up for in knowledge and understanding. I enjoy learning from this forum and its the discussion between members that makes that possible for all.

 

My car is a bolt-on LT4, so I can share my experience. I'd go in the following order:
4.10 gears
Long tube headers and exhaust work
Dyno tune it
Electric Water pump...

...and say hello to a mid to low 12 second ride and a major lack of traction on street tires

Oh, and the electric water pump makes a noticeable power difference, believe it or not.