Electric water pump EWP options for LT5?

[5ABI VT]

Im interested in a radiator upgrade over the winter and will move to an electric water pump. Ive read a lot about the bypass and it worries me because doing a full throttle run from 1-4th on a runway and the coolant is bypassed pretty much the entire time. I really don't like that thought very much. Makes me wonder to be honest how hot the temps are getting by the time Im in 4th gear and how much timing is being pulled.

On the LTx the pump sits on the waterpump face. Ive heard of in line pumps as well. Has anyone used 2 inline pumps one to and from the rad?

[Paul Workman]

I think Pete said an electric pump was worth about 12 hp savings. However, following his experience with an un-sensored electric pump failure w/o warning and consequent engine overheating damage, I'd not install one w/o a sensor to monitor pump operation and give warning if the pump failed.

Far as overheating in the 1/4 (under 13 seconds) drags or 1/2 mile WANNAGOFAST runway events (1-4 gears in ≈ 20ish sec.) I didn't have any heating issues when starting out at 200-205ºF. (My bigger concern was stopping!!)

If you were operating in a sustained 5500+rpm condition, that would be a concern, far as cavitation goes. However, parasitic drag losses occurring way before cavitation, would be invoking the need for under-drive pulleys (or the like).

[efnfast]

It's not like the radiator goes into total bypass. The water pump hits about 100 gpm at high rpm, whatever the rad can't handle goes around.

[5ABI VT]

Anyone have photos of what the bypass looks like ? I might need to look into the under drive Pullies. I watched the tach on a few runs and it's over 6 k the entire time. I have a HD Meziere on my 93 non z and with my last motor a 388ci lt4 solid roller I had excellent coolant temps throughout its life and that's with a stock rad that had never been cleaned either. With my z I have a strong alternator that is performing admirably and can easily handle an ewp or 2 added to the system

[Karl]

I have an under drive lightweight water pump pulley. From my understanding it raised the bypass feature ~500 rpm or so.

I decided to go this route after talking with Pete. I figure the pulley is worth ~7 hp and that is good enough for me.

Talk to Pete like others have suggested.

[rkreigh]

you need an electric pump that will flow about 80 GPM

it's better to go with a good rad and monkey with underdrive pulleys and the bypass

the electric is great for drag racing, and frees up some HP, but I'm not sure how well it would work for sustained WOT like ORR

probably fine for flying mile and such.

Pete for sure would know, he's experimented quite a bit there!

I'd trust his judgement and recommendations for sure.

[RussMcB]

Originally Posted by rkreigh

the electric is great for drag racing, and frees up some HP, but I'm not sure how well it would work for sustained WOT like ORR

probably fine for flying mile and such.

My gut feeling is an EWP would be great for road racing / track days because (if you're pushing it) you are over 5,500 RPM most of the time.

[5ABI VT]

Definitely will ask him. I was under the impression after some reading the bypass prevented all coolant from circulating... Even if it wasn't all of the coolant it would only make sense that cylinder head temps would rise very very fast under wot. Ive seen an ewp be off and temps rise at idle steadily I can only imagine wot would be producing a ton more heat.

[5ABI VT]

My thoughts are to use the full power light for ewp 'on' or to wire in an LED under the cupholder lid/cover so I can keep an eye on wether or not its functioning. Again I had a mezziere on my 93 LT1 car with a 388 solid roller motor that saw 8k rpm on every shift and several top speed runs.. with a stock uncleaned rad (at least since I bought it in 98) and never had any coolant temp issues at all. Just oil temps would rise after extended high rpm cruising/wot.