ScaryFast

I have an LS6 from a 2005 CTS-V. Now I need to get a pan and oil pump. I understand the C5Z pan is adequate for what we do. Is this specific to the Z06 or did all C5 Corvettes have the same pan? All the ones I've seen for sale say they work for LS1 and LS6 - as long as it's the winged pan I'm good, correct?

Also, what is the oil pump I should use for a stock LS6? Is the stock pump good or is an upgrade required for racing?

Thanks guys. And of course if anyone has either of these parts up for sale shoot me a PM...

travisnd

1. GM LS4 high volume pump

• Does the same thing as the Melling high volume pump at a fraction of the price
  
• Been using one since they came out back in '07 with no issues
  
• Had the original one with the 52lb relief spring on my old Z06. Have the newer one with the 42lb relief spring in the current race car. Prefer the latest one as I felt the old one had a little too much oil pressure.
  
• I see low 40s at hot idle and it never gets under 50psi on track when hot. I do have a DRM oil cooler kit with the Setrab 625 cooler.

2. The later LS1/LS6 2-piece pans are the same

Kubs

There is a pan in the C4 section for some reason.

geerookie

This is the way to go.

ScaryFast

Where do you get the LS5, from Rock auto or something? I did an ebay search and got all Melling versions...

travisnd

Here you go...

http://sdparts.com/details/gm-factor...parts/12612289

Disregard the warning on there. A Corvette pan with an oil cooler will have no issues. When the pump first came out there were some stories on LS1tech of F-body guys pumping too much oil to the top of the engine and losing oil pressure.

0Louis @ LG Motorsports

We stay away from the high volume pump, because the LS4 has some displacement on demand stuff that requires a stronger pump. We do however, shim the factory LS6 pump 60 thou, or 100 thou depending on the application.

There were some issues with pumps from different applications draining pans.

travisnd

Sorry but I disagree with you 100% on this one. The LS4 does the same thing as the Melling pump that so many rave about. Yes there were a few posts on LS1tech about F-body (less oil capacity) guys draining the pan too quickly with the early LS4 pump with the 52lb relief spring. However, these cars were supposedly using stock pans and didn't have any oil cooler setup. Furthermore, I can't remember any specific cases with examples, just a few posts warning against it.

I put the older pump with the 52lb relief spring in my old Z06 when I put one of your cams in it. I put nearly 20k miles on it including 5-6 track weekends w/o issues. I was running a Dewitt's radiator with a left side EOC. With the stock pump I'd get a "LOW OIL PRESSURE" warning at start-up after the oil cooler install. With the LS4 pump that went away and I'd get 49-51 PSI at hot idle and it'd never go below 50 on track even with oil in the mid 270s.

On the current race car I went with the newer pump with the 42lb relief spring. I see low 40s hot idle and never goes below 50 on track with oil temps around 260 max. I run a DRM stand-alone cooler with the Setrab 625 cooler. Been racing the car for almost 2 years now w/o issue.

Personally I feel the higher-volume pump is added insurance with the oil cooler added to the oiling circuit and I see no downsides.

Just my $0.02

0Louis @ LG Motorsports

Its OK to disagree, you are one of the first ive seen good results from regarding that pump, which is good to know. We have done some testing regarding those pumps ( LS in general) and stuck with the LS6/LS3 with a shim. Same thing used in the WC cars that have the stock pump for pressure, and the Grand am Continental cars too

The LS3 pump is popular too, which is the same pump between the Z51 and non Z51, one has the cooler, one does not.

As long as oil pressure is good on track ( +50-80) I think any of the pumps will work well.

I do agree that one should be cautious of oil pressure and temperature ALL the time.

0Louis @ LG Motorsports

Id also like to add, that in some extreme race apps, we run no relief, and use an external regulator.

ScaryFast

Where would you put this shim? I'm new to the LS world...

travisnd

They shim the pressure relief spring so it opens later thereby allowing the pump to create more pressure before going into bypass.

The high volume pumps have a different gerotor design that actually moves more oil volume with each revolution.

mfilippello

funny I should find this thread as I am researching this right now. I had an LS4 pump in my LS1 when they 1st came out. Motor has heads and cam but stock bottom end with Fbody pan. No oil cooler. Its a swap in a RX7. When I had the Ls4 pump, It would peg my oil pressure gauge at WOT. I have DEFI gauges with play back. goes to 140psi. Replaced the pump with stock ls6 pump and now 80psi max with 35 idle. No shim.

I am getting ready to drop a stroked LS3 in the car. Deciding what pump to put in. I plan on tracking the car at Sebring. Took it out once already with current motor. Oil pressure drops under hard cornering. I even have the improved racing trap door oil pan baffle. I still was loosing pressure in hard corners. I am running r compund tires.

Anyway, I have two pumps at shop. A ported LS6 which I got with my ATI balancer, and a melling high volume pump (10296). I opened both up to check for casting flaws and compare. You know what, no difference. The gear rotors are exactly the same. You can lay them on top of each other and swap them back and forth. Other than the spring which just sets the peak oil pressure, I see no difference in volume capability. what a scam. I remember the LS4 pump being different. Maybe the melling flows 18% more than the original LS1 pump or something but not the GM LS6 pump I have. Like I said. Gears are identical.

Question is, should i run the higher pressure spring that came with the Melling or the stock spring. Oil issue could be oil trapped in heads as suggested. trying to remedy this issue.

Mike

travisnd

FWIW the newer LS4 pump has a 42 psi relief spring. Racing at RA last weekend with oil temp at 269 max my pressure stayed in the 60s at WOT.

RX-Ben

Pegging at 140 means something is wrong. Are you sure you have the gauge properly calibrated? The LS4 will boost oil pressures, but nothing like that.

The Melling should have 2mm thicker gears, but should otherwise be identical.

mfilippello

You are correct good sir. The stock gear is 10.7mm thick, the Melling is 12.7mm. Missed that detail. Feel better about Melling pump now.

Gauges were working fine. I did nothing but change pump and oil pressure went back to normal. Maybe bypass was stuck or deffective. I always do seem to get the bad new stuff. That is why I went through these pumps.

Mike

ScaryFast

I went with the 12612289 LS4 pump and had the car on the road for the first time last night. I was seeing seriously high (in my mind) oil pressure; 50 - 60 at cold idle (Mobil 1 10W-30) and 80 psi at cold driving, maybe 3000 RPM around the service drive behind the shop. The oil temp guage never moved so oil never got above 100 degrees, but that still seemed high to me.

I am used to 40 psi idle and 60 psi WOT with the LT1, are the numbers above normal for LS motors? Mine is a stock LS6, 15k miles with a remote filter and oil cooler.

RX-Ben

That is what I saw when I put an LS4 pump in my LS6. No need to worry. It will drop a bit once the oil gets up to temp.

sebdavid

Huh? I'm seeing 30psi pretty constant when up to temp on track. Apparently it's within GM spec (10psi per 2000rpm), now you have me worried!

Consensus?

sabastian458

My cluster gauge reads 75ish at cold oil and 2200 rpms. 40's at idle cold. Amsoil 10w30.

Next time I go in there I think I might put the newer LS4 and go with a 5w-20 oil. I'd rather be a lil high at cold than a lil lower than comfort when at higher temps.