Effect of a 38mm restrictor on an LS7

Yes, there was a sudden rash of V8 'charged conversions. And then a sudden rush on new gearbox and drivetrain bits shortly after...some of them still aren't reliable
RE: The motor just stick it back in with some thicker oil for a year!

Update time

I sold the LS7 and, unfortunately, the price of new ones has gone up by £2000.

I've been looking at the viability of buying a base spec LS3 for £6k less and fitting a cam that is more suited to running with the restrictor.

I've been recommended this spec by Cam Motion

Duration at .050": 216/224
116 Lobe Center Angle with a 113 Intake Centerline
Lift with 1.7 Rocker Arm Ratio: .595"/.587.
Double spring kit with titanium retainers.
Severe duty timing chain using stock gears

Google tells me standard is 204/211 .551/.525 117

The other issues I have are sump clearance, a standard sump will foul my propshaft and the risk of oil starvation

I'm thinking of importing this sump which is shallow enough, has baffles and trapdoors.

They also do a bolt on adapter so that I could easily fit an Accusump. I don't want to fit a dry sump, I have no space for an external pump and the belts are vulnerable with off road racing.

Then I'm thinking have it mapped on a rolling road.

Does this all sound like a reasonable way forward?

What's the price of that package out of interest and you did notice it uses cast pistons?

Is the Vette sump not regarded as one of the best and lowest profile ? I thought the LS2 shallow was one of the worst ?

http://www.improvedracing.com/baffled-oil-pans/baf...

As for changing cams and springs etc....why not just try the engine as is from the factory first and then see how things go ? They will all be very much endurance tested, so you could thrash it all day long and be confident with reliability.

Although yes no doubt, a cam upgrade is bound to help performance, especially with sucking through a little restrictor as long as you can get somewhere up to the job of retuning the factory ecu ok to suit this.

Thanks, I'll look at that sump. I'm struggling to find comprehensive measurements but I'll see if we're in the right ball park. As the car is spaceframed there are tubes in the area.

Thinking with replacing the cam etc. is that it's a lot easier with the engine out, access to the top end is tight once the engines in. Also I want to get as near to the LS7 performance as I can, I'm trying to race rather than just take part.

I prefer OEM reliability. From what I can see the different versions of LS3 offered by GM are achieved solely with a cam change, so it seems to make sense to fit a cam that works for my application, with the 42mm restrictor.

I assume the LS3 at 6.2 litres will rev slightly higher than 7 litre LS7 with same restrictor?

Big wing sumps are appx 53 cms wide and 12 cms deep so pretty close to your measurements. The second version with a detachable bottom cover is slightly bigger. An ls7 dry sump will be about 12 cms deep but I've not measured it.

Initially I was going to fabricate one until I saw the improved racing ones.

Do you know how well the cast ali welds? Or is it easier to start from scratch.

I had rather convinced myself that a shallow sump with Accusump would be OK.

As you say we don't now the g forces or how well the oiling will work so it's guess work and balancing the amount of work against a perceived risk.

I have no doubt that the biggest risk of starvation comes on deceleration. The engine is in rear so the oil will be flowing towards the sump well.

I don't know how well Accusumps work

Modified LS2 sump seems like the way ahead. I've ordered the cam and other bits.

Off topic but could I ask where best to try and buy this clamp? It's from the turbo of a DAF CF65 lorry, between the 'in' and 'out' parts. DAF don't list it as a separate part and I don't know what make the turbo is

Thanks

They don't ship to the UK but once I knew they were called V clamps I found the right size on ebay for £13 delivered.