Gdi plus pfi injection

[Hq King]

Has anyone done or know how or who does duel injection for the ls3 as I understand the port injection is for the low to medium throttle and direct is medium to high throttle

 

[rognvald261]

Has anyone done or know how or who does duel injection for the ls3 as I understand the port injection is for the low to medium throttle and direct is medium to high throttle

Direct injection in GM speak is SIDI, the fifth V8 engine generation called EcoTec3 is SIDI, but the head doesn’t fit our fourth generation engines. At all.
The advantage if any is at high compression under load, better control at lower temperatures for emissions, not really performance as you infer.
A bloke who used to post here did some research into high compression high pressure fuelling using GenIV port injection, uploaded some SAE docs including this one which show exactly where LS actually beats the LT SIDI in certain regard.

 

[abuch47]

So all that VVT and AFM is possible for the LS3?

 

[FPFQ_king]

So all that VVT and AFM is possible for the LS3?

yes, been done successfully by PIR4TE, full write up on FaceBook.

 

[abuch47]

yes, been done successfully by PIR4TE, full write up on FaceBook.

I thought his was the 6l L77 LS2 derivative with AFM/ethanol from factory?

looks like there is a l99 which is the ls3 derivative.

 

[Skylarking]

@Hq King your question should really be structured around what you want to achieve as there may be better alternatives.

Direct injection is simply a more expensive option and my guess is that manufacturers would use it due to its tighter fueling control allowing compliance with pollution laws (with the added benefit of reduced fuel consumption). Such systems would be used where port injection would otherwise not meet such pollution laws.

Ford uses port and direct injection in their new mustang as does GM in the new US Cameron SS but not sure which engine the older aussie (HSV convert) Cameron has in it.

Cost wise, who knows how much it would be to retrofit port and direct injection with VVT and AFM to an old LS3. But GM has done the work and it’s called an LT1.

My guess is that a LT1 crate engine would be a better bet, though getting it to play well with the VF ECU, TCM, BCM, etc could be somewhat interesting.

If you go the LT1 crate route, i doubt you’d have much change from $20k (ok I admit the figures are pulled out from a dark place). But on the www, I have seen LT1 crate engine @ $10k and you’d still need LT1 ECU + clutch bits + bellhousing to match your gearbox + other bits you may not be able to pinch from your LS3 and probably some custom fabrication. So it will quickly mount up - for around a 340kw engine? Does it make sense?

May be, buy the next Camaro with its standard LT1 when it finally comes out in NZed Or put a cam, headers, etc in your LS3 if you are chasing power If you want economy, well that’s a bit of an oxymoron when used in a sentence with V8

 

[FPFQ_king]

I thought his was the 6l L77 LS2 derivative with AFM/ethanol from factory?
looks like there is a l99 which is the ls3 derivative.

I don’t know how to answer that briefly, L77 is not an LS2 particularly the heads which what the OP is talking about, ethanol has nothing to do with it, L77 and L99 and LS3 share same heads, all VVT single bolt cam core.
Anyway what you do to L76, L77, L99 or LS3 or LS7 is exactly the same for VVT, to retrofit AFM to LS3 is not worth it.
EDIT: is an LS7 bore BTW (6.4 litre) in standard block with standard LS stroke

 

[FPFQ_king]

If you want economy, well that’s a bit of an oxymoron when used in a sentence with V8

Stock LT1 gets 27 MPG combined (8.7l/100k) combined, down to 5.5l/100k on highway in the Stingray. Essentially is AFM and VVT.
There are plenty of well documented low consumption / high output videos available, Gen IV with AFM and VVT can go as low as 3l/100k highway using cooled EGR method incorporated in the tune.

 

[Immortality]

Isn't it interesting that it looks like GM have deactivated the AFM option on the LT4 motors as found in the 2018 Camaro even though they do have the correct components in the engine.

 

[Skylarking]

@FPFQ_king that may all be true.

And if Holden didn’t have their heads up their but, the best of the last of the VFs would have had LT1 V8 rather than the much older LS3’s designs so our VFs would have then met pollution laws without bullish!t exemptions. Just my view.

But OP has LS3 V8, and in that context using economy and V8 together is an oxymoron. Meanwhile spending $20k on LT1 retrofit into VF to save fuel is, well, just a stupidly false economy.