LS 3 Upgrade and Installation

[rs_man]

Hi All, I have decided to take the plunge and swap existing sbc for a nice shiny LS. I have decided to go with the 3 instead of 7 for cost reasons. I know the 7 is supposed to be a much better option, but twice as good?

I have a few questions that hopefully some of you can answer:

1. What is the best cam to fit, I have read about the GM Power upgrade cam that adds 50bhp bringing it to 480. Is there a better cam to fit, not to worried about slightly lumpy idle, I want an engine that has some character :-) but still drivable around town when required.

2. Headers, I was thinking about using standard headers to keep costs down, I know that they are not going to be as good as the Ultima or other options but a much cheaper option and still neat. As my car has already got V5 with visual inspection pnly duee to the old lump fitted I assume I wouldn't need to fit cats?

3. I currently have a G50-21 6 speed out of a 993. Will I need to fit new adaptor plate or can I modify to fit new engine. Also do I need to change flywheel, clutch cover and plate?


Regarding fuel supply, has anyone investigated the option of fitting in tank swirl and high pressure pump into say left hand side tank and using other tank to fill it up with just the balance pipe?

Thanks in advance for your help.

PS I live in North Shropshire near Whitchurch. Anyone fancy helping out with a bit of spannering :-)

[AndreasW]

Concerning the headers:
I am running into the same question as I am going to install my LS within the coming next weeks.
(However, I need catalysts and this puts an additional (space-)problem on it.)

Wouldn't JBA Shorty Headers be an option?
They are compact not that expensive and offer a moderate hp gain over the stock ls headers.

Here is a pic of a set for the 04-06 GTO (LS2 engine):
http://www.jbaheaders.com/assets/images/products/h...

[Mjpmark]

Please Please DO NOT buy the 480 cam upgrade.

I did and have had the expense of swapping cams etc. There is a hug thread re this a few months back.

[rs_man]

Tell me more. I guessed it may not be the best option, found this interesting link

http://www.carcraft.com/techarticles/ccrp_1010_ls3...

LS3 can certainly manke some reliable power.

Regarding ECU's is it best to stick with GM factory one with fly by wire or go for one of the aftermarket ones such as FAST, Holley.

Cheers Tony

[Graham-P]

Here's my LS3 exhuast set up with standard headers, no cats. I have the GM ECU and flybywire throttle, no problems.
Thread is here on my install.
http://www.pistonheads.com/gassing/topic.asp?h=0&a... Engine Install.........&mid=27835



Graham

[Gulf LS3]

Hi Tony

As Mark says do not fit the 480 LS3, the cam is awful and does not work well, i have used a custom cam for the LS3 which has given 545 bhp on Tim Adams dyno. To work at its optimum you should really replace the pushrods, lifters and springs.

The headers are very important as proved also on the dyno, the 3 needs a little help on the exhaust side and thus the headers are key, you can use the stock LS headers but it will blunt the point of fitting the big cam, if you go with the big cam the headers need to flow better than the GM cast units for you to see the benefit.

Run the GM ecu its great on fairly standard LS engines and then you can run the great fly by wire throttle, you will never achieve great MPG figures on an aftermarket ECU and it will cost you a lot more money going aftermarket for no return imo!!

The 3 will give you 90% of the 7's performance for half the cost as you say a no brainer. You will need a new flywheel and possibly adaptor but it may be able to re use your clutch and starter depending on a few factors.

It would be possible to set the fuel system up as you say but you will need a larger link pipe than fitted to the standard tanks ie dash 6, i would suggest a 10 as a minimum.

[738 driver]

......and there's more..

[ROWDYRENAULT]

RS MAN The JBA headers will not fit, been there done that. Hope that helps, lee

[rs_man]

Thanks for the info Lee, cheers Tony