Cam advice

[Spid]

I have a mast motorsport LS7 I have now done 5000 miles, trip to Milau bridge and track day at Spa.
I'm very pleased with the performance but it is very lumpy under 2000 rpm which makes driving in traffic unpleasant, also it has very little manifold vac at idle so the servo I fitted to the clutch dosen't work very well.
Over the winter I want to change the cam, should I go for a standard cam? Or are there other performance ones that don't cause these problems

[F.C.]

Have you put it on a rolling road and fine tuned the fuelling and ignition at the bottom end?

I have a supercharged LS3 that was reasonable unless you hit stop start traffic,
then it was rough and a real pain to keep rolling along.
A couple of hours on a dyno with a couple of fuel injection egg heads had the Idle smooth and transition is seamless .
Crawling along in first gear on tick over is no longer a drama at all.

[harry b]

Totally agree with F.C.
Had the same problem when I got my Caterham. Different car, different engine, but about same power to weight ratio and very long first gear.
It has a 308 degree cam with a powerband ranging from 3000-8500rpm with peak at 8200. Not the type of cam you'd expect to be civilized in combination with throttle bodies.

Did a lot of tweaking on the rolling road, and now behaves like a hybrid in traffic. Can troddle along in any gear at around 1000rpm.

Major tweaking was done on the ignition timing to get it right.

[deadscoob]

Who did your mapping FC, were they down South?

[F.C.]

deadscoob said:

Who did your mapping FC, were they down South?

I Got Trevor Jasper (yellowshed) of mountune / Roush/Revolve (well known Noble mapping Guru) down to Track and Road in Rainham Essex where there are two guys called steve, Both of whom are also extremely knowledgable chaps.
between them they actually dumped the original map and completely re-mapped it.
My fuel economy has got noticeably better, something like 5-6 mpg (broke my foot so haven't done enough mileage to get an exact figure).
Their dyno figures have been proven correct time and time again.

http://www.tracknroad.com/

[Spid]

deadscoob said:

Who did your mapping FC, were they down South?

Was mapped by AFR made it better than it was. They are not a LS specialist so might be worth giving someone else a go before I pull the engine out.

[Spid]

There is a company near Bedford isn't there who specialise in LS engines can't remember the name

[Graham-P]

Monkfish, they are on the HSV&Monaro forum, I think the guys name is Roger, linky here

[Spid]

Ls power was who I was thinking of, have a pic of an Ultima on their site, any one used them

[ultimass]

I have the same problem with my LS7 running a Motec ecu.

Have tried to smooth out the power delivery under 2000 rpm but no success.

I have been told it is due to the hi performance cam fitted (the engine puts out 700bhp)

Now looking at fitting a milder cam bringing the power down to about 600bhp but also having far more pleasent road manners.

Kyle (GulfLS3) has been researching one.

Martin.

[Spid]

I'll give him a ring

[738 driver]

He will have one for you within 24hrs Martin.

[HairbearTE]

For those who haven't seen or heard a MAST motorsports LS7, here is their 675hp version "ticking over" in the back of a 911(!)...

http://www.youtube.com/watch?v=NBF5HcXsiI4

Personally I think this is one of the best sounding engines ever, it seems to be idling ok but I can see how it might be a little painful in traffic!

[Spid]

Yep that's the one made 600 bhp over here. If you go to the Spa vid post and click next you can see the engine in place and the dyno