Deception

iTrader: (1)

Im curious why they dont make performance camshafts for the 2nd gen GS. i have been looking around and i found camshafts for an is300. but i dont know if that makes a difference for the gs300

Lexizm

iTrader: (2)

From what I understand, no. There are maybe two places that I know about but they're not mass produced. It's a case by case basis. One is Lextreme and the other I forget, but they make custome pistons. I'll try and locate the name.

GS FONZy

iTrader: (6)

if it fits the IS than it should work fot the GS.
This is news to me, I didn't know there were cams for VVT heads.

Deception

iTrader: (1)

well i was browsing thru looking for performance parts and i had found like camshafts for is300 but i was thinking arent they the same engine.
http://www.vividracing.com/catalog/i...Path/4206_4504

mex lex

iTrader: (4)

Yes its the same as IS/GS. The Brian Crower cams listed on vivid racing site have not been released. Supposedly they have been on hold for years now and many IS owners don't think they will ever come out. According to some my.is members, BC says the long wait is due to a hold in materials. And yes they retain VVTi. Some prototype camshafts were made at LMS but were never released. I think gains were around 10 rwhp. Either way, I wouldn't mind buying a set, if they were available.

On a side note, I wouldn't mind having a BC 2JZ stroker kit. An estimated 80 rwhp gain .

Lexizm

iTrader: (2)

They are correct. If there is one one for the IS it would fit the GS3. Sorry I automatically started thinking about the 430. My bad.

kevs98GS4

iTrader: (1)

That's because V-8 is drilled in your head! I understand and do the same thing!

GS FONZy

iTrader: (6)

since we are on the subject of IS and GS3. Does anyone know why the IS is detuned to 215hp as compared to 225hp on the GS?
Maybe there is a timing diffrince and that maybe the reason these are only listed for the IS

TAMR_GUS98

If I remember right, the 2GS3 gets the extra 10hp because of a more free flow exhaust. The 2GS3 has dual exhaust.
-Will

GS FONZy

iTrader: (6)

are you sure
why is the LS4 and SC4 10hp less than the GS4? all three are dual exhaust.

JBrady

VVTi rotates the intake camshaft which either increases or decreases the overlap with the exhaust as well as how early the intake valve opens and how late it closes.

So, the problem is to increase the base timing of the cams would result in more overlap during those settings of the VVTi. These engines use the VVTi to create this overlap to achieve the EGR function and that is why there is no EGR on the 98+ model years with VVTi.

It would be difficult to choose any increase that would not create other problems. The best option would be for more valve lift but the heads would need to be worked (ported) properly as the stock ports go turbulant at slightly more than stock lift settings (IOW, flow goes down even though valve lift goes up).

There is no easy answer here so instead of cam changes I would recommend maximizing the ports and chamber. This would mean high velocity porting (small ports with optimized shapes) combined with a bump in compression ratio to maybe 11:1.

This would probably require running 93 octane fuel.

This would only make sense with headers such as S&S or possibly full length with true merge collectors (not emissions legal).

I really do not know what the maximum power potential the factory heads and cam design will support but 25hp is reasonable over and above the best effort with untouched parts. Personally, I am thinking the heads/cam probably restrict this engine to 375hp/300rwhp at stock RPM limits.

That said the mods can increase the mid range power and response which WILL make these cars progressively quicker/faster

If you race 2 cars that weigh the same, have the same gearing and the same peak horsepower/killowatts the one with the better mid range power will be faster in every case accept cars with CVT transmissions.

There are companies that will take a stock camshaft and make it bigger either by welding or grinding a smaller base circle (both have long term wear problems) and if someone could overcome the stock rev limiter, fix the flow to tolerate higher valve lifts and do the other suggestions we could see an engine that will increase power to 7000+rpm. All in all more work for less than supercharging or turbocharging.

TAMR_GUS98

Not sure about the LS4/SC4 to GS4 comparison. But if I remember right, they mentioned it to us when I was sent to Irvine for some Lexus certified training. I used to work for a Lexus Dealership here in NorCal.
-Will
Btw, have you ever compared the exhaust on an LS4/SC4/GS4, Manifolds all the way down?

GS FONZy

iTrader: (6)

I know many companies do the same thing, detuning, while using the same long block. I am willing to bet it is a sales marketing tool

BurgandyGS

HKS makes the camshafts and it comes with a vvt-i controller. fyi

NBart

In checking with the Tech's at the Lexus dealership where I work, his statement is absolutly correct. The reason there is increased HP for the GS over the LS and SC is due to the increased flow. The LS is designed to be a quiet/smooth riding car. If Lexus did not put noise surpression into the exhaust it would be too loud, and this causes it to loose HP. My understanding of the SC is that it runs a tighter stock exhaust then the GS. It si shorter and more conjested.