Do they make camshafts for 2nd gen GS
#1
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Do they make camshafts for 2nd gen GS
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
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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
http://www.vividracing.com/catalog/i...Path/4206_4504
#5
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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
http://www.vividracing.com/catalog/i...Path/4206_4504
On a side note, I wouldn't mind having a BC 2JZ stroker kit. An estimated 80 rwhp gain .
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#9
Lexus Champion
-Will
#11
Lexus Champion
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.
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.
#12
Lexus Champion
-Will
Btw, have you ever compared the exhaust on an LS4/SC4/GS4, Manifolds all the way down?
Last edited by TAMR_GUS98; 11-01-07 at 08:30 PM.
#15
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.