exhaust cams and porting for power
01-20-02, 04:19 AM
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exhaust cams and porting for power
I am reading a book called "21st Century Performance" by Julian Edgar at the moment.
You can buy it from the www.autospeed.com site in the shop.
Anyway there are two particular chapters with very interesting information on the 1UZ-FE V8.
The first chapter "Engine and Driveline" part "camshafts" has a whole section about the 1UZ-FE camshafts and how they compare to other high performance engines. Standard specs are listed and they model changes (using Dyno2000 software) to the cams and resulting horspower increases.
The most effective would seem to be changing the standard exhaust cam for an exhaust cam with revised opening of 55 degrees BBDC (Before Bottom Dead Centre) and closing of 18 ATDC (After Top Dead Centre) (standard exhaust is 46 BBDC and 3 ATDC). This changed exhaust cam with the standard intake increased the horsepower from 260 to 300 !! (modelled on Dyno2000).
Although changing the exhaust cam (getting it welded and reground?) doesn't sound like a simple job.
The second very interesting bit is head porting. A 1UZ-FE head is flowbenched before and afterward being ported. Increases in flow on the bench usually relate directly to horsepower increases. After porting the intake flow increased by 19 percent and the exhaust by 14 percent!!! These are actual flow bench figures. Not only that but there are 12 full colour photos of before and after closeups of all the critical parts to pay attention to when porting. An extimated 20 hours was spent porting both heads.
I haven't heard of anyone ever trying different cams (only a supercharged 1UZ-FE, Ivan Tighe did those) or porting the heads for a street car -
Anyone heard anything or given it a go?
You can buy it from the www.autospeed.com site in the shop.
Anyway there are two particular chapters with very interesting information on the 1UZ-FE V8.
The first chapter "Engine and Driveline" part "camshafts" has a whole section about the 1UZ-FE camshafts and how they compare to other high performance engines. Standard specs are listed and they model changes (using Dyno2000 software) to the cams and resulting horspower increases.
The most effective would seem to be changing the standard exhaust cam for an exhaust cam with revised opening of 55 degrees BBDC (Before Bottom Dead Centre) and closing of 18 ATDC (After Top Dead Centre) (standard exhaust is 46 BBDC and 3 ATDC). This changed exhaust cam with the standard intake increased the horsepower from 260 to 300 !! (modelled on Dyno2000).
Although changing the exhaust cam (getting it welded and reground?) doesn't sound like a simple job.
The second very interesting bit is head porting. A 1UZ-FE head is flowbenched before and afterward being ported. Increases in flow on the bench usually relate directly to horsepower increases. After porting the intake flow increased by 19 percent and the exhaust by 14 percent!!! These are actual flow bench figures. Not only that but there are 12 full colour photos of before and after closeups of all the critical parts to pay attention to when porting. An extimated 20 hours was spent porting both heads.
I haven't heard of anyone ever trying different cams (only a supercharged 1UZ-FE, Ivan Tighe did those) or porting the heads for a street car -
Anyone heard anything or given it a go?
01-20-02, 03:08 PM
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"The most effective would seem to be changing the standard exhaust cam for an exhaust cam with revised opening of 55 degrees BBDC (Before Bottom Dead Centre) and closing of 18 ATDC (After Top Dead Centre) (standard exhaust is 46 BBDC and 3 ATDC). This changed exhaust cam with the standard intake increased the horsepower from 260 to 300 !! (modelled on Dyno2000). "
Doesnt surprise me at all. I believe the VVT-i 1UZ-FE's had their cam shaft timing, etc revised and they are at about the same pwr lvls.
"Although changing the exhaust cam (getting it welded and reground?) doesn't sound like a simple job. "
If we can get camshaft blanks then it should be easier to find a shop willing to grind them.
"The second very interesting bit is head porting. A 1UZ-FE head is flowbenched before and afterward being ported. Increases in flow on the bench usually relate directly to horsepower increases. After porting the intake flow increased by 19 percent and the exhaust by 14 percent!!! These are actual flow bench figures. Not only that but there are 12 full colour photos of before and after closeups of all the critical parts to pay attention to when porting. An extimated 20 hours was spent porting both heads. "
Seems like we would see huge gains in performance like the LS1 guys from heads and cams.
Doesnt surprise me at all. I believe the VVT-i 1UZ-FE's had their cam shaft timing, etc revised and they are at about the same pwr lvls.
"Although changing the exhaust cam (getting it welded and reground?) doesn't sound like a simple job. "
If we can get camshaft blanks then it should be easier to find a shop willing to grind them.
"The second very interesting bit is head porting. A 1UZ-FE head is flowbenched before and afterward being ported. Increases in flow on the bench usually relate directly to horsepower increases. After porting the intake flow increased by 19 percent and the exhaust by 14 percent!!! These are actual flow bench figures. Not only that but there are 12 full colour photos of before and after closeups of all the critical parts to pay attention to when porting. An extimated 20 hours was spent porting both heads. "
Seems like we would see huge gains in performance like the LS1 guys from heads and cams.
03-15-02, 08:06 AM
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My exhaust cams were finished today ! -Should get them back early next week, then another week to see if it was worth it. Read the story so far on my site
03-15-02, 09:16 AM
#4
Lexus Champion
Peter, didn't know you were having it done, looking forward to hearing the results from you. Ivan Tighe did the cams on the Powerhouse Soarer, right? Are you familiar at all with this gentleman Greg Gower that did the headwork for them? If the dyno software and flowbench are right, there's lots of potential here, which we all suspected, we just need guys like you to go ahead and start the trial and error, let us know as soon as it's all buttoned up, and have Natasha take some video of you burning the belts off your tyres.
Cheers -
Jon
Cheers -
Jon
04-06-02, 09:05 PM
#7
Lexus Champion
Peter, less us know when the shims are done. By the way, lost that pic of your adjustable rear headrests, mind posting it again? Thanks from your Yankee ******,
- Jon
- Jon
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