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MMR billet secondary tensioner

8K views 20 replies 9 participants last post by  yan88gt 
#1 ·
#3 ·
dude its to correct the problem with the passenger tensioner changing the cam timing. I guess you didnt read the thread.
 
#4 ·
They claim that the cam timing can be off by up to 7 degrees on the passenger side due to the tensioner being on the wrong side of the upper chain. The chain that connects the two cams together. Then they also claim that the power increase from correcting this design flaw will take the variance on the timing down to about 1 degree or less and gain 4-5 MPH in the 1/4? If that is true then why did it take so long for anyone to communicate this information? They are talking quite a bit of power there.
 
#13 ·
From what I understand, the factory setup let's your timing dance around up to 7* on the cams on that bank. Keeping the tension on the correct side of the chain stabilizes the cam timing. I believe the 5-6mph came from the additional 5# of boost his car picked up from the corrected timing. Maybe I'm wrong, but that's what I gathered...
 
#16 ·
Here is what I know about the tensioner and chain setup:

-Testing was performed on a Pro Mod twin turbo arrangement
-It brought the car from 228 to 232 mph
-Went from 6.30s to 6.18 in the 1/4
-Went from 52psi to 55psi
-Engine dyno testing would like to be performed on N/A and twin screw combinations

4 mph and >0.1 in the quarter is nothing to sneeze at for that power level. If you open Mark Olsen's cam chart, populate it with numbers, and throw around 7 degrees, you will get a good visual on what 7 degrees will get you. The kit definitely illustrates the potential of 4V cam timing on any combo.

Now...are you losing 7 degrees at your power level? Is secondary bank cam timing loss magnified at 2000+ HP? How will N/A and supercharged combos respond? I think it is very well proven for the high-powered twin turbo arrangements. If I had one, I would definitely consider the kit without any further testing results.
 
#18 ·
I would like to see what this mod does to an almost stock set up. It is a lot easier to engineer predictions about what it will do with different set ups if you start from the beginning, rather than trying to reverse engineer it off of a mega turbo set up. Something to remember about the testing on the 2000 HP turbo car is that turbo performance goes up with exhaust gas energy. If the timing issue was causing the exhaust gas energy to be less coming out of one side of the motor then this could have a significantly amplified effect on a large turbo car and how well the turbo spools. It might not be as drastic on a N/A or supercharged application. I am sure that someone will try it soon enough and let us know.
 
#19 ·
Another excellent point. Not only will the chain slack less on an 800hp blown car, but the gains from improved exhaust valve timing would be less than for a big turbo application.

Chances are the threads we see by people that try this mod will have irrelevant data because they change cams, boost, swap to auto, or change power adders at the same time...
 
#20 ·
This mod isn't advertised for stock-like combinations fellas. MMR states "up to 7 degrees" and "high HP" combinations. This mod is for people running a lot of power.
 
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