Titanium valves - How much HP ?
Discussion
Valves in a pushrod engine only approximately follow the cam at 7600 rpm. Lighterwight valves means lighterweight valve springs which means it has a chance of following the cam better and opening and closing when it ought to. This would push the power peak up the rev band I would have thought.
Don't titanium valves have much narrower valve stems? That's got to be where most of the extra power comes from.
Of course running in the engine and putting it on Mobile 1 since it was last on the AS dyno has to account for something too!
Don't titanium valves have much narrower valve stems? That's got to be where most of the extra power comes from.
Of course running in the engine and putting it on Mobile 1 since it was last on the AS dyno has to account for something too!
canam-phil said:
My guess is that unless the valve train was limiting the max revs and the hp curve was still on the up at the old max revs, then the titanium valves would have marginal bhp effect. Gman, did you ever say what revs the max bhp was developed at?
So I am theorising that the torque/hp curves are very much the same up the rev range. May be very marginal changes due to valve flow but more down to atmospheric test differences that are compensated out by the calibration factor.
Gman, are you going to publish both dyno charts for us all to look at?
Phil
Starting to get there, I will publish them....
No I did not say where max power was made at just the max rev 7600 did not change
Boosted LS1 said:
G Man,
We need to know if the seats are unchanged and the valve angles the sameApples to apples and all that.
Also tell us if the stems are waisted or if the valves have different profiles behind the heads. Oh, are they sodium exhausts and hollowed inlets
Ah, I get it. You've done a 4 valve head
Boosted.
Boosted, this is true apples for apples, this is why it is so interesting.. Just the valves were changed ( lighter springs of course )
G Man
gdr said:
651 hp. Did they dyno engine just before the new valves fitted just to see what difference titanium makes? Otherwise most of any power hike might be due to effect of some careful and light running in that this motor has been subjected to over the last few months.
gdr
Sorry I only have the previous dyno, the tolerance on the engines were the same
Gareth
davefiddes said:
Valves in a pushrod engine only approximately follow the cam at 7600 rpm. Lighterwight valves means lighterweight valve springs which means it has a chance of following the cam better and opening and closing when it ought to. This would push the power peak up the rev band I would have thought.
Don't titanium valves have much narrower valve stems? That's got to be where most of the extra power comes from.
Of course running in the engine and putting it on Mobile 1 since it was last on the AS dyno has to account for something too!
If the valves have narrower stems then it would need smaller diameter guides, but they won't have been changed.
My guess would be the bhp would remain the same.
is 676HP.....but I think the running in had a role in the gains. We have a winner .....
685.6 BHP @6800 rpm That rounds up to 686BHP eclipsar you are the winner ....
I am rather shocked that I gained 45 bhp, remember the engine has done 6000 miles previously.
Why - you guys have come up with very good reasons
Valve stem size - maybe I don't know the difference yet i will ask AS
Heavier valve train must take energy
Davefiddle "Valves in a pushrod engine only approximately follow the cam at 7600 rpm. Lighterwight valves means lighterweight valve springs which means it has a chance of following the cam better and opening and closing when it ought to. This would push the power peak up the rev band I would have thought." - I found this very interesting as the power is up all the way along th rev range
Surely this does makes Ti valves a good power/cost option
G MAN
685.6 BHP @6800 rpm That rounds up to 686BHP eclipsar you are the winner ....
I am rather shocked that I gained 45 bhp, remember the engine has done 6000 miles previously.
Why - you guys have come up with very good reasons
Valve stem size - maybe I don't know the difference yet i will ask AS
Heavier valve train must take energy
Davefiddle "Valves in a pushrod engine only approximately follow the cam at 7600 rpm. Lighterwight valves means lighterweight valve springs which means it has a chance of following the cam better and opening and closing when it ought to. This would push the power peak up the rev band I would have thought." - I found this very interesting as the power is up all the way along th rev range
Surely this does makes Ti valves a good power/cost option
G MAN
Good power gain there!
I wonder how much of that gain was due to better ring seal and lower friction loss in bearings etc etc. Pity AS did not dyno BEFORE Ti valve change. That really would have given the true power gain - if all other things stayed the same ... but they never do!
When are you putting up the dyno results? I'm intrigued to see the curves.
I wonder how much of that gain was due to better ring seal and lower friction loss in bearings etc etc. Pity AS did not dyno BEFORE Ti valve change. That really would have given the true power gain - if all other things stayed the same ... but they never do!
When are you putting up the dyno results? I'm intrigued to see the curves.
[url] http://community.webshots.com/photo/233850284/233855104KcyjkN [/url]
>> Edited by G Man on Saturday 18th December 20:51
>> Edited by G Man on Saturday 18th December 20:51
G Man said:
Phil
I did a graph
http://image34.webshots.com/34/0/18/47/234101847XruZCR_fs.jpg
Maybe not ?? Need permision.... to enter link..
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