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  • The MR2 Australia SW20 (p.30)
2014/05/18 17:58:27
B24
I disagree. Yes there are two people who have used the standard valves to produce great horsepower figures but there is more to it than just a big horsepower figure for car which spend a lot of there time being flogged every time they are started.
What are saying is every racecar should change to OEM valves as these are better? I changed by recommendation from someone who has building race engines for endurance racing/rally blah blah blah for 30 years. If OEM was the correct valves, everyone would be using these. They are not as OEM will fail long before a good quality valve which is specifically made for an operating range outside of street applications.
The same goes for valve sizing. Even if there is a minimal gain, it is still a gain but most important is you can run less boost, less heat, less stress, better spooling which is critical in circuit racing.  
I do not understand how this is even being debated?  
 
2014/05/18 18:35:26
Admin
+1
2014/05/18 19:02:14
MCT_MR2
B24
I disagree. Yes there are two people who have used the standard valves to produce great horsepower figures but there is more to it than just a big horsepower figure for car which spend a lot of there time being flogged every time they are started.
What are saying is every racecar should change to OEM valves as these are better? I changed by recommendation from someone who has building race engines for endurance racing/rally blah blah blah for 30 years. If OEM was the correct valves, everyone would be using these. They are not as OEM will fail long before a good quality valve which is specifically made for an operating range outside of street applications.
The same goes for valve sizing. Even if there is a minimal gain, it is still a gain but most important is you can run less boost, less heat, less stress, better spooling which is critical in circuit racing.  
I do not understand how this is even being debated?  
 




I will start by agreeing 100% that changing valves to that of suitable materials for prolonged heat generated in motorsport use, where OE valves will not cope and burn out more frequently.
 
As for the use of oversized valves in a multi valve engine for sprint racing, like you both compete in i will diagree massively. removing material, for a larger valve, therefore putting valve seats closer together which leaves less of a heatsoak area for the valve to transfer heat to the head does not make sense. In a drag race motor, where every last hp is needed for a short burst, sure there is a gain. In a time attack engine where you will do 2 hot laps tops with a cooldown in between, and really need an engine to survive 5 minutes flat out, yes an oversize valve makes sense when a budget allows. In an older design 2 valve per cylinder engine where there is still ample material left in the head to allow adequate quenching of valve temps, yes and justifiable for the gains. In an engine doing lap after lap?? where temps get really hot, and stress components unbelievably?? Not unless you have the play money and are going for every last tenth to win a championship. Your priority is on reliability, so an expensive exercise for a tiny gain, does not make a value or sound choice.
 
Don't get me wrong, if that is the recommendation your engine builder has given you, if i was in your position, i would have also followed it. In the case of the engine builders i have dealt with, running oversized valves is one of the last things they would recommend, particularily in the application both bud and yourself use them for.
2014/05/18 19:13:24
Admin
Maybe so, though less boost also means less heat anyway.
2014/05/18 19:14:15
kameleon
1mm + valves just because?

Why arnt we running endless valve lift too?

Why are we only running 2.2l and not 2.4l?

Probably because there is a reason to change some things and leave others alone.....

Agree with the above ^
2014/05/18 19:22:08
Admin
Other than the ****ty alloy that Ferrea use, has anyone else had an issue with 1mm oversized valves in a 3SGTE head? No.
Will a 1mm larger valve improve performance. Yes.
I completely rebuilt my head and wanted new valves so why not buy oversized ones if they improve power, even if by a small amount?
I really don't see what the problem is. I had bad luck with Ferrea. So what? I'm still glad I went to 1mm oversized.
I got the result I was after with my current build - same power with 5psi less boost. Surely that will be a lot less stress on the engine????
Here's a different angle -
  1. With all my previous engines, I had standard valves and was never able to run more than 2 track days in a row without issues
  2. Since using 1mm oversized valves I have run 4 days without issue. The car is only broken now because of the bad Ferrea valves, not because they are 1mm oversized
OK guys here is a challenge. If any of you with a 3SGTE with standard valves can get a better lap time than me in the next MTC, I will buy you a case of beer. It will be a stock valve vs. 1mm oversized valve challenge! :-)
2014/05/18 19:29:59
kameleon
Without a back to back change of only the valve size we wont know.....

Bigger isnt always better.

2.2l should be making far more power than you are right?
2014/05/18 19:52:06
Admin
The CT26 is holding me back. I expect 300kW after a turbo and manifold upgrade running 25psi
If I can keep it reliable at that power it will be a VERY fast car
2014/05/19 12:16:05
MR2QIK
Steve, do you know anyone that's had standard valves fail? Street car or race car? Standard valve equiped, modified 3SGTE's have participated in various forms of motorsport around the world & to my knowledge, valves have not proven to be a weakness. My motor's spun on numerous occassions to near 9000rpm. It's not a racecar, but has seen rpm that not many here have.
 
I'm not a fan of change for the sake of change. I agree that if done right (ie not dodgy ferrea's), no harm in 1mm oversize & a small power gain. If anyone here takes apart their head, fits 1mm oversize valves & makes an additional 7rwkw (10 odd hp - equivalent to traditional 1psi gain) with no other changes (timing advance, boost, AFR etc), I'll buy you a case of beer.
 
In no way, shape or form did I recommend anyone or Bud revert back. Simply stating for any readers that the small gain may not be worth the hassle/risk.
2014/05/19 12:29:08
B24
Don't get a big turbo for big power. When I ran mine with the GTX3071r, it was too laggy off the corner. Way too much. I drove Pat's car with a stock set up and it was far better off the corners. My original engine/turbo was also far better off the corners than the 3071 set up. The 3071 was fantastic when on boost, but at a short circuit it really was not a advantage. If you change, get something where you are not loosing any lag or you will be disappointed.
If my car can do a 1.08.1 with 175rwkw(about) you should be doing the same with 200rwkw and current weight of your car. In-fact, my car was capable of a lot quicker if the set up was right so don't go crazy with chasing big power. Put water to air intercooling and Spax custom coilovers before wasting money on a turbo conversion. The go on a diet ya fat bastad.
Looks like plenty of debate on the valve sizing. Point being, the increase has worked for you and that's what important.
MCT, mine is built for the 300km endurance races but the 3SGTE is not the right choice hence the 2GR conversion. When we ran the 3SGTE for the 2013 race, the tune/turbo/coil on plug let us down. Valves were fine but its very hard to make a statement when we could not compare any previous data. Hope you can make the 2015 event. Would be great to have a chat.
 
 
 
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