Built 20v Rev Limit?

Zanek
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Built 20v Rev Limit?

Postby Zanek » Sun May 25, 2014 4:44 am

I'm currently in the process of building a 20v BT and I'm just curious as to some of you're opinions. What would some of you's recommend I safely rev my engine to? It will be for street use and I not overly fussed on making huge numbers on the dyno, just want the engine to be set at a reliable limit. Thakns

This is my specs list.

CP 81.50mm bore high compression forged pistions
C/R 12:5:1
Brian Crower H beam forged conrods
ARP head studs
Fidanza Adjustable Cam Gears
HKS timing belt
Kelford 194-C racing cams
Intake: 284' Duration 9.30mm Lift.
Exhaust: 278' Duration. 8.50mm Lift
Kelford Cams racing valve springs
Fully Reconditioned Block and Head
Port and Polish
New Water Pump
New Oil Pump. Ported and possibly High Pressure Kit.
TRD 0.8mm multi layer metal head gasket
1zze Coilpacks
All SamQ Engineering RWD Conversion Parts.
Koyo 53mm core Aluminium Radiator
Running off a Haltech Platinum Sport 1000.

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yoshimitsuspeed
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Re: Built 20v Rev Limit?

Postby yoshimitsuspeed » Sun May 25, 2014 8:54 am

Your build seems contradictory to your goals.
For a reliable limit I would leave it at the stock redline. RPMs take their toll on motors over time.
Those cams on the other hand will just be waking up around stock redline.
To really let them breath I think they would still be going pretty strong around 9k to 10k.
Most reports I have heard from those I would trust have said the stock bottom end can handle 9k-9500 without modifying the block or internals. More than that and you would want to brace the block and may need to consider an aftermarket crank.
So really you could put your redline somewhere in that range but you have to ask yourself how much time you will spend there and how much you want to sacrifice longevity for a little extra up top.

For your goals I probably would have gone with the 194-B and planned for sticking around the stock redline.

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oldeskewltoy
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Re: Built 20v Rev Limit?

Postby oldeskewltoy » Sun May 25, 2014 8:56 am

Not being up on 20V parts... does Fidanza make 20V cam pulleys??

I'd say peak power will be about 9000, the stock oil pump limit is about 9k-9.5k(look into the Toda gears for a bit more comfort zone) .... as long as its assembled correctly... I'd say your good to go.

It will be for street use and I not overly fussed on making huge numbers on the dyno, just want the engine to be set at a reliable limit. Thakns


BRAINFART.... **IF** the chambers are "detonation safe"... and since the cams can twist to 9k... I might try and maximize the tune from 2000-5000 to improve street manners... You'd need a dyno to get this right....


OR as yoshi points out... a slightly milder cam
OST Cyl head porting, - viewtopic.php?f=22&t=300

Building a great engine takes knowing the end... before you begin :ugeek:

Enjoy Life... its the only one you get!

Zanek
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Re: Built 20v Rev Limit?

Postby Zanek » Sun May 25, 2014 2:51 pm

I definitely appreciate the words of advise, still have a lot to learn when it comes to building engines. I'd say I'm going to go with the Toda gears and go to 9000rpm mark. Yes Fidanza definitely do make them. :)

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yoshimitsuspeed
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Re: Built 20v Rev Limit?

Postby yoshimitsuspeed » Sun May 25, 2014 7:40 pm

If at all possible I would try to keep the VVT to spread out your power band as much as possible.

I believe I have figured out a way to reclock the VVT gear so as to be able to change cam timing but I still have a lot of R&D to do on that.
If this is possible what you would want to do is dyno or street dyno it with a variable cam pulley then when you found the cam timing that you liked best I could try to clock a VVT pulley as close to that as possible.

I can also get Toda gears or anything else you may still need for your build.
I may be interested in your pulley if you decide to go dual adjustable.

Jimmee1990
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Re: Built 20v Rev Limit?

Postby Jimmee1990 » Sat May 31, 2014 6:59 pm

To do 9000+ rpm safely, I would look into getting the crank lightened and balanced pretty finely also if you're going to use the standard Toyota crank. I would also make sure whoever is building the engine pays very close attention to bearing clearances, as they are critical at those revs. I have had good results with using .0012" clearance on the big ends and mains, the next engine will be at .001" on both. Your pistons and rods will be good to higher RPM than that again, so I would say like the others that you're only real weakness would be the oil pump gears. You may want to look into something to brace or replace the main caps also, as they are known to flex and occasionally crack with sustained high revs.

High RPM will wear everything exponentially faster, however if you're not doing those revs all the time it will still last a very long time.

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oldeskewltoy
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Re: Built 20v Rev Limit?

Postby oldeskewltoy » Sun Jun 01, 2014 11:50 am

Jimmee1990 wrote:To do 9000+ rpm safely,

You may want to look into something to brace or replace the main caps also, as they are known to flex and occasionally crack with sustained high revs.

High RPM will wear everything exponentially faster, however if you're not doing those revs all the time it will still last a very long time.



In particular #2 and #4

Image
OST Cyl head porting, - viewtopic.php?f=22&t=300

Building a great engine takes knowing the end... before you begin :ugeek:

Enjoy Life... its the only one you get!

Zanek
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Joined: Tue May 20, 2014 7:29 am
Location: Australia. Gold Coast

Re: Built 20v Rev Limit?

Postby Zanek » Mon Jun 02, 2014 7:01 pm

I think I'm just going to stay around the 8000-8500 mark and get smaller cams if need be, thanks for the advise guys.

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