Title says it all. How high can these motors go safely with a built motor and a fully upgraded valvetrain?

 

7K safely, I would say 8.5 with a cam that can make use of it and all upgraded parts.

 

there is no "right" answer - it all depends on the components used, the budget/level of the build, and the person building it - without those figures, all you are going to get is a series of random #'s, non of which really means anything.

My setup (see signature) is currently set at an 8400 rpm redline, no issues at all

 

here is a fun video of my all motor setup, we actually took it to 8500 after this and had no issues. i seriously think that 9000 or over 9000 would not be out of the question.

http://performancefactory.com/videos/8grand.wmv



thats an all motor VQ35DE with valve train and dual valve springs. i will be doing another one here soon

 

what cam did you use?

 

i had some old S1 cams laying around the shop. we scrapped the project just to do some other things but we will be back. i think 350 whp on pump gas is very possible. a lot of things i would do differently.

 

Wow that all motor DE is sick!!

 

this company claims to have an engine package for the VQ35 that makes 500HP at 8250!

http://www.torukucams.com/page/page/4974904.htm

 

I don't think that is getting to the wheels.

 

so what! even if it makes 400 to the wheels, that's 100 whp more than anyone else has made on a naturally aspirated VQ35.

 

+1 we need to know more

 

So a website for a company that no one has heard of claims to have something that no one has seen and has yet to be proven...

uh huh...

The VQ platform makes 450hp+ n/a in it's Formula Renault configuration. It's very likely, really a given, a proper race engine builder could make one that produces the numbers they are claiming. Now is this one of those companies?? Doubtful but w/o knowing who they are and their qualifications, maybe.

 

thank you

 

JWT shims, springs are purported for use "above 7k" but a precise limit is not specified. With this kind of statement, my sense is that sticking to the lower part of the 7k range is prudent. I called JWT to ask about cams, springs, etc and could not get exactly a straight answer from Mr. Clark. He actually recommended not using their springs with the cams I had chosen (JWT S2). Was told it would not hurt but would slightly decrease hp due to added resistance to valve opening. FWIW.

I did end up installing their springs, shims, and S2 cams.

 

I have a complete Ferrea valvetrain including Ferrea oversized valves and JWT cams. I'm in the process of changing my set-up around and will be using larger turbos. I'd like to know what I could safely rev to as this will aid in turbo selection. If I can rev higher, i'll use slightly larger turbos and give a little low end up. If not, i'll stay a bit smaller and maintain some low end. Can anyone throw a guess out there? These motors to have a good Rod to Stroke ratio. 7500, 7600, 8000.....???

 

The simple answer: do the math or find a builder that can/has.
Realistically your rpm limit is going to be dictated by the ve of the engine. Once you get on a dyno and see where the power trails off. No point spinning if there are diminishing return. Remember it's all a trade off. The wear and tear increase as rpm limit is increased is not a linear function. It's alot closer to a 4-fold increase in stresses as rpm rises.

So can you spin your new motor to 8k, most likely yes. Will it make power there? Unknown. How long is it going to last? Well now that's the $64k dollar question.

Find a competent builder and pay for their expertise.

 

I was told the same thing by wolf when talking about stouter springs.

here's a rebuttal to that theory from Crane Cams:

Common Misconception:
Many people mistakenly think that using higher seat pressures causes a reduction in the horsepower delivered to the flywheel because higher seat pressures (and also higher spring rates required for high performance) require horsepower to compress the springs. This thinking is simply incomplete! For every valve that is opening and its valve spring being compressed, another valve is closing and its valve spring is expanding. This expansion returns the energy to the valve train and the engine. This results in a net power loss of "0" hp. Many engineering texts refer to this as the "regenerative characteristic" of the valve train. Recent tests at Crane have shown no horsepower loss on a hydraulic roller equipped engine when changing the seat pressure from 135# to 165#. Power actually improved significantly at top end, probably due to better control of the relatively heavy valves in the engine.

 

Did you find any pics to their carbon fiber upper inlet manifold and carbon fiber lower plenum...? Sounds interesting...

 

this is a good article and i agree with the logic but i dont agree that it applies to the vq,unlike a v-8 with one camshaft we have 4 over valve cams making the sharing of energy much more difficult for the vavle springs.you should always in either case use the lightest/softest spring to get the job done because they do not only effect rpm but the longevity of valves,seats and cams themselves.if jwt suggests softer springs for the power curve of that cam then they already have gone heavier and found diminishing returns.

 

no...I faven't found anything on them. I just happened upon the link to that page while googling VQ35 titanium valves.