Hi,

Seeking any views or experience with uprated valve springs for my R56 cooper S, forged build.

We are sticking with current standard cam which we rev to 7,000rpm so far but at some point we may be running up to 45psi through our dual turbo setup and due to the reduced back pressure expect to be making power right to the top end of the 7,000 rpm.

As usual there is quite a lot of options available but not many people with experience to give guidance. Appreciate any input whatsoever.

I see Supertech do single beehive springs which are uprated to a point. What I don't know is by how much as the standard seat pressure for standard valve springs isn't easy to find (yet?).

Thanks :-)
Steven_RW

 

I can't help with your basic question, but want to offer advice on high boost. I'm running the Supertech beehives and have a 7K RPM limit, but seldom get that high. I requested 7.5K with my Manic tune but Nick saw fit to not provide it. Beehives are rated at what, 9.5K?

Another thought, my beehive springs were installed by Thumper when he did my last head work. Maybe he could help with your question. He was banned from this site but he might respond to email. Try his site contact info --- http://www.thumperheads.com/contact

Anyhow, there's a lot of plumbing between the turbo output and intake manifold. Lotsa angles, diameter changes, and functional modules --- each one requiring a connection of some sort, usually a hose clamp. Even at my 30PSI max, I have grief keeping the clamps tight --- engine torque, movement, vibration. and hoses "settling in under clamp pressure", all contribute to "manifold pressure" leaks as determined by the ECU. Yes, Manic and possibly other tuners can override map sensor limits, but when you get a leak at 45PSI, the ECU compensation (or learning) might introduce hazardous operation. I've already experienced this, before the Manic tune, and got enough super knock to break a spark plug.

So, plan for the best performance you want, but don't overlook the basics, i.e., tight and secure plumbing. Best of luck ---

 

I don't own a S but I do know that a place I believe in the UK is called 1320MINI, and theres another place in Europe called MINIGarage I believe. The guy from MINIGarage has his Cooper S somewhere over 400hp.

 

Both have extremely powerful minis, but be careful when comparing numbers --- in the USA, we usually get Wheel HP and ft/lb numbers, while the UK uses Brake HP and Nm numbers. In this range, BHP is typically 40 - 60 higher than WHP. There are conversion factors, but I don't try to remember them.

 

Yeah, it just came to mind when talking about this topic. Thought it might help!

 

Hi,

Thanks for all responses.

Beehive springs - Do you have a view on why you think the supertech beehive springs are good for 9,500rpm? My car saw 7,000 rpm all the time before this re-build, so I can't see why it won't after the rebuild. Personally I do like the look of those springs, just not really based on any data, other than gutfeel.

Boost Pressure - yep, I agree, once you get up to high pressures your entire system is running more pressure than in the air that keeps your tyres inflated. We will get proper control over this with hard pipes and good connections. The initial rebuild will just run my current turbo for a couple of thousand miles, so we have time to get on top of it. We may change the inlet manifold as well. It will be a steady progressing project. I also am starting to accept that we will need to move to Motec.

UK power figures vs American... interesting subject. Most UK rolling roads do a "shootout" mode where the car accelerates against a constant load for about 5 seconds. The rolling road then tries to guess what "power loss" there was to the engine. Personally we see those as crap.

When I watch American dyno shootouts, whilst they do give the power figure that they believe is at the wheels rather than try and guess back to the engine, the whole process looks the same as most UK rolling roads and at high horsepower looks a bit out of control and the whole test is over in a few seconds. If there is ANY wheelspin and it can be very hard to perceive wheelspin, the risk is the software thinks the rollers are being accelerated faster than they actually are and over estimate the power.

How we do it here is a constant state loaded rolling road and we measure the torque that the retarder is applying to hold the car at a set RPM. So A rolling road test takes quite a few minutes as the car is held at 1,000 rpm at WOT and a load is applied by the rollers to stop the car accelerating. Whatever load that is, is the torque and bhp is just caclulated in the standard way. This repeats all the way up through 500 rpm increments, allowing a big of time between applications of WOT to allow cooling temps to get under control.

This isn't the norm over here in the UK, but it seems to be the way to get a REAL braked horse power wheel reading that isn't bullcrap. It also gives time for proper analysis of faults as you are holding a steady rpm and can create an exact circumstance. This also gives me confidence that my car will survive a proper runway long distance top speed event as we hold it at that same peak RPM on the rolling road and check for detonation. My last top speed car was held for 45 seconds on the rolling road at peak power peak rpm before it's runway test to make sure it would not det. I don't believe you can compare a 3-5 second application of WOT on a shootout mode dyno to a real, NAIL the throttle and don't lift till the last second on a runway.

Last thing is also to compare wheel figures based on rpm of the roller. The faster the rollers are going, the more drag they create that the retarder doesn't need to create to hold the car at set rpm meaning the figure for the car is seen as lower. All quite interesting stuff. The main point is the rolling road needs to do what you want. 1 - provide a repeatable power figure for analysis of mods. 2 - be able to re-create a scenario to allow fault analysis. 3 - give you confidence your car will not det at the end of a top speed test.

Just thought I would share some views. Always appreciate the input gents.

Cheers,
Steven_RW

 

I'm going down the road of building a intake manifold. Have the stock manifold at an engineering firm and doing rough designs now .
I wonder if the stock mani could stay together with 45 psi , I think this might require a test with some block off plates and shop air compressor. Be sure and video it so if it does pop we can all get a good laugh out of it. .. Lol

 

Sure will.

What are you thinking with your design? Exactly same shape as standard but alloy or something different? What made you want a non standard one?

Ps I've ordered the supertech beehives and titanium retainers. Thx

 

I feel like there is power in the intake design alone. It's not very efficient in flowing as you can tell by the carbon build up favoring the drivers side. The throttle plate opening needs to move , the angle the blade just aids and packing air to the back 90 before it turns up the the plenum . There is a little divider in the plenum that is suppose to help split the flow between 2&3 cylinder but all the air coming in is favoring to the 3&4 cylinders.
Yes billet and modular. I want to make it so you can change plenum sizes and entrance for tuning.
If your interested , I have worked up a full intake system from them but it's expensive and I need 4 committed guys for them to make a run of them.
As of right now I'm just buying 2 manifold runners and going to make the plenum myself.

Are you running some kind of a flex plate around your cylinders to keep them in place with 45 psi ? I have seen some guys mill the block down 5mm and make a plate to keep the cylinders from moving on motorcycles

 

Hi,

Yes, always interested. I'd probably want to see how we get on with our current one before doing anything just yet but as said always interested. PM me a price if we found two other willing buyers pls.

I have fitted a plate between the cylinder bores made by cncwerx called a cylindersupportsystem.

I also have uprated the standard heads bolts from 10mm bolts to 12mm ARP studs. The std ARP kit is 10mm but we wanted something with less chance of stretch. Took a bit of messing with the block but looks strong.

What sort of spec are you running at the moment and what sort of limitations do you see?

We believe the JCW turbo exhaust housing is too small for good BHP and for every psi extra inlet pressure we are seeing a large increase in exhaust manifold pressure, meaning the turbo is outside its efficiency range. We also have a full frontal intercooler. Its from a Ford Sierra RS500 cosworth.

Quite a bit other stuff going on but I have a small build thread on here, so can post up there.

Cheers

RW

 

Remember that extra spring pressure means more force on all of the moving bits of the valve train. Expect more wear and tear, and a (slight) loss of power to overcome that extra force.

In general, if you're not revving the motor any higher and your cam doesn't have a lot more lift or ramp rate, you don't need stiffer valve springs. However, 45 PSI is roughly a metric s**t-ton of boost (technical term! ) and might require just a little more spring rate. I wouldn't think it was a whole lot more required, if any, as in-cylinder pressures are several orders of magnitude higher than 45 PSI.

If you can get information on what the on-the-seat and over-the-nose pressures are supposed to be, check your springs. They probably haven't gotten soft like the old- old- old-school ones can, but it's worth knowing if you're spending big bucks on the motor. Even if you can't find the specs, it's worth comparing the springs to each other! Variants could mean springs that are starting to fail.

The "beehive" style springs were developed to avoid hitting any resonant frequencies, because the different coil sizes will resonate at different frequencies. Meaning that the whole thing doesn't vibrate at any particular RPM, meaning it won't break when seeing sustained RPMs near there.

I believe current metallurgy is noticeably better than when those were initially developed, so they may very well not be needed. Worth a check, though.

Very very much worth talking to your builder and/or machine shop to see what they have to layabout the springs!!

 

Sounds like your heading down the right road with your cylinder plate.

I'm going to try and do every thing possible to make the motor more efficient before I go the piston and rod direction. That means intake manifold and exhaust manifold. Then headwork , then the insides....

soon right now I'm stock motor, Owens turbo ( what a difference that made) huge exhaust.... 298hp/302Tq meth,manic Stage2+ .... Getting my stage3+ when I get back in town in a few weeks.

I'm going to have to go read your post

What is your desire for the car when your finish? street car? autocross? drag? bragging rights ? lol

 

Hi Steven, I like your explanation about dynos (post # 6) --- I always wondered how BHP was determined. Your process seems quite thorough and useful. I only mentioned the differences for comparison purposes --- those of us with bragging rights are quite sensitive --- lol, and there are people reading this who aren't aware of the differences.

My beehive RPM rating came from Beehive's literature. I don't expect to get anywhere near that RPM, but based on their reputation, they gotta be better than OEM springs. Also, I'm not building my '07 with "good engineering practices", just seat-of-the-pants, old-school experience. Been extremely lucky so far.

 

Ridindirty:

I only went down the piston n rod route as my standard piston skirt failed with a 1 inch by .5 inch part falling off. That happened with a held 1.2 bar of boost on our big big intercooler. UK fuel is up to 99ron which is something 93 in american terms. We can't get better than that at the pumps. IMO the high compression puts everyone at risk of this detonation without mega fuel if sustaining relatively high horspower (say 260 to 300 engine horsepower).

When we looked at it all, whilst the exhaust manifold is a bit crap, it is the size of the inlet to the exhaust turbine housing that just looks too small. For every psi extra you add to the inlet the back pressure in the exhaust manifold spirals up worse and worse. So we basically just decided that the turbo isn't up for producing much more safe bhp, so we will leave it producing 1bar and get more boost from a second much bigger turbo (that is the plan but of course we need to discover how well it will work). I'll be interested in anything you learn about the manifolds, so please share :-)

OBW: No worries about the rollers, it is something I have had the luck of exposure on through guys who build and programme their own rolling roads. They don't think much of a roller that cannot hold a car at a chosen rpm against WOT. SO I asked why and got a well detailed explanation (this was 20 years ago and we are still friends and he is my tuner now).

I ordered the supertech beehives and retainers. Without much more info to go on, i decided they would be "a good step forward" for now :-)

My Mahle bearings for rods and mains arrived today. Slowly getting there!

I'll close this topic and move back to my build. Maybe share some photos this weekend. Cheers
Steven RW