Cylinder head flow figures

[CastleMGBV8]

Just heard that the new TA Performance heads for the Rover have made it to their catalogue, still no prices as I think they are trying to decide what the market will stand, gossip suggests $2400-$2800 so not cheap at $1.6/£

Page 13 of the catalogue.

http://www.taperformance.com/PDF/TAPerf ... atalog.pdf

Kevin.

[Speed 8]

Just heard that the new TA Performance heads for the Rover have made it to their catalogue, still no prices as I think they are trying to decide what the market will stand, gossip suggests $2400-$2800 so not cheap at $1.6/£

Page 13 of the catalogue.

http://www.taperformance.com/PDF/TAPerf ... atalog.pdf

Kevin.

OMG have you seen the max. valves in those puppies?

...By doing this it puts
the valves on the center line of the bore which allows for the use of larger valves, up to
2.02” intake and 1.60” exhaust. ...

[kokkolanpoika]

I think TA-Performance heads valves are to big for rover 94mm bore. 96mm would work better.
I think those will make too mutch valve shrouding to cylinder wall?
Chevy 101,6mm would work lot of better?

[CastleMGBV8]

Tino,

The valves being on the centreline of the bore will help a lot but you would need a big capacity 5L + engine to do justice to those heads.

Kevin.

[spend]

I think you guys are splitting hairs. If they work well on the v6 cylinder geometry - and they've had plenty of development remember - why would you think there are problems?

This is one case where we should be thankful that the V6 was used in anger IMHO, and I'd be more inclined to take hints from that experience rather than question it IYSWIM.

[CastleMGBV8]

Dave,

Agreed, the V6 is 96.5mm and they have moved the valves on the V8 heads as mentioned so should work perfectly, be interesting to see how they work once they get onto the market and whether they are going to be effective for road or race only use.

Kevin.

[HairbearTE]

I think TA-Performance heads valves are to big for rover 94mm bore. 96mm would work better.
I think those will make too mutch valve shrouding to cylinder wall?
Chevy 101,6mm would work lot of better?

Shrouding is bad for sure but if they get those valve sizes into a head for the rover I imagine the trade off will be well worthwhile. That's a massive valve size for a rover engine.

[CastleMGBV8]

Bear in mind that TA are saying that the new heads will take up 2.02" inlets. the V6 heads have 1.94" inlets and 1.6" Exhaust vales which should be more than adequate for anything less than full race applications.

Kevin.

[POAH]

same thing with rolling roads I suppose people aways see numbers and take them as an absolute rather than looking at before and after to see the change from stock to modified.

Hi Dave

I have been pondering the criticism of my flow bench since you told me about it yesterday, always interesting when someone states 'categorically' that something is wrong and has a design flaw!ramble ramble

Peter

[burgesstuning]

Hi All

Been talking with my mucker Dave who does the reasearch and books with me, maybe we should all be quoting percentage change with flow benches rather than 'absolute' figures?

I agree with you about rolling roads Poah, I run an Old Clayton water brake. I get analogue readings and don't do print outs unless via spreadsheet. Upsets some customers till I point out they stay with us while we tune the car and get to see what happens warts-and-all. Most dynos seem to keep customers away so the only 'dyno experience' they take home is a bit of paper, we are more holistic and know how much people enjoy 'being there and part of it'. I will never be rich but enjoy what I do.

They seem to get wound up and niggly with things on that go fast news forum don't they!

Peter

[Darkspeed]

Here's a ramble...


Measuring the actual CFM increase has probably been encouraged from the old Superflow data and calculations which have a 0.43BHP increase for every increase in peak CFM. @ 10" WG

Fettle the head get a 10CFM increase multiply by 0.43 and then by the number of cylinders - taking the JE Merlin info as an example john heads initially flowed 110 CFM - = 378BHP with a fettle 120CFM = 413 BHP

Before everyone jumps in with ahh but this this and the other - we know this is just a quick and dirty wet finger in the air figure nothing more but like the stick with two marks its a gauge.


Another calculation from the old Superflow info is the VE figure for an engine which does allow a certain amount of Bullcrud detection.

Calculation goes VE = 5600 * (horsepower/(rpm*CID))*100 %

So for the Dyno graph on my 4.0

5600 * (232/5500*244)*100 = a VE of 97% which does not leave much room for improvement.

What it does allow for is an element of rearrangement of the formula to get an idea of what a particular combination could deliver

So BHP from av3.5/ 215? lets assume a very good combination giving 95% VE

Ok lets assume stock running gear and therefore a mild cam giving max power at 5700 RPM

Power = (95/560000)*(5700*215) = 208BHP

A 3.9/241

Power = 233BHP

That have a look at that 4.6 with a similar cam

95/560000*5700*278 = 279BHP

A 5.0L

95/560000*5700*305 = BHP

rearranging again for what RPM would be needed for our required horsepower at our 95% VE

I want 270BHP from my 244CID and its unlikely I will get a better VE than 97% from it

RPM = 1/ ((VE/560000)*(244/270))

=6522 RPM Hmmm not sure that getting that figure for continuous RPM will be cheap

From an old rally report I have the TR7 figures of 290bhp at 7500rpm and after some serious mods 320 at 7500.

Running the VE figures

We have figures of 100% and 111% respectively.

From some of the dyno graphs

Cobra Tone

302BHP @6010 on a 4.8L = 97%VE looks like a familiar number for a well put together Rover


dnb Griff 500

319 @5700 0n a 5.0L = 103% VE looks like a lot of effort has gone into that one

Have a play with the formula and put in your own figures

That much quoted 250BHP from a 215 or a 241

With a VE of 100% they are spinning at 6500 and 5800 respectively

I need to get out more.......

Andrew

[burgesstuning]

We have played with the flatplane crank 3.5 TR7 motors, they are totally different from 'normal' engines, extremely fast revving and full race so maybe not in the same league for the maths, sad thing is the blocks split after a while! The SD1 Vitesse race engines were physically bigger (around 1.4" thicker) this prevented the horrible tendency for SD1 type V8s to flex and nip the pistons a little and drag the bhp down. Figures are fun to play with but don't always tally. The other problem with the Vitesse race cars were they were physically smaller than the Vitesses you or I could buy...they were homologated and built to the minus tolerances!

We are in the process of buying a modern eddy brake rolling road, we feel we have to move into the 21st century We will store and publish all the graphs we end up with...especially any V8 stuff for you allto mull over. It will be a sad day to sell my old Clayton Rolling Road, I have used it for 24 years!

Peter

[ChrisJC]

Is the old rolling road going on eBay?

Chris.

[burgesstuning]

Hi Chris

We will sell it direct from here, not bothered with ebay, we are wanting £2500 plus the dreaded for the rollers or some sort of deal can be arranged. We would like to spend time on the rollers with whoever buys it so we can pass on a little help and make sure they are comfortable with it.

Just had my old V8 MGB on the rollers
http://www.youtube.com/watch?v=XveBgkUEd4A

Peter

[HairbearTE]

Just of interest, does anyone know the VE for one of todays F1 engines? bet it's pretty astonishing. I know some pro stock drag engines are shooting for 120+..