The V8 Owners Forum -

Same as rover stage4 "race" heads..

John Eales say 184cfm@28"

Same as what we found and posted on flows back in January

Andrew

Wild cats still flow over 233cfm @28"?

Spoke to V8 developments, Shaun says that also wild cat heads need lot of work to give good compo.. He also recon stage 4 race heads to get better low/mid range performance..
I did not get an answer why? John Eales and V8 Developments dosen´t like wild cats..

Conclusion nothing really new compared to full reworked Buick heads.

" John Eales and V8 Developments dosen´t like wild cats.. "
he doesn't like merlin heeads, doesn't like wildcats, sells "stage 4" heads and says they are "better", is it just me?
Mike

Same point as always, out of the box the Merlins match stage 4's, I would love to see what Peter Burgess could get from these castings.

Alan

I tend to think the same, wait until there has been some development..

..but then again the TA heads just might be better developed straight out of the box after their V6 experience?

Anyone wanting to develope a pair of ali buick 300 heads can find mine on ebay right now, complete with set of Titanium big valves.... pm me forum members if you want to finish auction early

I thought that JE had done some work on the Merlins (I will have a chat with Roy Burrell ) and the outcome was that even with further work they only flowed as well as the UBV heads already available - the isssue then is do you buy Merlins and pay £600-700 to get them modified only to find the same flow capacity.

Looking at the heads they are ham strung by the push rod pinch point and a design to use stock manifolds bigger numbers would need a taller inlet port and the associated re design of all the perifferal components - which would have really stalled sales.

The Merlin heads are a compromise for reason of economics - they are good for what they provide but as far as ultimate performance for RV8's they offer no significant improvement on whats already available and nor will they in the future.

Andrew

spend wrote:I tend to think the same, wait until there has been some development...

The trouble here seems to be there are still no proper back to back flow figures for merlin heads and other "ported" RV8 heads, done on the same flow bench under consistant conditions. It is pretty obvious that the various bits cast into the heads are intended to optimise flow on pretty standard mmanifold (I suspect EFI, but again little information to confirm this) so for a result that means somthing it would seem to me a good idea to flow test these heads with a manifold bolted on, just a narrow radius on the gasket face of the port will be meaningless. Secondly these heads seem to be optomised for low lift flow, so lets see some figures for low lift flow to compare. finally some results were obtained with the valves removed all together, these are totally meaningless as the valve in any head iis key to getting the flow over the seat, pulling the valve out can result in a reduction of flow in the order of 35%.
The couple of guys who have built engines using these heads don't report results "similar to stage 4 heads" they report results a very large amount better, MGbloke reports 320bhp out of his engine, looking at the rest of the spec of his engine, especially the cam figures suggest that under certain circumstances these heads produce quite remarcable results. It is very interesting that another tuner using a cam he believes to be better that has about another 15 thou lift cannot get these heads to work, that would suggest to me that moving the valve too far from the seat on these heads causes the flow to become turbulent over the seat and flow suddenly drops away and these heads are designed to work with a specific aproach to tuning.
As I say results from engines built by people who I have alot of respect for (members of this forum) definatly suggests that these heads are good when used inteligently in a well ballanced package not too far from standard rover and that there is more to the story than peak flow figures.
Sorry rant over
Mike
edited to replace MGBV8 with MG Bloke

The meaningless test showed that no valve reduced flow by 35%!!

Thank goodness for people prepared to do meaningless testing....

kiwicar wrote:
.... finally some results were obtained with the valves removed all together, these are totally meaningless as the valve in any head iis key to getting the flow over the seat, pulling the valve out can result in a reduction of flow in the order of 35%....

and what was on the upstream end of the port? an inlet manifold or just a radius?
I think you will find the word can in there. A simplistic aproach to this testing and looking at bits of the data and inlet tract in isolation is exactly why results from engine builds do not reflect raw flow figures of the heads.
Taking part of a sentance of mine out of context like this is a reflection of what I am trying to explain in the post and why I have tended to keep out of this subject to a greater extent than most subjects on here. This is a complicated subject that does not lend itself to reductionist thinking.
Best regards
Mike

It was mentioned in a local race car magazine here that did a feature on Ian Wilson's racing TVR Tuscan that TRS (Ian's company) were working with TA in the States on developing and trialing their new hads.

Ian is currently running the 5.0 Rover engine with Wildcat heads out of his ex TR8 in the lighter Tuscan racer. It is putting out over 500 bhp and weighs 870kg - Ian says it's the fastest accelerating car he's ever driven.

However to trounce the Porsches and Vipers in this class of racing he went to the States to work with Mike at TA on these new heads. Apparently, according to the mag article, they flow 297cfm, come with 1.94 inlets, although 2.02 can be fitted. It took a lot of time to get the rocker gear right, and the valves are slightly inclined (13 degrees I think) much the same as a Chevy.

Ian expects well over 600 hp from them. 100 sets have been ordered in the first batch and I understand a pair are already being trialled in an MGB racing here. Second batch is reported to be 300 sets and I guess TRS will have distribution rights as it seems they have sunk a lot of money into all this.

I had a Merlin head compared to my homeported big valve 4,6 head on same flow bench. The merlins flowed up to 20 % more than the modified 4,6 head up to 0,4" lift where the Merlin flow just leveled. They still flowed more than the Rover head. I need to find the chart for exact numbers. I also took the car to RR session with both heads and Merlins were better at low revs, mid range was about the same and again Merlins were better at higher revs. With Performer manifold and 500 cfm carb the power increase was 12 hp. Swap to Wilpower manifold gained another 20 hp. In retrospect I hoped more but there are still details that need attention so hopefully there is some room for improvement. Single plane manifold did ruin the low rpm response compared to performer manifold which was to be expected. I am thinking about fitting EFi so that may changes things considerably. Real steel dyno chart in their catalogue is with single plane manifold and carb, not efi.