Jason Moyle Racing

And just to prove we're not totally 8v biased!....
 
Mark Liney came to me via various recommendations. He had been struggling to get results from his circuit race MK2 with ABF power. Mark had spent his hard earned on some DTH Jenvey bodies and Omex management and only gained 4hp over the std plenum. So after one too many Clio 172's had passed him on track Mark came looking for a solution.
 
His original request was for a ported head and some decent cams to enable him to reach the 175hp at the hub's his power to weight target permitted, and as he was only 15hp shy it wasn't going to be too difficult.
 
My original plan was to have some custom cams ground to suit and see how close we could get to the target as a std ABF head flows enough for 200hp, and combined with the ITB's I wanted to see how little port work was needed to top up the rest based on the powerband I wanted to achieve...as the class is power to weight restricted I wanted to keep the torque up as much as possible, so keeping the port sizes down would help...only making them as big as they really needed to be.
 
However, during a chat with Mark when he dropped the car off he said some tame road cams had been fitted in an attempt to help the power which they did as he certainly noticed the difference...the car was noticeably slower!
 
So the o'l grey matter kicked in again and I figured a look in a different direction was now worth a try. After quizzing Mark he told me the cams had been fitted by a VW specialist so he assumed the timing was right but they just didn't suit his set up, but being tame 260 hydraulic profiles I was confident in what I was going to find if he "just let me check the cam timing to be sure"...
 
Upon removing the bonnet there was also something else obvious...how was the engine getting a decent supply of cool air with the radiator filling the front panel...with the grey matter now smoking away I had another idea. While I was having a poke around I popped off the air filter to measure up the trumpet lengths and found a throttle linkage hanging loose but working...hmm.
 
I wanted to run the car in an "as delivered/last raced" condition so it was off to the rollers a couple of days later, which highlighted the reason Mark had been struggling on track when 139hp at the wheels popped up on the dyno screen. Standard ABF's on the AP Motorsport rollers show low 130's normally so with Mark only seeing 4hp from the ITB's the puzzle pieces where falling into place.  Alvin at AP thought I was packing up early when I dropped the bonnet back into place...oh no..."run it again"!....132 at the wheels!....a 7hp loss because the engine now had no source of cool air due to the rad location.
 
Not wanting to drive the car back with the loose linkage I re secured it but it was evident we weren't getting full throttle either...so with that fixed we did another power run...it's surprising how easy it is to find another 7hp at peak power, plus a decent amount right through, just from opening the throttles all the way!
 
Back over at the JMR workshop I stripped the slam panel off for a better look and figure out how we were going to drop the rad down...easy enough...remove the crossmember it sat on and lower it into the bumper area where there was plenty of cold air feed available, with the grill area taking care of the rest and a decent size gap now available to feed the new inlet set up I had planned.
 
A check of the cam timing while at the workshop revealed what I suspected...badly set cam timing...actually very badly!....with 1 thou lift at TDC on the inlet and 34 thou on the exhaust the timing was retarded and badly phased...so armed with my trusty TDC finder and a dial gauge it was back to the rollers.
 
A quick run to check the power again on the day and give me a starting datum point gave a direct comparison for the next run a while later with the revised cam timing...I gave the exhaust a touch more to bring it up to 43 thou and the inlet a lot more to make 65 thou, so we now had much better phasing and advanced timing.

 

With Alvin turning the rollers once more we had a 1hp loss at 2000...shock horror!...but I was confident that would probably be the last we would see. From 2,500 up the cam timing re set gave an extra 3hp minimum, through to between 11 & 8hp from 4,500 to 6k, and back to 3hp extra at peak...but now with a leaner mixture as the engine was pulling in more air. Some extra fuel added another couple of hp to peak, as did more ignition timing, where we ended with 155 at the wheels...so far so good, but the inlet length was still too short so back to the workshop for the next phase.
 
The extra length I wanted to run meant "bending" the trumpets forward...not literally obviously, but with some curved extensions that I had a very clever fabricator make up for me. These both tipped the trumpets forward and would add an extra 35mm to the final length I wanted to run along with the 120mm trumpets...so back to the rollers one last time.
 
With the original 90mm trumpets fitted to the curved extensions we had some small but positive gains at the low end and some worthwhile (6-7hp) gains at both the mid range and nearer to peak, plus a couple more hp at the top. Last but not least the 120mm trumpets were fitted. Another couple of hp was gained at the low end but with a couple lost in the mid. Alvin was game to swap them back but I wanted to keep going...good job too...there was another 9hp to come at 5500rpm, +7 @ 6k and an extra 5hp at 6500, plus a couple more again at the very top of the power band. We swapped between the 90 & 120mm trumpets to see if there was any fluke readings going on, and the shorter trumpets did indeed give a better result at a couple of mid range points but I elected to run with the longer ones as there were more gains than losses, and the engine had a much more noticeable "bark" on the 120mm trumpets, so its certainly drawing harder.
 
All in all we ended with a peak of 162 at the wheels from our 139 starting point (though I believe Mark was racing with less than that due to under bonnet temps) and holding 161 @ 7k.
 
The right induction length can clearly pay dividends, but so can details like temp and really simple things obviously like throttle operation. And as for cam timing...I'll reserve judgement in print of the specialist Mark had fit and "time" them. So if you have performance cams fitted and the results are less than pleasing you now know one of the reasons why.
 
As for this project, there are plans for a much better exhaust manifold as I suspect the current ebay "shiny special" with it's short primaries being a part of the mid range drop, plus it wont work at all with the new cam specs....watch this space!
 
Oh almost forgot....Mark ran the car back on the designated hub dyno 2 days later where they agreed with the sub 34ibft mid range increase but said there was only a 4hp peak gain rather than the 20+ I'd seen...go figure on that one! Mark said the most important thing is what the lap times tell him, I guess 12 seconds a lap faster (in traffic!) at Snetterton says it has more than 4hp to me.
 
The Clio's were still a problem, blocking Mark's vision in his rear view mirror ( as he cut through the traffic from a slippery qualifying position at the back of the grid to end up involved in a minor shunt...Mark claiming he now needs much better brakes with the extra power to slow down!















And finally....the real net gain from the above....