MK3 16v ABF - Dyno Results before and after 261 deg Catcams

Pre-cam change dyno results from a Mustang chassis dyno which "uses an Inertia load as well as an eddy* current brake load to simulate the "actual load (combined aerodynam*ic plus rolling frictional load) that the vehicle would experience when in motion"...

Its a single roller dyno so there is less frictional losses from tyre pinch associated with twin roller dynos



All three power runs together with AFR on the right and combined wheel BHP and torque (ft lbs) on the left



Third power run

Mods are;

Opened/drilled airbox with pipercross filter
Bored/polished TB
Custom Code chip
Supersprint magnum VR6 exhaust
QEP L+B flywheel

intake air temps were high @ 25 degrees

fairly pleased with the results.

However the AFR is a bit concerning. Seems like the chip dumps a load of fuel in @ 4000 rpm and the ignition timing isn't advanced enough. Would like to see it higher at 0.88. Goes normal again at 6500 rpm. Seems like the generic map has only been alterered between these points.

Torque curve is rather flat too... which is what i'm hoping to solve with these high lift/ short duration catcams.. want to pull it up.

it also dips between 4800 and 5300 which is strange.

If anyone cares about flywheel then the guy reckons between 8-12% for this car on this dyno so between 168-175 bhp

Thoughts?

 

Right.... cams have arrived. Got a 30% discount on them for doing these power runs which was nice.

Lightweight lifters should arrive tommorrow.

Anyone got any helpful advice before i start.. Sort of know what i'm doing but never really don't this before.

The only thing im not really sure about is removing the timing chain wheels from the cams...Any tips for doing this easily? Does heating them make them any easier to fit to the new cams?

cheers

 

I've not seen Mustang graphs before...
Which is measured power ATW?

The Engine Power (HP) Max is the calculated power at the crank 9measured plus losses) is it?
From the figures, it seems to be.

Torque seems about right too.

Looks like no coastdown losses are shown...so if the peak (HP) readings are at the wheels, then you are already making more than mine does!
Mine makes 151-153ATW with all the mods so far.

 

Its on the same axis as wheel torque on the top graph... 155, 155 and 156 on the third run.

Its a retarder dyno, which uses a non contact eddy current brake to retard a light roller with little inertia. It allows the rollers to accelerate at a fixed rate when the power of the car is applied to them, so with a 100bhp car, or a 1000bhp car, the acceleration rate is constant.... so as it measures power directly at the wheel there is no need to calculate flywheel figures. It cost 125,000 so hopefully its reasonably accurate.

Inertia dynos are a simple force = mass x acceleration, and transmission losses are estimated through the coast down method. they are very dependant upon gear ratio as you need to run the car as close to 1:1 a possible. If you dont and say you run the car with a mechanical gearing advantage the car will accelerate very fast, as will the rollers.

The coastdown method can be misleading as any slight increase in friction, such as tyre pinch, can slow down the rollers quicker and thus give huge transmission losses and a high flywheel figure/ low wheel figure.

its okay. It dips a bit which i think is related to the chip... More fuel is put in but the AFR (lambda reading) gets richer as maybe there isn't enough air?

I doubt im making more at the wheels than you. Think yours is probably making over 160 at the wheels. You have huge transmission losses. I think 20-25 standard is fine... okay you have a LSD and lots of camber so maybe 25-30. you probably have 190 flywheel and 160-165 ATW. I know i would prefer to have 160 at the wheels than a theoretical 195 at the fly.

Using that formula from the puma racing fella and carfolio stats you can get a rough idea of standard transmission losses....

Rolling resistance power is 0.013 x car weight x top speed / 375

= 0.013 x 2600 x 134 /375 = 12.08 bhp

Air resistance power = Frontal area x drag coefficient x 0.00256 x top speed cubed / 375

= 20.56 x 0.34 x 0.00256 x 2406104 / 375 = 114.82

114.82 + 12.08 = 126.9 bhp

148 - 126.8 = 21.2 bhp losses

Either way, yours was useful to you as a modification tool, in the same way that mine will be useful to me to see the effect of these cams, regardless of which one is right

 

Could be...dyno lottery again.
I know mine made 118BHP ATW standard on a MAHA. (151 ATF calculated)
Same dyno it now makes 151-153 ATW and around 190-195 ATF calculated...so a gain of 40-45 BHP which ever way you dress it up.

Thing is, mine makes the same ATW power on the 2 Dyno Dynamics dynos I use as well (151-153)...so I'm not sure mine is actually making any more than that.

Regardless of losses...lots of camber, lots of toe out, big brakes dragging slightly (?) and a diff may well rob a few BHP...but I'll happily trade a handful of BHP for the better cornering.

It doesn't really matter what the figures are...so long as from start to finish to get a good gain. I'll look forward to seeing the end result.


Did you go for the SEAT lightweight lifters?
The lighter INA versions?

Titanium retainers too?

Can I be nosey and ask which cams you are planning to run?

 

I went for the lightweight lifters from USRT which you recommended. As the dollar is so low against the pound it made good sense as they cost 127 including fedex priority shipping.

Didn't go for ti retainers...

i just didn't want to put new cams in with 123k followers.

The cams i have gone for are catcams 7661207

Spec as follows;

7661207 ►


INTAKE / EXHAUST

clearance [cl] = 0.00mm

duration [0.1mm+cl] = 261/261

duration [1.0mm+cl] = 221/221

valve lift [cl=0] = 11.20mm / 11.20mm

peak angle = 110/110

timing = [1.0mm+cl] = 0/41 / 40/ 1

lift at TDC = 1.05mm / 1.05mm

I chose them due to;

> small lift at TDC (<1.1 mm) so good idle and less chance for ECU/lamda to have a wobbly with unburnt fuel / pulsing

> Timing similar to standard ( 1/38 / 1/39) with one less in overlap, so less time for A/F mixture to move straight in and then out of the cylinders

>Higher lift/ fairly short duration with peak lift achieved quicker, opening the valves faster to where the 16v head flows well, resulting in an improved torque curve, hopefully a wider power band and slightly increased top end with the added duration. - Lightweight lifters should hopefully reduce the strain on the valve train with faster valve opening.

> They have been designed to optimise standard flow rates.

> They were cheap! matt from QEP (UK distributer) sorted me out with a great deal for doing these power runs so he can use them on his website (www.catcams.co.uk)


Time will tell if they are any good. Matt seems very confident in them. I will be really happy with 5-7 bhp ATW, but its mainly the torque delivery i want to improve

 

how much were teh cams?

 

300 including VAT

 

Good price...

I'm keen to see how the graph compares between a pair of those and my set-up...and eventually against a paid of Schrick 268s.

The Schricks have more lift, but more duration to hurt the ABF ECU.
I hope it works out...I got about 10 BHP from my inlet, after mapping...so you should see the gains you are looking for.

Looks like a good option for the ABF. As you say...time will tell.
When are they going in?

Are you keeping the standard valve springs?
They should be fine...just maybe a bit weak after 123k miles?

 

There is a good thread somewhere all about changing cams on a 16v. By GKV I think...it was use for me, that's for sure.

Just make sure you spin the engine with the plugs out by turning the crank, to double check it spins before starting it!
You'll be fine...

Also, use the sealant stuff (VWs is Kermit green) in the corners of the rocker cover gasket where it goes over the cam caps...it'll save you some leaks!

I can't help you there. My Schricks came with chain wheels on.

 

This thread HOW TO REMOVE / REFIT Cams will tell you most of what you need to know

Although I`ve never swapped the cam chain wheels, so I can`t help you there, sorry.

 

Cheers

Your guide will be most helpful

will have to play the chain wheel dilema by ear.. just got to be careful that i dont crack anything.

 

Okay... cams are in.

Slight problem with the cam-cam timing though.

When I pulled the cam gear sprocket off the ABF inlet cam there was no keyway machined into it.... so although there is a woodruff key in the catcam there is no way to align the chain wheel to the standard timing marks!

There is also no lock plate mark machined into the end of the abf or catcam inlet to align it to the cylinder head... so i was left with no way to put the chain wheel back on either cam to the correct timing!

phoned matt at qep and he was bewildered as well. He gave me an internal vernier he had lying around so i used a dial gauge to set the inlet valve lift at TDC to 1.05 mm (as specified). I know it would have been better to set it at peak lift but i didn't have a crankshaft timing wheel thingy.

put it back together... started first time... and ran the tappets and cams in for 25 mins

Problem is... the idle is awful, and i am not sure whether its the ecu having a wobbly because of the lift on overlap and the MAP pulsing (AKA essthree's experiences) because i have got the cam-cam timing wrong or because the cams are too fruity.

I took it for a drive and it is good.... much more urgent around 3500-4500. Idles like a pig though.

As i have an internal vernier, would it be worth retarding the inlet cam slightly, maybe to <1 mm at TDC

timing figures for the catcam inlet @ 1mm valve lift is 0 degrees anyway...

any cam gurus advice would be much appreciated

 

can I ask what size exhaust piping are you guys using for your exhaust systems?

2.25" or 2.5"?

 

IMO, you need to set them up at max valve lift - get a crank degree plate for about 10 and then readjust (Burtons have them as do other tuning shops)

lift at overlap does screw the standard ecu map sensor but 1.05mm doesn't sound like too much to me - I think they are slightly out on the adjustment and possibly too advanced presently

 

cheers

thought it was better to set timing at peak lift but didn't have the car to go and get a crank degree plate.

Will get one tomorrow and check the timing thoroughly, and then maybe retard it 1 degree further so there is no overlap if its still playing up.

took it for a long drive.... pleased with the midrange increase.... much more responsive from 3500 rpm.

Hopefully can get this idle issue sorted

 

thing is, retarding the timing will take the edge of the cam, it might make it idle better but then you will loose some of the advantage of the hot cam

 

How goes the cam timing?

 

Both our trolley jacks are being used to take the gearbox out of the JCB loader while the clutch packs are being replaced [:^(]

Got myself a timing disc though, so will try and get it done ASAP

Rob.. retarding the cam would be a last resort... that or going back to standard exhaust cam. Hopefully doing a proper job on the timing should do the trick

 

Checked the timing today and it appears the inlet is slightly advanced, probably about 2 degrees.. got a more accurate TDC reading with the dial gauge as the mark I used originally on the crank pulley was out...its a shame i have no mark on my flywheel.

Was about to adjust the vernier but the rain has set in and i'm doing it outside.

Hopefully thats causing the idle issues. The ECU has learnt how to idle better though as its not as bad as at first. At 3-4000 rpm my mpg shoots upto 30+... keep it below 2000 rpm and it plummets.

Is it worth checking the exhaust cam? The cam pulley mark lines up to the cyclinder head and the mark on the rocker cover. I might check it to reasure myself, but Its a right pain in the backside setting up the dial gauge each time.

I have left the ISV in some petrol as well, as the idle has been slightly rough for a few months.