Braineack

iTrader: (62)

i want to see this impressive torque curve!

miatauser123

iTrader: (7)

I'll get you guys a picture of the plot if they still have it saved on the machine. I was thoroughly impressed though.


Moved from previous page:

Started my day out with a nice coffee... Laptop was charged.. delicious steering wheel was awaiting the ride to the dyno..



I had my map setup as a hybrid boost comp table and things were going great - I unplugged the waste gate line and basically tuned it perfectly at 14 psi across the board. Then basically copied the cells all the way up and let boost comp take care of the rest. As I started to ramp up in boost things were going beautifully. Boost comp was doing it's thing and making my job easy.



As I got close to 20 psi the car started to make some really impressive numbers. 380 something at 20 psi. My torque curve was seriously impressive. Not a single bottle neck in the system holding me back. The BEGi manifold 100% solved my torque curve issues. It was basically making more power with RPM and didn't show signs of choking out at all.

Now getting near the 24 psi mark I started to notice a misfire at around 6500 so I checked my timing and added a little fuel. Ran it up a couple more times with the same problem.. The timing was looking pretty retarded for E85 so I gave it a degree or two more and it went away. Then I moved it up a notch and got one pull out of her before the failure in cyl 4. The pull itself was actually not awful, but just at redline I let off and you can hear a ticking noise all the way back down. The car shut down pretty quickly and would not fire back up.

Pushed the bitch off the dyno and headed to the bar.

Now I'm debating building a nice VVT head or going with a cammed out non-VVT built head...

MicaCeli

iTrader: (1)

Oh no :( Nice numbers though.

sixshooter

iTrader: (12)

Just curious what makes you sure it is a valve? You said the spark plug wouldn't back out. Do you think you melted the electrode off, by chance? I've seen it done on a high boost car that also melted the pistons.

miatauser123

iTrader: (7)

Well my EGTs weren't crazy. The noise and the fact that the other plugs looked great.

Leafy

iTrader: (1)

Its really easy to tell if you just pull off the valve cover.

Braineack

iTrader: (62)

i want to see this impressive torque curve

18psi

iTrader: (76)

Do this.

It takes all of 5 minutes.

And yes please post that lat plot asap. I'm all antsy in my pantsy.


As for the 6d vs 4w heads:
Are you willing to give up a good 1000rpm worth of that delicious torque curve down low for topend glory? Its not too bad of an idea if this is RACE CAR and you wanna hit serious numbers.

ORR,
with all your connections I'm sure you can probably get someone to grind you some nice vvt cams.

I know sav was working on some, and there are like 1 or 2 mild ones available from others now, but seems like that's still a very limited area for upgradeability on our cars.

Leafy

iTrader: (1)

Webcams will grand you anything you want. But I've seen someone trying to run MAN cams on a VVT head and needed to do some die grinder work on the head to clear the lobes.

18psi

iTrader: (76)

He'll probably have a ton of die grinder work done to the head anyway to improve flow, so who cares. If its done right and doesn't compromise anything structual (which I heard was the problem with getting big vvt cams into our heads) or other components

aaronc7

iTrader: (8)

I'm having to step up to a 33mm bucket (from 31mm) in order to run my cams from Web. Turning out to be a pain in the *** to get the head machined appropriately, but it can be done. I don't know what the limit is, but to get much more than stock lift on a cam, you're probably going to need to do some machine work on the head. I think mine are spec'd to get around .420 lift, to give you some reference. With 'big cams' you're surely gonna lose some bottom end, but hopefully be able to make power up to and past 7500rpm (at least that's my plan)...just moving the powerband up more.

miatauser123

iTrader: (7)

I'm not going with a big cam. No flucks given about making more power. This is a retarded amount of power and my torque curve leaves little room for improvement.

I will go with a bigger valves but otherwise I'm not interetsed messing with the head. Totally happy with how the tune was going before this point.

18psi

iTrader: (76)

Well then you're set. Head refresh + 1mm over valves + some stiffer springs = glory

I'd at least have em clean/deshroud things while they're in there. Maybe some mild pnp?

2manyhobyz

iTrader: (4)

This is a VVT head if I remember right(?) Is there much valve overlap on this head design? Or you controlling it somehow?

miatauser123

iTrader: (7)

One of my buddies who was there snapped this at some point. Not the best run we got out of her but you can see the tq is quite different than my last dyno visit.

This is at a lower boost pressure with no further ignition timing. I was happy with the way things were headed.

18psi

iTrader: (76)

You revved it to 7500? Maybe that's why the valve decided to call it quits?

The torque curve is nice. At least when considering this is a regular 'ol 3076 and not one of the fancy billet wheeled gtx or efr snails.
And since that's a low reading mustang I can't even imagine how stupid quick it probably was even at 360

miata2fast

iTrader: (2)

You may want to look at the thread that BogusSVO has on valve springs. He sheds light on the fact that high boost motors need more valvespring.

I regularly took my old stock 95 head close to 8000. The big difference is I am naturally aspirated, and you are running 20lbs of boost. That is a lot of force trying to hold the valves open.

Braineack

iTrader: (62)

What IM manifold are you running? I'd just love it if the spool was a little bit more linear as opposed to slowly working to expontential.

miata2fast

iTrader: (2)

Could someone please explain the odd looking graph to me. Did they all look like that on the same day, and is this one of the later pulls?

When I first saw it, I assumed the dip is where the failure occurred. Am I right?

miatauser123

iTrader: (7)

I'm running the BEGi intake manifold. All of the pulls did not have the same result - This was actually after switching to a Manual boost controller. The MAC valve actually did a better job of spooling, but it had caused a strange dip at 7k in boost for some reason.

Also - This could be without VVT activated.

What odd dip? You must keep in mind any dip in that curve is probably a matter of 5-10 HP or TQ. This is a really flat curve.