Well that last part really has me scratching my head. Hitting a wall ~54-5500? Is the engine breaking up above these revs or is power loss in steady decline? Would really like to see the dyno graphs with a/f.

For anyone who doesn't know, I'm running an AS&M monoblade. They supposedly flow ~1300 cfm but I haven't really done the math on it yet. If you're calculating air demand without taking into account some losses, then you'll likely come up a bit shy. Lots of variables for sure but you could start with a pressure check before the throttle body to see how well things are upstream, then look at the map readings or ported source vacuum at the plenum.

I still keep thinking that something else is wrong here though because of the peak (54-5500 rpm).

Want to think a little more on this one..... been a long day.

-Mindgame

 

With the wall being at that low an RPM, I would take a look at the valvetrain. Maybe losing control of it beyond this point? Is this a solid roller?

Hrmmmm....

Dave C.

 

Hyd Roller with Duals @ 155 seated and 441 rate.... shouldn't stop that early even with a aggressive lobe.... never know. I don't know the cam lobes though so i can't tell ya there.

Bret

 

I'd be tempted to pull a couple and throw 'em on a tester just to make sure he didn't get a crappy batch or something weird before I started killing myself to find the problem. Can't hurt, and should only take a half hour or so.. Just a suggestion. I like to eliminate problems from the top down.

Dave C.

 

Just to prove I don't have any secrets..... Grind # 3120/3370 HR112. Not sure what Comp did, but they added some lift to the lobes.

According to Comp, the AFR Hydra Rev kit does not fit Trick Flow heads so we didn't add it back but just looking at it, I'm not sure why they don't recommend using it.

It did seem to pick up some yesterday for no reason at all except about 25 more miles on it. We put it on the dyno with about only 20 miles on the motor so there may still be more ring seating to be done. Instead of hitting the wall @ 5400-5500 rpm it did it a little higher @ 5600-5700 rpm and made a little more power.

Basically I've ordered out 36 lb injectors and am going to just drive the car for a while to see if the rings might want little more break-in time. Like Mind Game, sometimes the best thing to do is sleep on it a little just to let the meal settle some.

As usual, I appreciate everyones input and help.

 

Those lobes are tame enough man... should be ok in terms of valve control.

You put the bottom end together Denny?

If so what rings did you use?

Bret

 

Scott from A&S did the final assembly and a combination of Watts Racing Engines/Wayne Calvert on the machine work.

Lunati custom thermo/friction coated pistons with J&E rings and Howards rods. I bought the rings for my other J&E pistons and decided to bump up the ci to 398 instead of 385.

 

Tell him to Try Total Seal quick seat.... I've found on NA motors that stuff is great for getting the rings to seat faster. Blower motors I stay away since they aren't going to load the rings to 100% till the motor is really dialled in so you want them to take longer to seat in.

Bret

 

Thanks!

 

Yeah, come back to it after you've gotten a good seal. Take it to the track and make some runs, either that or find some long (deserted) on-ramps and let her rip.

Then update us on where you're at. I can tell you this... if this thing can turn 6500-7000 rpm, you'd better start looking at the monoblade.

Good luck.

-Mindgame

 

What was your duty cycle w/ those 30lb injectors? I'd think that you would have those maxed out. FYI - I'm running 42lb injectors and a monoblade in my max effort head/cam package.

Also, what air induction kit are you using? I know they pretty much all suck for the C4s. I think Vararam is still working on one for us.

 

Didn't even bother checking duty cycle as we were using a wide band 02 on the dyno and saw an upward curve starting @ 6500 no matter how much we added to the fuel on top.

Scott has the latest update on his dyno software and I'm not sure if his compensates, but on most you need to subtract about 400 rpm to get the true Fuel/Air reading at the rpm you’re looking at. Regardless, @ 36-38% added fuel it didn't change any so instead of scanning, we just called Summit.

Got one of those Breathless Industries intake systems and quality wise it’s a real piece of crap. I've picked up one of the A/O engineering Ram Air outside intakes that go into the front bumper. Got it in the bumper but haven't done the ductwork into the air box yet. Still haven’t made a 100% decision on whether we are going to build a separate air box or run it into the Breathless Box.

I know there has been some debate as to whether or not a Ram Air adds power, but we did a little experiment that has me sold. We added plumbing running it to the TB and stuck a good sized fan on the other end. We picked up 13 hp. Think there is a reason the NHRA made the Ram Air guys run one class higher.

Mind Game….

It’ll rev as long as the computer wants to let it rev (I think). We usually take it to 7000 rpm every time on the dyno and either run into valve float or computer issues (Whatever?) in the 72-7300 range. One of the two, but with 222 cc intakes and real light rotating stuff, it like to rev.

According to Performance Trends software it only needs a little over 920 cfm of air @ 7000 rpm. I’m up for anything but the dual 58mm TB is suppose to flow over 1050. But then again, something is causing a vacuum on top.

Know something I don’t? I’m all teeth n ears.

 

Jodon did testing back when he had that "big" motor and he ALWAYS picked up power going to a bigger TB. maybe he will check back in and give us some of his old results

 

He's still in bed.

 

You might be onto it there LT4POWR. I'm even running bigger injectors on my 383 and I have a little less cam and a lot less air though the heads than this bigger cube motor. Mine wasn't happy with 30 lb'ers (running around 90+% DC)so I went up to 36's. Basically he can add fuel all day long if the injectors are maxed and it wont make a hill of beans different. Wide open is wide open!

Dave C.