hello allmotor gurus, my setup is a b20 vtec, ycp type r pistons, stock rods w/arp, gsr head, tri-y header, performer x im and toda c cams. my shelf is a black dc2 daily driven.


i went to dyno and saw that the power band is falling too quick, any idea what can be happening?????? thanks in advance


without cat

sube

with compleat exhaust

imagen jpg

 

You could use some more duration. P72 head + PX IM is going to have high velocity/charge momentum, and be matched later intake valve closing events.

I like the combo you have. Keep at it.

 

OK, BUT WHY YOU THINK IS THAT HAPPENING, CAM TIMING??

 

lol whoa. all caps haha. it can be a number of things. my opinion:

- is your head stock? probably doesn't flow enough
- Toda C's doesn't have a lot of duration. maybe a bigger cam?
- the characteristics of a PX with its long runners usually peak at around 8-8.5k.
- insufficient header - or exhaust flow. what kind of Tri-y u using?

like Rocket says.. seems like a good start for a simple setup.

 

I'd be happy with it? I would get a better header and 3" exhaust....but **** - use this with a 4.7 FD and that is an awesome daily

Why the fascination with rpms? You're holding torque to 7,500....don't worry about it

 

i want power until 8500,
i will try better header
i have a set of buddyclub iv cams thAT can test
also have a victox x to test
maybe i can reach 220 whp

 

As good as the PerfomerX is the runners are the wrong shape and length for a 2lt engine with a cam that has good duration and if the header/exhaust setup is not at its best it hurts high RPM torque even more.

 

performerX is not a good choice for a 2.x+ motor. Like Dave said, too long of runners.

 

Add more cam. Put a VX on that thing and you'll be down 15hp everywhere except after 8k, IMO.

 

what is your opinion about buddy club iv?

 

The Px is why torque starts starts falling off the way it does and where it does.

 

It's a copy of a copy. I don't like any of their cams. They use profiles that have no business being used on street motors. Clacka-dee-clack, don't come back.

Their marketing should be a clue to you guys.

 

If you look at the pic's of a cut open PX you will see the runner entry is smaller than on exit at the flange where it bolts to the cyl head the length is only a problem when you start getting up in camshaft duration,its a great manifold but needs work on the 2lt engines.I dont understand why people have not tried the new Skunk2 Ultra Street manifold yet on the big cammed 2lt + b series engines.

 

Looking at your graphs you can clearly see you have an exhaust restriction by how unstable the graph is with the exhaust on and how smooth it is with the exhaust off even how good the AFR's smooth out once the exhaust is off.Keep at it there is still good gains to be had with more R&D

 

Port that performer x and shorten the runners.
But most important is to get some quality Headwork for the lift of the cams.

 

I've actually seen big gains from the Ultra street against the VictorX on a 2L Uncle Dave

 

Thats good it would be nice to see some results posted up,I have talked to Brian@Skunk alot about this.

 

exactly. he has a wonderful powerband. **** if i made 250 at 7500 rpm, i'd just get a gsr trans and shift around 7800. no need to shift high if you dont need to.

 

the OP should just get bigger cams and at the most open the inlet of the manifold to 70mm and use 70mm throttle body. shortening the runners move the powerband to the right and he will lose that pretty torque curve:-)

 

lol 250? i might be looking at a different pic, but i only see 213...

 

Damn my bad lol. Thanks Calvin. 213 is what I meant.

 

hahaha np

i just thought maybe there was an updated dyno that i didnt catch

 

yeah I would just leave it exactly how it is too, that's an awesome torque curve.
I'd say just get a quality header, and build a full custom 2.5" mandrel bent exhaust, and you should be golden.

changing cams and/or intake manifold will more than likely give you more top end, but will cause a noticeable loss in low and midrange. if you want a drag car, change the cams and intake manifold. if you want a street car, keep those as is.

hell, if it were me, I'd just slap a t3 on it and run 6-10psi. talk about a beast; running equal boost as me that engine setup would probably destroy my car in a race

 

later intake valve closing = more dur. = bigger cam

would help indeed, the torque numbers matches the whp so i guess the exhaust isnt too overly restricted, although the 2nd dynosheet has some wavy torque curve

but i think with the length of the perX runners, your peak would be where it's at...
a bigger cam might just extend/flatten that peak a little longer maybe thats wat the OP likes maybe

that is.. without shortening it *runners and porting

as ive seen a few with a wee bit higher numbers with an unmodded perfX but the peak is right about where yours is,

someone correct me if im wrong

 

OP, what cam choices have you looked at yet?