losing power with P&P on a Z6

[BoogieDown]

I have an 88DX with a Z6 swap. I had my head Ported by a local shop and after I put it on it felt slower.

The head has been milled about .015" w/Stock cam My mods are ebay header,2.25" exhaust , Short ram intake, Ign timing is stock at 16*. My best 1/8 is 10.2 at 72mph w/ 2.5 60'

I seems sluggish till about 5500 where it seemed to pick up. Before the P&P it seemed to have more power thruout the entire power band.

 

[handlebarsfsr]

whoever ported the head took too much material off, and hogged out the ports.

 

[BoogieDown]

So I should get a new head or put a huge turbo on it? lol

 

[handlebarsfsr]

Quoted post[/post]]
So I should get a new head or put a huge turbo on it? lol

huge turbo wont fix the problem. either get really high compression pistons, and big cams to go with it, or junk the head and punch the guy who ported it. did he ask for specifics about your setup, goals, build, etc before he ported it, or did he just take the head and your money and give you a "modified" head package?

 

[BoogieDown]

I asked for a mild port job ,nothing fancy. Though a big turbo would take advantage of the larger ports, I don't really know too much about turbos.
How much compression, 12:1? Stage2 cam or bigger?

 

[Cashizslick]

Im guessing 11:1 would work since you want to retain this car as a streetable vehicle.

Cam it with something decent . . . i thought JUN made a good cam for the z6 (or mabye it was the y8?)

 

[hcivic.com]

get the flow bench sheet before and after from the guy post them and it will beter help us. And if he did not use a flow bench get your money back

 

[BoogieDown]

Quoted post[/post]]
get the flow bench sheet before and after from the guy post them and it will beter help us. And if he did not use a flow bench get your money back

no flow bench files. Its easier said than done to just go and get my money back. Probably pick up another Z6 head. Flow bench the old head and if its ok build a high comp mini-me. I have a spare D15B8

 

[brian11to1]

did you adjust for the millin in timing?

if you remove a lot of material, then the angle changes and the timing is different. i believe it advances the timing, it may also retard it. either way, make sure hte timing is set to 0, factory specs.

 

[BoogieDown]

Quoted post[/post]]
did you adjust for the millin in timing?

if you remove a lot of material, then the angle changes and the timing is different. i believe it advances the timing, it may also retard it. either way, make sure hte timing is set to 0, factory specs.

not sure if your talking about cam timing or ign timing. Ign timeing is set at stock 16*. Cam timing is retarded about 1-2* from milling the head

 

[brian11to1]

Quoted post[/post]]

Quoted post[/post]]
did you adjust for the millin in timing?

if you remove a lot of material, then the angle changes and the timing is different. i believe it advances the timing, it may also retard it. either way, make sure hte timing is set to 0, factory specs.

not sure if your talking about cam timing or ign timing. Ign timeing is set at stock 16*. Cam timing is retarded about 1-2* from milling the head

i was refering to cam timing.

then you covered what i was talking about.

 

[BoogieDown]

I haven't corrected this yet, still need to get a cam gear.

 

[civicious]

My vote goes to 'punch the guy who ported it'

 

[BoogieDown]

Quoted post[/post]]
My vote goes to 'punch the guy who ported it'

Well action was taken but nothing to harm him. Hes just gonna be kinda sad for awile

 

[rexsk8er]

Quoted post[/post]]
It's probably because you put a ported head on an otherwise stock motor. It's like putting a Skunk2 IM on a stock Z6, you'll actually lose power because you don't have the mods to support it.

And your cam is 1.2 degrees retarded for every .01" taken off. Retarding the cam timing takes power from the bottom and moves it up top.

Yeah, thats true. its like a pump, for air. your stock manifold can only flow so much, and generally honda doesnt over build one part over any other. so in order to take advantage of the larger flow in the head, alot of stuff has to be done like short runners that take effect of air resonation (air boucning back and forth in the I/M and hitting the valves at the right as they open), at the rpms your cams ideal for. say your cam works best from 6500-8000 rpms, youll need short large dia. runners. basically you need to know your cams specs, all the flow data of the head, and than you can build an intake manifold or buy one. exhuast is similar, its pointless to have one mod. its only as weak as it weakest part.

 

[BoogieDown]

Very true. It sux when you ask advice from the wrong people and you don't know anybetter(no1 on here) I was going to buy a stage2 crower cam, spring kit and an adj cam gear. Then get the Edelbrock performer X IM (3k-7800rpm). But if all my power is gonna be 6k+ It won't be very practial for me as a daliy driven car.

Quoted post[/post]]

Quoted post[/post]]
It's probably because you put a ported head on an otherwise stock motor. It's like putting a Skunk2 IM on a stock Z6, you'll actually lose power because you don't have the mods to support it.

And your cam is 1.2 degrees retarded for every .01" taken off. Retarding the cam timing takes power from the bottom and moves it up top.

Yeah, thats true. its like a pump, for air. your stock manifold can only flow so much, and generally honda doesnt over build one part over any other. so in order to take advantage of the larger flow in the head, alot of stuff has to be done like short runners that take effect of air resonation (air boucning back and forth in the I/M and hitting the valves at the right as they open), at the rpms your cams ideal for. say your cam works best from 6500-8000 rpms, youll need short large dia. runners. basically you need to know your cams specs, all the flow data of the head, and than you can build an intake manifold or buy one. exhuast is similar, its pointless to have one mod. its only as weak as it weakest part.