Thread: 175WHP 12.5:1 but loosing 20WHP at cam change!

well i had my engine ran up on my local dyno its a dynapack hub dyno

specs

SR16VE ECU With unichipQ for mapping

SR20 4CW crank
DET pulsar rods
N1 psitons uncut
N1 copy cams* set at +5 -5
Fuji header with modified 2.5inch after secondrys 3" decat and cat back
WAI with blox 3" velocity stack

*the cams are copies by a company in the uk called newman.. when i rang him though he said he didnt have the specs and was working blind on the cam centers so they may not be degreed right.. so i had to take them as being okay.

right heres the graphs links for big :-

power and tourqe

http://img.photobucket.com/albums/v355/Drifterx_uk/Silver%20GTi/Photo771.jpg?t=1292435180




AFR

http://img.photobucket.com/albums/v355/Drifterx_uk/Silver%20GTi/Photo773.jpg?t=1292435271



its mega lean below 3K but we couldnt change that with the limited scope of the unichip..


but that doesnt concern me as she pulls strong in the low RPM anyway its the top end and the loss with the cams at switching point.. theres a huge 20BHP loss and rather than a lovely cam change roar theres nothing just a flat noise.. the top end feels abit dull if im honest.

also we couldnt cut the speed limiter out hence it only going to 7866RPM as it was run in 4th gear

any ideas? or am i expecting to much from my settup?

any advice welcome

Set your cams to 0,0

Do you have a copy of your map.?

raise your cam switch point... my guess, is if you were to dyno on just the small cam and then again on just the big the graphs will intersect around 6500 which i think is what everyone means when they say "smooth engaugement" or whatever...

you are running much leaner after the cam engaugement.....

Hmmm.... You may have been better off just getting the real N1s and as Jamie said set them at 0,0. Newman didn't have the actual cam specs and was working blind on the cam centers and those can have eerie results. They may have to be degreed & shimmed and even then may not make as much power as the OEM N1s. Ditto on the copy of your map, timing I assume.

Confirm your centerlines. Switch cams at 6-6.2k. Try a set of n1s the copys may not be as exact as your lead to believe....

And why not just dyno in 3rd to avoid hitting your limiter. Usually do pulls in 3rd on na cars anyways

we went into 3rd on the road for polishing the map up..

i dont have a copy of the map.. as its on a dastec piggy back that are locked by the dealers.. its basically like an emanage plus or minus the ecu outputs at certain peramiters..

im definatly thinking that the cams especially the high lobes arn't degreed correctly..

the reasson i have set it +5 -5 it to increase the overlap to control det as even with the top spec 99 ron pump fuel with 12.5:1 myself and the other cars are getting levels of det.. mine thankfully was minimal because of the overlap..

so the plan for myself will be genuine N1's and moving to a DE loom with nistune and a switching system..

I remember having detonation issues when I had the cams at +5-5 in the day time rush hour traffic with the a/c on or people in the car, and when I reduced the overlap it went away, but then again that was on sr16(non n1) on 20v pistons. I think its the cams and the sr16 program, I ran one at one time and the graph was all choppy I had to retard the distibutor to get it smooth but then it was sluggish at driving.

I may be jumping to conclusions but I think it's the cams. n1 should not be switching over any higher than 5400 rpm's. I have them at 4900-5100rpm's.

GL

Edit nvm

I have found best results on the dyno with switching N1's at 5400 or higher.

It comes down to cam/cam timing. I have seen jumps of 15+hp from going +5,-5 to 0,0. The tune also looks wayy off from the AFR's.

On the dynapacks he should be seeing 205hp+ easily.