Boosted Z6 w/Built Head, Power Dies After VTEC Engages
 

I got a 94 Civic DX Hatch
p28 ECU (ofcourse
Greddy SOHC Turbo Kit (15g)
Intercooler
Gude Built Head:
port & polished
valves
springs
retainers
camshaft

adjustable cam gear (set at 0)
dsm 450cc injectors
VAFC II
greddy sp catback
stock greddy downpipe (could be part of the issue)
msd ignition w/blaster coil

Dist. is retarded all the way

cars moves pretty well from the get go, but the moment Vtec Engages which is around 5200 the car feels like it just loses power all and all like the turbo just dissapears.

Not sure the proper way to test of Vtec is engaging or what. The dial changes color on the VAFC when Vtec Engages, but i'm not sure what else could be going on here. Boosting 6psi so the turbo should not be topping out really granted it is a small turbo.

Any suggestions as to what could be going on here?

I am also running a stock cat . . . . any and all suggestions are welcome.

Re: Boosted Z6 w/Built Head, Power Dies After VTEC Engages
 

why is the dizzy retarded all the way?

Re: Boosted Z6 w/Built Head, Power Dies After VTEC Engages
 

I just thought it was safe, but I guess that by doing so i'm loosing a lot of power. What would u suggest?

Re: Boosted Z6 w/Built Head, Power Dies After VTEC Engages
 

I am no turbo guru but I would suggest selling the VFAC II on Egay and go Uberdata! Change your dizzy back to stock and troubleshoot from there. Projecteg does the ecu's for cheap!

Re: Boosted Z6 w/Built Head, Power Dies After VTEC Engages
 

very understandable. I ran uberdata and made 350hp on my LS motor running 14psi. I had uberdata on my car but my ECU crapped out which is why I was forced to buy yhe VAFC to make my car drivable because I refused to drive with a FMU on my car. So I need to kinda address this issue and fix my ecu to run uberdata again

Re: Boosted Z6 w/Built Head, Power Dies After VTEC Engages
 

TTT

Re: Boosted Z6 w/Built Head, Power Dies After VTEC Engages
 

Get another ECU if you have to but troubleshooting with the VFAC is gonna own you!

Re: Boosted Z6 w/Built Head, Power Dies After VTEC Engages
 

they are selling a kit in classifeds, u get a ecu, chipped, basemaps, and a buner, sell that hack and use the money or uberdata

Re: Boosted Z6 w/Built Head, Power Dies After VTEC Engages
 

The thing is I don't believe it's the hack that is causing my power to be lost when Vtec Engages . . . . so selling the VAFC II is not going to solve my problems. I know how could Uberdata is because I ran it on my self tuned 350whp Built LS Motor and everything was good until my car was stolen. I'm pretty sure i'll encounter the same problem running uberdata, so I first need to resolve this issue =)

I have 4 spare chips, I got the moates burner, I got a chipped p28 ecu just not sure if it works yet since I have not tested it out since my friend re-soldered it.

Does anyone have any idea as to what could cause that power loss?

SMall Greddy Downpipe with a Cat Converter? Perhaps creating to much back pressure?
Timing?
Valves?
Vtec Not Engaging?

Re: Boosted Z6 w/Built Head, Power Dies After VTEC Engages
 

Here is the only CAM that I have found that GUDE makes for my particular application:

PART NO: HCCS14
DESCRIPTION: Excellent with NOS.
POWER BAND 2000 RPM. to 8500 RPM.
IDLE: Fair
SPECIFICATIONS:


Intake Lift - .397 Duration - 261
Exhaust Lift - .407 Duration - 228

Is that the specs of a NA cam or turbo friendly cam? Here is some CROWER Specs for a turbo cam just to compare:



Stage 1 - Features far more agressive ramp rate then stock with added duration.
Excellent for turbo and nitrous.
Idle to 7200+ rpm.

Advertised Duration: 292 / 302
Duration @ .050": 228 / 208
Gross Lift w/ 1.6 int /1.8 ext 406 / 385


What do you guys think?

Re: Boosted Z6 w/Built Head, Power Dies After VTEC Engages
 

Bump Need Help here Guys

Re: Boosted Z6 w/Built Head, Power Dies After VTEC Engages
 

fully retarded distributor, fully retarded move. :-* just so you know.

Re: Boosted Z6 w/Built Head, Power Dies After VTEC Engages
 

try retarding the dizzy about 3-4 degrees and go from there..

Re: Boosted Z6 w/Built Head, Power Dies After VTEC Engages
 

are you getting a CEL at all when you go into vtec? i also have a gude head on my z6 although im running the stck z6 cam. have you done a valve adjust on it? i think gudes specs are different for valve lash than stock. it really could be your valves. when the valve lash isnt right it causes all kinds of problems. get a timing light on it also make sure that is correct also and then try playin with your cam gear a bit. when i put the stock cam in my gude head i had to advance the cam 6 drgrees just to get it back to stock timing. ran like ---- until i did that.

Re: Boosted Z6 w/Built Head, Power Dies After VTEC Engages
 

you are losing power from the retarded distributor. you have a chipped p28 and tools to tune the car with uberdata, you're an idiot for not doing so. i swear to god, my buddy was having the same exact problem with the hack on his z6, he had higher comp. so he had to retard the dizzy so he wouldn't get detonation, and the power loss owned his ass. we threw in a chipped p28 with a completely stock basemap, reset the timing, and he about ---- his pants. that's an idiot move running the hack like that and just guessing retarding the dizzy all the way will make things safe, hell, your egt's are prolly throught the roof!

Re: Boosted Z6 w/Built Head, Power Dies After VTEC Engages
 

Actually my EGT's arn't through the roof because I tuned it with my wideband =) I hear what you are saying though in regards to the ECU. I just have not had the time to test if it is good or not. I think some of the solder cracked and my friend tried to de-solder it and re solder it. The only reason why I even baught the VAFC was to get my car running so I could go back to work. It's a long story, but to make it short. I had a 92 civic ex 4 door for the past few years. Finally went B series last november, baught all my new turbo goodies. Self tuned the car at 1 bar making 350whp on my ls motor, then some little fags decided to jack the car and strip it, so I had to wait 4ever and insurance gave me a lame cashout which is why I baught this hatch.

When I first got the hatch the owner told me the o2 sensor was bad but when I drove it I knew he was wrong. It had a FMU, MSD Inline Fuel Pump and ran kinda shitty. I tossed in my old ls stock injecors and the car ran excellent come to find an injector had failed. SO I took out the FMU and inline and dropped in my walboro, and my chipped p28 then after partial tuning come to find a solid CEL couldn't get my car to start, we tried everything so that's when I ordered the VAFC just so I could drive my car. Trust me i'm def. going back to uberdata.

So what's the bottom line sound like here, timing issue? Adjusting the valves today, prob. the usual maintenance change oil, spark plugs, and checking timing. Anything else?

Re: Boosted Z6 w/Built Head, Power Dies After VTEC Engages
 

no CEL at all. Hopefully I can find the specs for the GUDE head some place but not sure I will be able to.

Re: Boosted Z6 w/Built Head, Power Dies After VTEC Engages
 

your egt's don't have anything to do with your 'wideband', you tune your a/f ratio with a wideband, you monitor/tune your timing with an egt, the more retarded, the hotter your egt's are b/c the gas is escaping the combustion chamber and exploding in your manifold, so yes, retarded distributor all the way, equals high egt's ;) as far as what to do with the car, some people have really good luck with the afc's, some people can never get them to run right as long as they live, i'm sure the problem is in your fuel/timing

Re: Boosted Z6 w/Built Head, Power Dies After VTEC Engages
 

so people don't get the wrong idea here . . . . . since my dist. was retarded all the way, I advanced it 1/4 of the way back so now it's sitting right btween stock/retarded. Low end pulls a little better, better throttle responce, but still tapers off when vtec engages.

We checked my valves and only a couple were out of spec a tad. Now when valves tick that's a sign of them being to loose or to tight? I would like to re check my valves. I am trying to find some specs that will benifit me since that damn cam that's in my motor has such a high lift and duration. Thinking of maybe taking the cam out and running a stock cam if I can't find any specs to benifit me with the camshaft.

The VAFC II seems a bit different from the first gen. It's got a couple different VTEC settings that i'm trying to read up on to see if that could help my problem out. It's really hard to tell if VTEC is engaging though. I've never owned a DOHC VTEC Turbo car, but all the times I ran all motor with my SOHC Vtec u can tell when Vtec engages, but when you enter boost you can't hear the crossover anymore, so i'm kinda boggled.

We will be testing the ECU today, and if that works i'm moving back over to Uberdata or CROME, but I would still like to address this issue anyways incase the ECU fails.

Re: Boosted Z6 w/Built Head, Power Dies After VTEC Engages
 

if you've got the distributor in a decent place as far as timing goes, and you're dropping power at the vtec crossover, id say one of two things

bad afc setting or wiring

or

just not engaging at all, which could lead back to the AFC again.

Re: Boosted Z6 w/Built Head, Power Dies After VTEC Engages
 

most people engage vtec at around 4200-4800 on turbo vehicles. the earlier crossover is helpful to it since it makes more torque earlier in the powerband, it doesn't bog it down like a n/a engine would.