jerod187

hey guys i did a HCI swap i put the GT40 intake on with some 69 heads that have stiff valve springs, 1.9 and 1.6 valves , roller rockers and a holley cam with these specs

dvertised Duration (degrees) 276 280

Duration @ 0.050” (degrees 221 223

Valve Lift (inches) 0.509 0.509

Lobe Separation Angle (degrees) 112


but when ever im at like 20k or so it like bucks and chugs and its smoking a bit and such, So i was reading and people say u need a tune well we put my friends A/F reader thing on the exhaust and at idle it was arounr 50 and then at like 3-4k rpm it went right to about 15-16

so what kinda of tune do i need?

irish1

Couple things I spotted in your post had me curious:

1. what do you mean by "stiff" valve springs? they are either suitable for your cam or they are not.

2. by "20k" do you mean 2000 rpm?

3. simply put, you have parts on your car which enable it to use more fuel and air then the stock ecu's parameters support. You need to either buy the equipment for around 8-900, or pay someone to tune it for you. What I did is buy the stuff, learned how to use it, tuned my car and then sold it(have not actually sold it but you get the idea).

Some things which can mess up your setup that you did not mention in your post:

injector size and is it matched to MAF

fuel pressure

timing

with an A/F of 50 I wonder what your spark plugs look like.

The tune will consist of you telling your car what you have, for example if you are stroked you are not 302 CI anymore, setting break point, maf transfer etc so that in a nutshell, you are making the most out of what you have as opposed to trying to run on stock values.

Hope my ramble made sense!

Matt

jerod187

ok perfect and i meant like 20 kilometers a hour, so were would i take it to get tuned and whats the average cost of this?

irish1

Usually there will be a local dyno and tuners who works out of there, ask around in your neck of the woods for the local ford tuning guru. I've been quoted as little as 400 for a tune and as high as 750.

Matt

jerod187

oo that is a lil expensive

Joel5.0

An EFI engine setup with those specs/components shouldn't "behave" like that, even w/out a custom tune.... BTSTDT.... the EEC should be able to adjust itself within its capabilities w/out those symptoms you describe. Suggest to start with the DIY KOEO/KOER self tests, check fuel pressure, check engine vacuum engine idling and LUK.

aode08

hi jeremy


this is not enough info for your problem



whats the year make model and engine?


are you using a flat tappet cam? or hydraulic roller?

roller rockers or stock?