GM 847 Idle + Rev video

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01-06-2004, 06:16 PM

#31

SILVERZZ28

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Location: DAPHNE,AL USA

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atljar

I guess it was really just a question. i did not mean to sound neg.

BTW I have some awesome ported LT1 heads when you get ready

01-06-2004, 06:46 PM

#32

Robert95z

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Join Date: Jan 2002

Location: Houston TX

Posts: 1,001

Quote:

Originally posted by atljar
Thanks Jesse. You installed that pulley yet?

Stock bottom end. Unported heads, not milled, no valve job, never been off the car stock.

Car is everyday driver. Only issue i have with cam is that it surges a tad if you back off the gas quckly at ~1500rpms. As long as you are giving it gas all is well. 24-26mpg on highway with 4.33 gears

Cam pulls 11 inches or so of vacuum. Power brakes werent as good as they were before cam change. I compensated for that with tuning so that the car idles at 1500-1600 when slowing down so that the brakes work fine. Once it comes to complete stop, it idles down to 875.

I see, I've been debating on streetable cams yet wanting to run 11's na... and hell you did it with stock unported heads which is ***in a' sweet!.... As for the surging, if your crusing and the RPMs are at ~1500rpm will it feel/drive any different than driving at ~2500rpm?

As for vacuum, I want to keep power brakes... without getting a tune you got isnt it possible to get a vacuum reserve/booster put in? would that be easier/safer?

Thanks,
Robert

01-06-2004, 09:23 PM

#33

atljar

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Location: Cincinnati, Ohio

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Quote:

Cruising at 1500+ rpms is fine as long as you are on the gas a little. If you back off the gas, the fuel deceleration tables kick in and it cuts the fuel, and in combo with the cam causes it to jump a little. Ive tried playing with the tables to no avail. Only difference cruising higher in the rpm tables is that it wont buck if you get off the gas, and noticable more power at 2500 compared to 1500.

Quote:

As for vacuum, I want to keep power brakes... without getting a tune you got isnt it possible to get a vacuum reserve/booster put in? would that be easier/safer?

Safer, maybe, not easier. Just tell whoever is tuning your car to add a bunch to the IAC vs MPH follower table.

Quote:

Do you think its possible to get rid of all the cam surge with tuning?

Maybe could get a tad better, but not much. I prolly have almost 200 computer flashes on this set-up alone tweaking things.

Quote:

How do you think this cam will run with stockheads and stock 3:42 gearing? Think the cam surge will be more evident or will it be liveable? Thanx!

I would advise 4.10s+ in 6 speed, and 373 in a4. The cam likes to rev, and you need the gears to take advantage of it. Using the stock 3.42s is going to put your highway and street rpms right smack in the middle of where it likes to surge.

01-06-2004, 10:22 PM

#34

lt1camaroman93

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Location: Merrillville, IN

Posts: 936

this thread is helping my hydrolic roller or solid roller cam decision quite a bit.. I need a cam that makes power all the way to 7k and haven't been having luck finding a hr to do it.. looks like i might have to sack up and get a sr

01-06-2004, 10:23 PM

#35

SS MPSTR

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Location: SoCal

Posts: 2,525

Sorry to get off topic, but are you running a stock MAF? Any other tuning issues?
EDIT: saw the MAF. Any issues?

01-06-2004, 10:38 PM

#36

atljar

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Join Date: Feb 2001

Location: Cincinnati, Ohio

Posts: 3,068

Quote:

Originally posted by lt1camaroman93
this thread is helping my hydrolic roller or solid roller cam decision quite a bit.. I need a cam that makes power all the way to 7k and haven't been having luck finding a hr to do it.. looks like i might have to sack up and get a sr

There are plenty of HR cams that will make power up top. Big difference between HR/SR is the ramp rates. A SR will me more driveable most times and have better area under curve.

MAF...that was one of the first mods i ever did to car. No issues at any stage.