Cascade Crew

blue89 · Posted: Thu Jul 05, 2007 2:43 pm Post subject: Carb cam on EFI setup

Does anyone know what happens when you put a camshaft intended for a carburetor in an engine with FI? What happens when you go vice versa? I would imagine that the FI cam won't work with a carb, but are the overlaps similar enough that it works without problem? May be FI is smart enough to learn the carb cam, but FI has less vacuum and wont' work with carbs?

blue89 · Posted: Thu Jul 05, 2007 3:11 pm Post subject:

The cam in the car is:
ID ED Sep IL EL
Cam in car 206 206 108 .430 .430
Carb cam 204 214 112 .420 .442

Twilightoptics · Posted: Thu Jul 05, 2007 5:13 pm Post subject:

Basically what's going to happen... is your volumetric efficiency is going to be thrown off all over the board. Meaning it's going to change. Now maf cars are better at this than SD. Maf can read the air for the most part and add proper fuel to a point.

SD the map has to be changed or the computer is going to be in a constant state of either adding fuel or subtracting fuel. When this happens, driving cold will suck because there is no correction... so wherever you are lean/rich that normally you'd be close with the stock tune.... you wont be and it will make things rough.

Acceleration enrichment or pump shot will need changes.

That's just the quick quick quick version.

BTW what EFI cam is stock on a 108LSA?

That's more of a carb cam than a 112LSA.

Both of those have minimal overlap so Idle will be okay interms of o2 compensation, but open loop will be off.

rjmcgee · The Hammer Joined: 08 Jan 2004 Posts: 2328

Schultzy89GTA · Posted: Thu Jul 05, 2007 5:54 pm Post subject:

blue89 · Posted: Fri Jul 06, 2007 6:35 am Post subject:

thats a good one Very Happy

Yup, this is for my V6 car. I don't know what the stock spec was. The cam in it right now is not stock. I'm just getting tired of the SD setup on this cam. It sucks. Plus tuning is being a bear. I'm seriously debating about getting rid of the car. Well, parting it out at least. It has been a fun autocross car and a decent fun time, but with an 89 LT1 and an 87 V8 with T5 sitting in the back yard... its just not as fun as it used to be. Not to mention the Lt1 would be a kick in the pants with the V6's 4.11's and disk rear!

I really need to find someone who can help me out. But even then, I'm not expecting to be wow'ed with new found power. I'm just getting frustrated [/rant].

rjmcgee · The Hammer Joined: 08 Jan 2004 Posts: 2328

I can't offer any good advice for the V6, but good luck.

BTW, the 4.10's in the LT1 car would kick ass.

91RSVert · Posted: Fri Jul 06, 2007 7:15 am Post subject:

My v6 was still faster then my v8 Laughing

blue89 · Posted: Fri Jul 06, 2007 8:13 am Post subject:

Ya, but you have some work yet to do to make your vert better. It will get there!

I think I might take it to the dyno guy and get some good wideband o2 readings. Once I get that I can tune or see if I'm way off. I don't have the stuff for datalogging so the o2 is all I have.

I want to drift this car really bad, but it just doesn't have the top end that I need. 30 more hp would be awesome cause the car is almost there. Its underpowered, but right on the edge of enough. Lol, I know it sounds dramatic, but if i could get a little more from it I could pull the car sideways at 50mph in 2nd at 4500-5500rpm. And thats what I need to participate in stadium events. Long high speed sweepers just kill me. Anything under 40 and the car owns, it just starts to loose power at upper RPM's.

83Z28BlackBetty · Posted: Fri Jul 06, 2007 9:19 am Post subject:

what does it have in the way of exhaust? there could be a few extra horses. just a thought

~JAKE

blue89 · Posted: Fri Jul 06, 2007 9:48 am Post subject:

stock manifolds and partial wye, no cat, 3" all the way back with magnaflow single in single out muff. Headers would help I'm sure but I don't think it would help enough.

Sellmanb · Member Joined: 30 Nov 2004 Posts: 727 Location: Tigard, OR

stock manifolds are a huge blockage. 3" exhaust is going to gain you nothing unless you plan on 300-350+ fwhp? 2.5" May be the "sweet spot". I doubt the exhaust would make a 30hp difference in a V6, espescially with an ill-fit cam.

You could always do an LS1 swap, they are lighter than a regular V8, and IIRC weight in at almost the same as an iron V6.... there'd be your power, and power to weight ratio Wink

91RSVert · Posted: Fri Jul 06, 2007 12:56 pm Post subject:

Ive got alot of work left on the vert. You should see the parts collection!! I'm still missing some headers *cough* Laughing

Headers didnt do as much as I thought for the v6. No doubt it gained some. Your v6 is more radical then mine was, so maybe it would help? And I forget what all you had done. P&P, cam, 3.1 with high compression pistons. What else? The 3" exhaust is not really needed untill you get headers. In fact, it may be hurting you. Search on TGO (once search is fixed) and find the threads on "redraif" and her exhaust work. I think most your choke is the intake.

And I told you I would send my cable up for you to scan for a few weeks if you need it. Wedgie time!

90droptoproc · Posted: Tue Jul 10, 2007 2:10 am Post subject:

if you part it out I will smack you Evil or Very Mad

blue89 · Posted: Tue Jul 10, 2007 7:01 am Post subject:

Yessir, sorry sir.

You should see the new Zed 28 rich, it even has one of those car-bur-etors you seem to love so well! (Weber Carter 4bbl (750cfm?), Holley street dominator intake, shorty headers).

90droptoproc · Posted: Wed Jul 11, 2007 1:05 am Post subject:

thats more like it Laughing

I will have to come out there soon, but, with the house I have been quite busy lately