QV/Anniversary Power Potential

As the subject says, what kind of power can you get out of a QV injected car or an anniversary without going crazy? Can you change the cams and do some head work along with a set of headers and an exhaust change and get 500hp at the flywheel? More, less or what?

interesting question. The engine is limited by the bosch CIS FI. This is a pretty reliable system, but it is 80's technology (technically it is called a velocity/density FI system). This means it isn't tuneable, i.e. a modern computer system uses multiple variables to index into a load table. It is also restrictive because the mechanical fuel distributor uses a pressure plate to measure velocity, so the fuel pressure is proportional to the deflection of the plate. The air induction is convoluted as hell. The injectors are also on 100% of the time. Timed injection is more efficient. Those are some of the issues with this system. It is fine for 80's econo boxes, but not at all meant for a fire snorting v12 exotic. I think you may get some gains just by switching out the very bad log style manifold. Beyond that I just don't see much, certainly not even close to 500hp, maybe 420-430hp. This is just my gut talking.

 

For reference, my car has motec EFI (among other mods) and delivers 500hp. Don't bother with serious mods on a FI QV unless you are willing to scrap the bosch EFI. This is not to say a factory FI QV isn't a sweet car....it is! its just not a good platform for mild mods, which I think was the heart of your question.

you say 420-430, didn't they come with this HP stock? How much does it cost to go with another fuel injection system? We are talking thousands of dollars I assume?

 

interesting question. The engine is limited by the bosch CIS FI. This is a pretty reliable system, but it is 80's technology (technically it is called a velocity/density FI system). This means it isn't tuneable, i.e. a modern computer system uses multiple variables to index into a load table. It is also restrictive because the mechanical fuel distributor uses a pressure plate to measure velocity, so the fuel pressure is proportional to the deflection of the plate. The air induction is convoluted as hell. The injectors are also on 100% of the time. Timed injection is more efficient. Those are some of the issues with this system. It is fine for 80's econo boxes, but not at all meant for a fire snorting v12 exotic. I think you may get some gains just by switching out the very bad log style manifold. Beyond that I just don't see much, certainly not even close to 500hp, maybe 420-430hp. This is just my gut talking.

 

For reference, my car has motec EFI (among other mods) and delivers 500hp. Don't bother with serious mods on a FI QV unless you are willing to scrap the bosch EFI. This is not to say a factory FI QV isn't a sweet car....it is! its just not a good platform for mild mods, which I think was the heart of your question.

In my opinion the motor is induction limited. I came across this.....Kreissieg has an exhaust for the QV and posted a dyno sheet (the only one I've ever seen of a factory FI car for that matter)

http://www.kreissieg-usa.com/images/produc...ct/lamcf6_L.jpg

so about 20hp gain, or 7%. Pretty good. I would trust these numbers more than the factory, aka ideal, numbers. The FI 5.2L probably makes 420hp, on an engine dyno, with no alternator, ideal atmospheric etc....

 

an aftermarket EFI is 5 figures, and is tricky. A motec sytem is 5 figures just for the parts. There are cheaper systems out there. And you get what you pay for.

I had read somewhere, I think it was on here, about a car that is an FI QV that has the cams and such from the downdraft motor installed. If what you are telling me is true, they must have done some other work, but I believe they didn't switch fuel injection systems.

 

In my opinion the motor is induction limited. I came across this.....Kreissieg has an exhaust for the QV and posted a dyno sheet (the only one I've ever seen of a factory FI car for that matter)

http://www.kreissieg-usa.com/images/produc...ct/lamcf6_L.jpg

so about 20hp gain, or 7%. Pretty good. I would trust these numbers more than the factory, aka ideal, numbers. The FI 5.2L probably makes 420hp, on an engine dyno, with no alternator, ideal atmospheric etc....

 

an aftermarket EFI is 5 figures, and is tricky. A motec sytem is 5 figures just for the parts. There are cheaper systems out there. And you get what you pay for.

downdraft cams on a FI motor? intake runner lengths are completely different. seems like a bad idea to me.

This is what makes the downdraft engine so fabulous..... higher compression pistons, different cams, and exhaust headers instead of manifolds. The induction manifolds and the path the air takes through the carbs are a big part of it as well.

 

SuperX's Countach is a bad ass SOB...... you'd have to do a lot of work to match that thing.

Hp figures for all early Italian cars, not just Lambo, but Ferrari too, are all on the very optimistic side. Id say the U.S. Qv makes about 375hp, and about 300rwhp in stock form.

yeah, the downdraft engine is real old school. just awesome, and the last of an era. I would really like to see the torque curve for that engine.

 

no doubt there was optimism, or more accurately, i think they measured under very controlled and optimistic circumstances. Kind of like the "gross" hp specs of the 60's. Still, I wager a trimmed and dialed in downdraft will deliver 450hp, or 375 at the wheels

yeah, the downdraft engine is real old school. just awesome, and the last of an era. I would really like to see the torque curve for that engine.

 

no doubt there was optimism, or more accurately, i think they measured under very controlled and optimistic circumstances. Kind of like the "net" hp specs of the 60's. Still, I wager a trimmed and dialed in downdraft will deliver 450hp, or 375 at the wheels

Yes, no doubt a carbed car in perfect tune will make more power. For the U.S. F.I cars, best thing you can do is dump the CIS.

http://www.drautos.com/search/srDetails.as...6-FE8EA6259EB6}

 

here is the link to the car that says it has the euro cam, pistons, headers, etc.

 

What do you make of it?

I built that car in the link above. Very strong car. In planning the project I had some concerns in what Dennis had mentioned about runner lengths. The Euro cam has more duration, a little more lift and is ground on a 106 lobe seperation. Maybe not the best choice in cams but there are not a lot of cam choices available. Cams can be custom ground but at quit an expense.

I would like to see a motec system installed in that black car. All the benifits Dennis spoke of in an electronic application are fact.

On the other hand I'm old school and LOVE :heart: :heart: down and dirty carbs.

sweet car. Also there is a blk on white listed on ebay.

 

Web cam in riverside CA can do the cams. They know lamborghini and can do whatever you want or help you design a cam. They the cams in my car. I recall it was pretty reasonable.

I built that car in the link above. Very strong car. In planning the project I had some concerns in what Dennis had mentioned about runner lengths. The Euro cam has more duration, a little more lift and is ground on a 106 lobe seperation. Maybe not the best choice in cams but there are not a lot of cam choices available. Cams can be custom ground but at quit an expense.  

I would like to see a motec system installed in that black car. All the benifits Dennis spoke of in an electronic application are fact.

On the other hand I'm old school and LOVE :heart:  :heart: down and dirty carbs.

 

but what about what superx said about how the fuel injection system can't handle the mods? is the fuel injection stock? What kind of power is that car making?

this may help you gain some perspective.

 

a stock FI QV will outperform any 2valve car.

a downdraft engine is highest performing factory countach.

 

Modern FI is vastly superior to carbuerators. Install a motec to unleash the full potential of the QV. There's nothing liked carb'ed engine though. I'd feel lucky just to have a 2v sidedraft. The car i'd stay away from is the injected 2valve. That is a cobbled together hack.

SuperX, what do you figure the guy who built your car had in it?

all work totalled around 80k. It was darn close to a complete resto

all work totalled around 80k. It was darn close to a complete resto

 

Does that include the car?

no. not sure what he paid for the car. I think he was the original owner. He had a haltech EFI put on in the 90's. Then the throttle cable stuck at WOT. pistons bent some exhaust valves. The repairs evolved into a resto with motec upgrade. Then for some reason he lost intrest in the car.

Then for some reason he lost intrest in the car.

 

Thank god for that!

yup! call me the problem solver

I understand all of this, i'm just trying to shed some light on the fuel injection situation. All of that engine work to an injected QV seems to say it isn't running right or the injection system can handle it. Also, can't you add larger injectors to the car and solve the problem that way?

 

this may help you gain some perspective.

 

a stock FI QV will outperform any 2valve car.

a downdraft engine is highest performing factory countach.

 

Modern FI is vastly superior to carbuerators. Install a motec to unleash the full potential of the QV. There's nothing liked carb'ed engine though. I'd feel lucky just to have a 2v sidedraft. The car i'd stay away from is the injected 2valve. That is a cobbled together hack.

i'm not sure what problem your trying to solve. as for the bigger injector comment, no. For NA applications the injectors are sized based on the displacement and VE. Those things do not change.

i'm not sure what problem your trying to solve. as for the bigger injector comment, no. For NA applications the injectors are sized based on the displacement and VE. Those things do not change.

 

I'm just trying to figure out how this car that mike built with the factory fuel injection is handling the euro cams and pistons and such when it was stated earlier that the fuel injection system would have to change in order to add those parts.

:roll: at the risk of sounding short, why don't you call the owner and ask him? Where is it stated the CIS had to be changed to use those parts? Sure, to make serious HP over stock, the CIS has to be upgraded. And Mike gave some detailed info on the car. very nice of him. I think you are making this difficult? My advice is simple...find a sidedraft (i.e. non injected) or any QV. These are the cars to own.