What will a stock 1.7 produce in H.P.with the following.

Progressive 32/36

Weber 40's

D-Jet F.I.

not answering your question exactly
but its more about throttle response than actual HP numbers


for example
a giant set of 48IDA carbs might actually flow the most air and on a dyno at 7K might show the most hp...
but they won't be driveable below 6K

the progressive carb also isn't very smooth when the fuel falls out of suspension in the intake runners causing rich and lean moments..

so its more than just HP unless you are racing and have a very narrow range of 1000rpm or less that you are trying to get it to function within.



you can make your question more specific
what are you trying to do?
are you asking which induction to use on a stock 1.7 with stock everything else including heads, compression, cams, and exhaust?

then DJet is the answer

brant

Assuming they could all be tuned perfectly, about the same.

HP is made in displacement, heads (valves, chamber shape and size, etc), compression ratio, camshaft. HP is unlocked when there is a restriction in the intake/exhaust that gets removed. But if the intake is capable of more than the peak engine HP (1.7 with 40IDFs) then it won't make more power. Your intake is larger than your engine.

The only way to really make a 1.7 produce more HP is forced induction.

Ask him how he knows...

Thanks Brant, I understand that better flowing heads and differnet cam and larger displacement make more HP but I always heard that fuel delivery can also give you more horsepower. I am not trying to change anything on my current engine and was just wondering if fuel systems can actually incease horsepower on a stock engine.

Gasoline combustion is based on a critical mixture of oxygen and fuel. Too far in either direction (rich/lean) will drop off power. If you do the math, it's 14.7 parts air to 1 part fuel. But since engines aren't math problems, often WOT power pulls perform better around 12:1 or more. But in those cases it's technically incorrect to say that more fuel is making more power. More fuel is overcoming the inadequacy/irregularity of the intake and fuel delivery systems.

The real answer is one of those frustratingly vague responses. Peak horsepower is created with just enough fuel. No more. No less.

A progressive single carb gives you one fuel adjustment for the whole motor. So it's wrong most of the time. Kind of like this...
Click to view attachment

A dual carb setup give you one fuel adjustment per cylinder. So it's a little more right, more of the time. Kind of like this...
Click to view attachment

A D-Jet fuel setup is even more right, even more of the time. Kind of like this...
Click to view attachment

A modern, dyne tuned, digital fuel injection system with lots of fuel map resolution is going to be even more right. Kind of like this...
Click to view attachment

Ronnie,

I would guess... that a set of duel 34's, or duel 40 carbs would slightly improve the horsepower on a stock motor.

it would also change the intake sound/noise and be louder and "sound" faster

it might improve throttle response if the jetting was dialed in

but the trade-off would be: harder to start and a loss of MPG
if dialed in for midrange, the bottom end would not be better than DJet
if dialed in for low rpm, the top end will not improve over DJet

brant

Great analogy!

Now ask about HP differences with various exhaust options
Or, use "search" and read up on the tons of great info stored at 914world

I want a turbo!

Thanks all for the lesson. Never can learn to much when it comes to these engines.

Your FI 1.7 produced 79 Hp, new. I think mine is pumping out 78