I have been searching across the forums and have found an interesting lack of dynos for naturally aspirated spiders. In GCs book he says a 9.6:1 compression 2.0l can generate 155 bhp @ 6300 with dual weber 45 dcoes.
Does this seem a little high?
The goal for my engine is to get 120hp at the wheels with a strong torque band. Can this be achieved with 9.8:1 pistons and programmable fuel injections? It would be nice to see what other people have done and their similiar numbers.
NA Fiat Power Curves
-
Danno
it sounds doable to me. I know it's a useless comparison, but my aerio has a 2.0L and gets similar compression (9s) and puts out stock 145hp at the crank. Granted it's a fuel injected coil-over ignition system and with all the cool ecu technology they have today. but still just shows that and engine of that size with good compression, fuel, fire, and air can run easily that high.
-
mdrburchette
- Posts: 5754
- Joined: Wed Jan 25, 2006 5:49 am
- Your car is a: 1972 Fiat 124 Sport
- Location: Winston-Salem, NC
-
Joe Clemente
- Posts: 151
- Joined: Wed Jan 25, 2006 1:35 am
- Location: Vancouver, B.C. CANADA
120 @ the wheels? That is approx 140 at the crank James. Completely doable with that combination. It really wouldn't require much, just a few bolt ons.
FWIW, my own 2L made over 160hp with 9.8:1, 40-80s and 44 IDFs.
Keep in mind that any significant power gains above and beyond will come from the head, that's where it is all made, not just in the bottom end . So that means correct cams, valve sizing, port and throat work.
FWIW, my own 2L made over 160hp with 9.8:1, 40-80s and 44 IDFs.
Keep in mind that any significant power gains above and beyond will come from the head, that's where it is all made, not just in the bottom end . So that means correct cams, valve sizing, port and throat work.
-
Hjulen
-
Joe Clemente
- Posts: 151
- Joined: Wed Jan 25, 2006 1:35 am
- Location: Vancouver, B.C. CANADA
Big valves are always beneficial but you don't have to go that far. Even stock sizes will work well if you perform a proper valve job. The seat, throat and back of the valve will be where you'll want to concentrate.
Porting should not be excessive. Don't hog them out.
I've seen too much of that mentality, at times applied even by self-proclaimed "specialists" resulting at best in reduced intake velocity and poor drivability. Worse, it can end up in catastrophic f***k-ups where the whole head has to be scrapped. If you DIY, follow the GC manual as it is pretty safe. If you don't and need a recommendation, I'll be happy to point you in the right direction.
Cam choice is also important. more lift, more oomph.. Again, it is all a part of the head. That's where it'll be made.
Porting should not be excessive. Don't hog them out.
I've seen too much of that mentality, at times applied even by self-proclaimed "specialists" resulting at best in reduced intake velocity and poor drivability. Worse, it can end up in catastrophic f***k-ups where the whole head has to be scrapped. If you DIY, follow the GC manual as it is pretty safe. If you don't and need a recommendation, I'll be happy to point you in the right direction.Cam choice is also important. more lift, more oomph.. Again, it is all a part of the head. That's where it'll be made.
-
bandit
The DCOE's add a bit more power just from the flow to give
an edge over the down drafts and that 155 mark isn't all that
hard to do . going from 9 to 1 to a 10 to 1 compression ratio
is only about 5 HP gain .
Like Joe was talking about the power increase will be in the
head, how well it flows and how it is feed .
Dan
an edge over the down drafts and that 155 mark isn't all that
hard to do . going from 9 to 1 to a 10 to 1 compression ratio
is only about 5 HP gain .
Like Joe was talking about the power increase will be in the
head, how well it flows and how it is feed .
Dan
-
Hjulen
I think I am just surprised that I have not caught on to the importance of head design and efficiency in engine power. But why wouldn't that make sense? Maybe what amazing me most is how much of a difference it should actually make...but again its all logical according to theory.
Better flow...better cylinder filling...more air...more fuel...more power...more go...
I would love it if you could point me in the right direction Joe, as a sturdy machine shop is hard to find.
The next question I suppose now is how good is the stock FI manifold on the spider? Individual throttle bodies are sweet, and I hope to be able to do such a mod in the future, but I wonder if building a custom intake manifold with a single TB would be more beneficial.
Better flow...better cylinder filling...more air...more fuel...more power...more go...
I would love it if you could point me in the right direction Joe, as a sturdy machine shop is hard to find.
The next question I suppose now is how good is the stock FI manifold on the spider? Individual throttle bodies are sweet, and I hope to be able to do such a mod in the future, but I wonder if building a custom intake manifold with a single TB would be more beneficial.
-
Joe Clemente
- Posts: 151
- Joined: Wed Jan 25, 2006 1:35 am
- Location: Vancouver, B.C. CANADA
James,
I'll PM you with a couple of sources in the US you should consider. I am not personally familiar with too many choices in Florida except for a couple of bad ones but I can recommend a few people you should consult for services not too far from you.
Manifold question: you mean a stock FI manifold? It's ok but if you are going to use individual TBs then you will have to chop it anyway. The key is the connection between the TB and the manifold itself. That doesn't have to be exotic just tight. Those tube connections we mentioned before will be perfectly functional.
I'll PM you with a couple of sources in the US you should consider. I am not personally familiar with too many choices in Florida except for a couple of bad ones but I can recommend a few people you should consult for services not too far from you.
Manifold question: you mean a stock FI manifold? It's ok but if you are going to use individual TBs then you will have to chop it anyway. The key is the connection between the TB and the manifold itself. That doesn't have to be exotic just tight. Those tube connections we mentioned before will be perfectly functional.
-
Hjulen
I was just eyeballing the manifold when I was home a few weekends ok and it seems to me trying to fit the TBs on the stock one might be difficult because the number 2 and 3 cylinder runners are really close together.
Of course I dont have a spare manifold to actually measure out and play around with.
Of course I dont have a spare manifold to actually measure out and play around with.
-
bandit
I have been looking at the stock FI on My fiat as well and I might
unbolt the top plenum cover and turn it around cut out the factory
TB and bolt on a lager one some where between 50 to 55 mm
and use A Mega FI System but just toying with the ideal so
you herd it here first if some one does it they beterr send me a picture dammit ! cause it was my ideal hehe .
That would be easyer route to take .
I have Modified a few things on my FI already and love the power
from a pretty much stock Fiat FI on A well built engine .
I will go into details another time i am tired and need sleep .
Dan
unbolt the top plenum cover and turn it around cut out the factory
TB and bolt on a lager one some where between 50 to 55 mm
and use A Mega FI System but just toying with the ideal so
you herd it here first if some one does it they beterr send me a picture dammit ! cause it was my ideal hehe .
That would be easyer route to take .
I have Modified a few things on my FI already and love the power
from a pretty much stock Fiat FI on A well built engine .
I will go into details another time i am tired and need sleep .
Dan
-
Wayne Mausbach
NA Horse Power
Dan,
I also have been looking for NA hp dyno runs. I'm currently putting a 1800 head with big valves on my FI spider. I took the FI manifold and matched the head and gaskets. I also have a bigger BMW AFM. There was a lot of metal removed as the manifold really had small openings. I didn't touch the head but the gasket was also a poor fit.
As soon as I put it together I plan to get a dyno run as I plan to document each upgrade. I would like to see what I can get out of a stock FI manifold.
The next step will be put in 9.8 pistons when I rebuild the engine.
Ciao
Wayne in Houston
81 Spider (Daily Driver)
72 Spider (Volumex Project)
69 Coupe (Old SCCA race car)
I also have been looking for NA hp dyno runs. I'm currently putting a 1800 head with big valves on my FI spider. I took the FI manifold and matched the head and gaskets. I also have a bigger BMW AFM. There was a lot of metal removed as the manifold really had small openings. I didn't touch the head but the gasket was also a poor fit.
As soon as I put it together I plan to get a dyno run as I plan to document each upgrade. I would like to see what I can get out of a stock FI manifold.
The next step will be put in 9.8 pistons when I rebuild the engine.
Ciao
Wayne in Houston
81 Spider (Daily Driver)
72 Spider (Volumex Project)
69 Coupe (Old SCCA race car)
-
Hjulen
-
bandit
The Fiat FI Manifold runners are real good but the plenum is on the
small size plus runners 2 n 3 have a lifted ports or extended so
what was done to my manifold extend all 4 to the same length adding
about 3/4 of an inch in length but keeping the port size the same .
The TB was ported some and polished and running a K&N filter I'm
happy with the performance feels as good as 40 IDF's on a mild
Engine with out the adjusting from time to time and it starts right
up in the mornings .
Dan
small size plus runners 2 n 3 have a lifted ports or extended so
what was done to my manifold extend all 4 to the same length adding
about 3/4 of an inch in length but keeping the port size the same .
The TB was ported some and polished and running a K&N filter I'm
happy with the performance feels as good as 40 IDF's on a mild
Engine with out the adjusting from time to time and it starts right
up in the mornings .
Dan