Increase Performance?

[mdrburchette]

You got that right, Jeff. A 25% gain is nothing to sneeze at.

[ace124]

Im sure its just a typo Steve but you mean 8.9:1 for the 1438 im sure.

What is the compression on an American model and what is the compression on a 1980 2l European model, stock?

I'm not 100% sure of the federal 124 efi engine spec, but suspect around 8.0 to 8.5:1 and about 100hp if your lucky, by comparison a european 2 litre Argenta EFI was 9.35:1 and 122hp which was the most powerful 2 litre 8 valve EFI NA engine ... the Spyder Europa was about 118hp but had slightly different engine management and 9.2:1.

1438 was 9.8:1, 1608 was 9.8:1 1756 was 9.8: or 9.4:1, 2 litre was 9.0, 9.2 or 9.35:1 in european trim.

SteveC

[fiatfactory]

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[ace124]

My original 1438 dynoed 65RWHP but felt like it had 100 when the revs got up there.

[samthedog]

35hp increase on a 1608 with those mods is pretty optimistic

Maybe I misquoted Jon. Will read some emails from him to see if this is accurate.
The last thing I want is to ding his rep.
Whatever the gain is by doing what he is with my engine will be fine with me.
The guy knows these cars,and these are the largest pistons that will fit this engine.

Sorry if I laid out some bad info.

[mdrburchette]

Not a problem. Most of us know Jon personally and can vouch for his integrity. Just tell him you wish it could be as awesome as Denise's 1608 but you understand that isn't possible.

[puddin]

just wondering -- i know these aren't drag cars (my 78 ran a 19.2, 18.8, 18.72 in the 1/4mile trap speed just of 70mph) but that does seem to be the way to judge outright performance of the engine so:

if 125hp is normally asperated and would cost i guess around $3000 to build and my stock motor is i guess 80-90hp

what would the extra 35 ponnies do in a quater mile == would it even break 16sec before destroying the differential or clutch???

[fiatfactory]

.

[spiderrey]

I think mine is above 125, have not broken a diff yet. I did blow the teeth out of another diff with a stock 2 liter, a set of webers and cheap headers though. Breaking the diff came from poping the clutch to hard, to many times.

[Eastlight]

Probably less expensive to drop in a 350 Chevy engine like one Fiat I saw. Of course that means beefing up the suspension and building an extended front-end but the car will be the fastest Fiat in the neighborhood.

[131]

Probably less expensive to drop in a 350 Chevy engine like one Fiat I saw. Of course that means beefing up the suspension and building an extended front-end but the car will be the fastest Fiat in the neighborhood.

Until you come to the first corner! Then the local kid on the skateboard that has been getting a tow will go out and around you, flipping the bird on the way passed!

[baltobernie]

From memory the european 124 coupe was in the low 17 second range stock

Here are some published road test results from contemporary Euro and US car magazines:

engine size
HP
0-60
1/4 mile

1438, 96, 11.8, 18.3
1438, 96, 10.6, 17.6
1608, 104, 11.8, 18.7
1608, 104, 10.2, 17.6
1608, 104, 12.2, 18.6
1756, 86, 14.8, 20
1756, 86, 12.1, 18.5
1756 Abarth 9.5 0-60
2000, 96, 11.9, 18.3

To estimate the improvement in 1/4 mile times with 35 HP over stock, let's do the math:

predicted 1/4 mi. ET = cube root of pounds per HP x 6.269 (that's flywheel HP and test weight, including driver)

Big-bumper Spiders have a curb weight of 2365 lbs., according to these road tests. So with fuel and driver, let's say 2575 lbs. I agree with SoCal Mark that 139 HP from a 1608 is pretty ambitious (1.4 HP/c.i.)[87HP/litre], but let's say you got there. 2.64597705 x 6.269= 16.6 seconds, or about 2 seconds quicker. You new car would be 200+ feet ahead of the stock Spider; that's impressive.

139 HP does not necessarily mean that you'd have a great street machine. Someone here remarked long ago that what matters in a street car is "the area under the curve". In other words, print a HP vs. RPM chart and compute the square mm on the page below the squiggly line. That's how you compare engine-to-engine. A modern, EFI engine produces a lot of HP at fairly low RPMs. So your 139 HP Spider graph might have a shallow line from zero, while the Miata, let's say, has a steep line. Much more area under the curve, and a faster, more enjoyable street car. Even with 139 HP, don't go Miata-hunting. They now have 170 HP and 2400 lbs.