How Much Power Can a 1600 Dual Port Make? We’re Finding Out!

[SGKent]

Naturally aspirated 1600 Fiat 124 engine, 140 HP. We could get 130 with a Weber progressive or 140 HP with dual carbs. I would think that the VW engine should be able to hit at least 125HP. The Fiat did not have the disadvantage of pushrods and it was cross flow.
_________________
"Most people don't know what they're doing, and a lot of them are really good at it." - George Carlin

[Alstrup]

125 hp from a NA 1600, and peak at no more than 6000 is a walk in the park. From around 140 it begins to get, if not complicated, then you need to know what youre doing in order to get a nice usable engine out of it.
_________________
https://www.thesamba.com/vw/forum/viewtopic.php?t=435993

[oprn]

[Root_Werks]

[Alstrup]

Draw throughs are a relatively easy way of getting quite a bit of a power increase. but in many areas it is not legal, at all. Next, while draw throughs are easy power they suck on cold start, idle and fuel economy. you pay a hefty price for the cheap power. But if the vehicle is a saturday night special, that part matters less for most.
Blow throughs are somewhat more complicated, but much more versatile and DD friendly once dialed in.
A 125 hp 1600 is relatively cheap and easy to build. Just stop "living" in 1995. That said, the difference between that and a 140 hp 140 is relatively small, so most would want the 1914.
_________________
https://www.thesamba.com/vw/forum/viewtopic.php?t=435993

[oprn]

I daily drove (our only family car with 2 children) a draw through for 4 years summer and down to -40 in the winter so it is entirely possible and practical. In fact it ran better the colder it got! This was 30 years ago and should be even easier with today's technology.

The only downside to draw through in my experience is the difficulty in incorporating an intercooler. All else is simpler. If I were to do a turbo today it would still be draw through or... go deluxe and blow through a single throttle body with EFI. All your usual blow through the carb problems would be gone!
_________________
Our cars get old, we get old but driving an old VW never gets old!

[BFB]

I gotta agree with Oprn on this one, although majority of my engines live in buggys and aren’t DD’s years round, the draw throughs ive built are not much more cold natured than any N/A’s ive owned or built if at all.
My draw through 2276 with the split shaft DCOE , being the draw through i have the most time spent with, runs & drives like a production passenger vehicle did in the 80’s , not going to say its as easy as a modern EFI car though and it definitely is cold natured, but once its been run and warmed it it’ll fire right up.
Last I mathed the mileage it was about 25mpg, not bad in my book considering how i drive it.
Ive built about equal amounts of draw through and blow through set ups and theres really only 2 determining factors when choosing which one to build for someone, 1. How much they want to spend and 2. Whether they will be driving in colder temperatures or not.
Aside from that they can both be tuned to drive about the same
_________________
"how am i supposed to torque the rear wheel nut to 250 ft lbs??? " - clonebug
An interesting thing happens in forums where everyone starts parroting the same thing and "common knowledge" takes over.
Most experts aren't.

[SGKent]

the numbers I gave were with a naturally aspirated (carb) engine, and not one with a turbo and boost. With the option of boost, it is simply a matter of how strong can you make things before the boost blows things apart or the engine glows red from lack of cooling and melts. The amount, of fuel and oxygen that combine, creates the heat that expands the air mass and moves the piston. It is that simple. Keeping it together is the challenge. You literally have to keep breaking things, and coming up with new engineering solutions to the causes of those things breaking, to know what the answer is to the question "How Much Power Can a 1600 Dual Port Make? We’re Finding Out!".
_________________
"Most people don't know what they're doing, and a lot of them are really good at it." - George Carlin

[oprn]

It's been done with boost many times over. Clonebug is the master of this quest on this forum. Go look at his build thread for the answers. These fellows are on the same path now, headed in the same direction and if they go far enough will come up with pretty much the same results.

Mario at The Dub Shop did a very similar one not too long ago but are now headed down the special trick parts road.

I was following this one due to the fact that they were initially testing bolt on bits for a 1600 N/A engine (which has also been done before but not in recent times as far as I know) but they got bored of that long before I was hoping and went down this well travelled path instead.

It's still holding my interest mostly due to the grassroots down to earth fun they are sharing but the quest they are now on has certainly been done before.
_________________
Our cars get old, we get old but driving an old VW never gets old!

[clonebug]

My best dyno run was 226 crank hp and around 255 lb. ft of torque but the engine didn't like it and it broke the ring lands on a couple pistons and also moved a small end rod bushing. All of that was below 5000 rpm. We were going to refresh the engine anyways so it was a test project....

Pushing an engine that hard will show it's weak spots especially on a dyno with multiple pulls.
Ignition advance and intake temps become a real issue especially on back to back dyno pulls as they found out.

Once you go over 15 lbs boost you need to be very careful.

I've said it many times that 130* F. is the critical point and the same posters call bullshit on it.
I'll bet they cracked their ring lands if it started puffing steam and they did it at 18 lbs boost......guess what temp the intake air was at that boost level????
Doing the math if draw thru can remove 100* F. intake temp from venturi effect..... at 100* F. inlet temp the IAT's at 18 lbs. boost would be 242* F. minus the 100 degrees of venturi effect....which puts it at 142 degrees........and that is a guess.
In an enclosed room it could have been more or less but at 20 plus degrees timing it was a ticking time bomb. Add a couple back to back pulls where the piston temp was high due to the load and.....boom.

I rest my case.......

There are quite a few 1600 challenge engines in Sweden and the surrounding area that have far exceeded anything I can imagine at over 400 hp.
They do use a big cam and rev to 8000 rpm but use stock heads, cranks and rods and get amazing results. They also use E-85 and massive intake plenums with very efficient intercooler setups.
Looking at the dyno graphs they have almost nothing below 4500 rpm but it is a steep ramp after that. It takes aggressive driving skill and antilag boost control to stay in the power band for consistent 1/4 mile times....something my daily driver isn't set up for.
_________________

[NJ John]

I just never heard of draw through being illegal in some cases. It’s always been popular at the track to this day.
_________________
1973 standard, yellow, lowered, 3” narrowed front, 1600 blo-thru turbo w/single dell 15.4@86, so far
11.41 et buggy. Long gone
Let’s go O’s! Let’s go O’s!
https://www.youtube.com/@AirSpooledGarage

[BFB]

[MTT3107]

I found this whole series a bit silly...

IMHO, natural progression should have been :

Headers
Dual carbs
Ratio rockers

And so on..
Instead, they went with that goofy setup, blowing air from the heater vents into the carb.

Then, installing a oxygen sensor ?
I think that there are very few folks who would actually do that.

And instead of testing a good combo of headers, dual carbs, etc., they went straight to a turbo setup...

Again, how many folks do actually do that ?

[BFB]

why waste money on " good headers , dual carbs, etc.." on a stock 1600 that does virtually nothing compared to boosting it? one of the first things I did to the first buggy I had was boost it.
I think if you have that mentality that you have to buy this and that part then you've swallowed the corporate sales kool-aide.
I do wish they'd have done other stuff before jumping to the turbo but really, there wasnt much more left to do.

if my performance options on any stock engine was either headers, carb(s), intake, etc. OR boost the stock engine, id always choose to boost the stock engine.
but yeh your right, probably not many do that. gotta get all the chrome, billet, and A/N fittings first

also, still waiting to see how clone bug came up with their 18lbs of boost being 242* F. ????
_________________
"how am i supposed to torque the rear wheel nut to 250 ft lbs??? " - clonebug
An interesting thing happens in forums where everyone starts parroting the same thing and "common knowledge" takes over.
Most experts aren't.

[EVfun]

[BFB]

[EVfun]

[Dan_Lockwood]

I touched the feed line from the two-stage high pressure cylinder that feeds the tank by accident and got a really bad burn from it. Once the air hits the expanse of the tank, I believe it cools quite fast to an average temp of hotter than ambient.

[MTT3107]

[Alexander_Monday]

Just for comparison, here is the discharge temp curve of my 1.5L twin screw supercharger at 2 bar with 68F inlet temp.
Turbo should be quite a bit more efficient at the lower end, about the same in the middle and a little more efficient at the upper end.
So at 2.25 bar the math probably isn't too far off.
Degrees F on left, Drive RPM on bottom.
At the end of the day though, after water to air intercooler only 3F to 10F rise logged so an intercooler absorbs a lot of heat.

_________________
Danth’s or Parker’s Law:
“If you have to insist that you've won an internet argument, you've probably lost badly.”

Alexander_Monday->What were the rings gapped at?
bedlamite->Almost enough.