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Mon Jul 02, 2012 7:01 am

Mark: thanks for the tips I just got a SOLO cup and put it on. Regarding the no venturi carb issue, check out the video on the previous post. it explains how it works without a venturi.
Joel and Everett: I found on in the classifieds and I'm ordering it
lostinbaja:Yes the SP head, the small carb and stock rockers are the limiting factor in the NA angine, ergo the blower. Now the engine sucks in 1000cc per rev instead of the 800cc asuming 100% efficiency.
Once I get the accelerator cable hooked up and I drive it I'll let you know if my ass dyno feels any difference.
I can already tell you by simply reving it that it has more power. It revs a lot faster.
Thank you guys for your support, tips and ideas.

Mon Jul 02, 2012 1:19 pm

I have never messed with a vw carb other than to take off 1 and throw it away,never seen a kad up close &personal, but after seeing yours I see where it will work,I didnt know it was made like that,I learned somethen. but dont forget to up the main air bleed along with the main jet.if you just up the main jet the fuell dont atomize&pull so good.if you ever look at a gm quadra jet carb & look into the rear barrels you would wonder how the eff does this work.when reworked & tuned right thet will fly.witch go's for just about any thing .have fun.

Tue Jul 03, 2012 5:23 am

Yesterday afternoon I drove it and it was pretty cool. I am still lean but I didn't get any detonation. That's probably because of the timing which is a bit conservative right now. Once I jet it correctly I'll advance the timing a bit more. Nevertheless, I did feel the difference when I punched it. I definitely has more torque.

Thu Jul 05, 2012 2:12 am

Joel wrote:

Those little Aisin AMR blowers self destruct on VW engines long before they create enough boost to do that.

totally wrong! i still have a amr300 on a 1200 36hp with 17 psi of boost and 80 hp out of a 30hp engine.... in daily driving since years. wrong tuning destroys parts. ist just a pump mine is good to 100 hp. amr to 150hp. the rest is on you how to make it. a amr500 on low boost can easily make 100+hp on a aircooled with no big tricks in tuning.

this statement ist totally bullshit joel and you should know it.

@mark tucker: small engines like a 1600cc and less don't like that big cams it's not a v8. the lost in breathing down below just makes heat. you compress the air /makes heat) but blow it through the exhaust. and too much cam makes it to a pig you know the saw idle of big cam, huge ratio supercharged engines?

@ el mao: at first very cool engine and car+ well done. i love the singleports but they will run hotten than DP's but thats not a problem. under boost they should be same a DP's powerwise. megajoilt is also a good choice to make it run perfekt even with a carb on it. gratulation. and the room without a dizzy ...looks very good.

your statement: " Now the engine sucks in 1000cc per rev instead of the 800cc asuming 100% efficiency. " is not correct.
for sure it will be blown ;)

but both has VE: the blower will be at about 85% with carb (in a hole system with engine, belt drive...)
the sp engine at its own at about 70-72% stock that is easily to calculate backwards from the stock HP at stock rpm

1585/2 = 792,5cc at 100%
your engine makes about 50 hp at 4000 rpm
1 hp needs 1,5 cfm
1cfm= 28,32 liter/min
1 liter =1000cc

50hp= 75 cfm= 2128 liter/min
2128 liter /min @ 4000 rpm = 0,531 liter per revolution = 531cc per revolution
thats what a 50 hp engine sucks per revolution at 4000rpm per revolution (the hole system with exhaust, manifold, venturi, airfilter, cam... belt drive lost, generator+cooling lost all is in this calculation)
and the blower will give you about 850cc when the ratio is a true 2:1

one step more is just a bet. your engine will peak around 4500rpm i bet. and with a big vent in this tiny carb i would say letzs try 85% and 80% in fact of the carb and co.
850cc x 4500 rpm should be about 90 hp.
80cc x 4500 rpm should be about 85 hp.

85-90 hp if the engine is tuned right. but i would give 10% +/- on it in fact of more stuff that is changed to stock engine. exhaust can make alot in a blown engine+++

good luck with the tuning.
in your case i could recomend you a cv 40(harley) or SU hs6 (mini and co) carburetor. they are sidedraft and will clear the top. just a 90° bow from the supercharger they both are bigger and very easy to tune, i made good efford with them on supercharger und turbo.

wishes from berlin germany
chris

Thu Jul 05, 2012 2:42 am

Hello.
What Grueni said.

3 weeks ago I dynoed a 1600 type 1 with an Eaton M45 charger. Blowthrough.
Engine is - 1600 cc. dual port.
Better valve job, intake guides shortened 5 mm and ground konical. cylinders machined to have 1,1 mm deck height. 7,8 CR. 28 mm venturi in carb. stock muffler, but with "clear" chambers in each side instead of all the reduction stuff. 25% more square to the center chamber and Homemade endpipes 250 mm dampening and 32 mm I.D.

It pulled 89 hp @ 4700 rpm and 171 Nm @ 3300 rpm. and has 0,8 bar of boost at 4700 rpm. I think I can find another 5 hp in it by finetuning the ignition timing even more.

The only problem we have with it, is a rich condition in the cruising rpm. But I think it is due to this carburettor is having a 140 idle air correction jet. (Which would be good for a N.A engine) I will try and swop carb to one with a 120 I.A.C jet, and see if that will reduce my fuel delivery at cruise.
Apart from that it runs super smooth, like a well trimmed stock engine, only 75% stronger.
I did not do the charger build up, only the engine and dynoing. The guy has modified a stock Ghia intake filter and hooked it to the charger. It runs almost 100% noiseless. The only thime you can hear tit is above approx. 4200 rpm and WOT. Then you can hear a slight snarl from it.

T

Thu Jul 05, 2012 3:11 am

hi torben.
what is the supercharger ratio?
and 28mm in the carb is not much i have 29mm in my 1192cc 36 hp engine.
this will be a restriction. what i found out in jetting:
very small air correction and kinda big main. but this is in a pci34.
but you can test it. the 140 air correction should be not the reason at first...depends on your idle yet.
can you post the hole jetting?

in my pci34 i have perfekt conditions. and also cruise with very lean but the engine likes it (very good ignition and smalle bore) and has no temp. problems. i have 0,7 mm air correction !

Thu Jul 05, 2012 12:21 pm

Chris, I dont remember the gear ratio on the charger, - 1,6 I think. (Its close to what the newer Mini´s run)
I will make 1 thing clear. This excersise with "our" 1600 supercharged was not to gain max power, more like achieving max driveablilty. That is also why I stayed at a 28 mm venturi, because with a 30 mm it had a sligth hesitation in the lower rpms that I couldnt get rid of. As soon as I swopped to the 28 mm venturi it dissappeared, and the engine will now handle a 4rth gear pull from just over idle.
We - have- discussed trying to increase the belt drive ratio to see if we could get 0,9 bar at 4700 and maybe hit 100 hp. But I think the charger will suck up too much of the gained power, so that in real life we will gain maybe 5 hp.

Jets in this one are:
Idle 0,65
IAC 140
Medium acc jet std (0,50 I think)
Acc pump jet enlarged 0,05 mm
Main jet, 140
Main air Z60

As said I will try a carb with a 120 IAC to see if I cant clean up that upper idle area.
T

Thu Jul 05, 2012 4:08 pm

I wasent thinking about a big roller cam,but a biger one than stock, remember building perssure in the intake because it cant get into the cylinders just builds more heat in the intake to shuve in the cylinder next time around.a biger cam can lower the boost&raise the hp.(depending on many factors)

Thu Jul 05, 2012 6:49 pm

Wow great posts. Lots of good info there.
So I drove it yesterday a little harder and it is awesome. I'm still a little lean which I will correct by soldering the air jet and redrill it to a smaller diameter. Eventually I was thinking about a Mikuni HSR 48mm. For some reason I really think that the carb is what is keeping me down.
BTW I have a counterweighted balanced crank with some decent rods and HD springs so I think I can rev up to a bit more than 5k rpm
I also think that I'm somewhere there between 80-90 hp
The biggest difference I notice is that before I didn't have much power above 3500 Rpms but now on fourth gear I can floor it and the speed goes up fast. I was doing 80mph in no time. Whoooohoooo!!!!

Grueni: danke, I spent a week in Berlin with a Cuban friend. Great times, I really liked it. Thanks for your input.

Thu Jul 05, 2012 11:24 pm

grueni wrote: Joel wrote:

Those little Aisin AMR blowers self destruct on VW engines long before they create enough boost to do that.

totally wrong! i still have a amr300 on a 1200 36hp with 17 psi of boost and 80 hp out of a 30hp engine.... in daily driving since years. wrong tuning destroys parts. ist just a pump mine is good to 100 hp. amr to 150hp. the rest is on you how to make it. a amr500 on low boost can easily make 100+hp on a aircooled with no big tricks in tuning.

this statement ist totally bullshit joel and you should know it.

Ok, wasn't quite the right wording on my part, what I should have said was there is a risk of that happening.

The AMR300s were quite common here in aus so there has been a lot of conversions done with them, I just know of 2 VW installs that have gone bang and a few more non VW conversions too.
There was 5 or more on Boostcruising/Ozgemini a few years back and they were all blaming running the fuel mix through them but I call BS, the fuel helps cool the blower.

Anyway a lot of it would also depend on the blower condition before the conversion, A free SC14 blower I scored you would swear had a million miles on it by how worn it was.
It probably wouldn't have lasted real long.

Fri Jul 06, 2012 7:21 am

el Mao wrote: Wow great posts. Lots of good info there.
So I drove it yesterday a little harder and it is awesome. I'm still a little lean which I will correct by soldering the air jet and redrill it to a smaller diameter. Eventually I was thinking about a Mikuni HSR 48mm. For some reason I really think that the carb is what is keeping me down.
BTW I have a counterweighted balanced crank with some decent rods and HD springs so I think I can rev up to a bit more than 5k rpm
I also think that I'm somewhere there between 80-90 hp
The biggest difference I notice is that before I didn't have much power above 3500 Rpms but now on fourth gear I can floor it and the speed goes up fast. I was doing 80mph in no time. Whoooohoooo!!!!

Grueni: danke, I spent a week in Berlin with a Cuban friend. Great times, I really liked it. Thanks for your input.

i had that mikuni on a amr500 on a high reving 1200cc 36hp (7800 rpm ans 0,9 bar boost) it is way too big. i would use one of that carbs i told you specially becaus it will be a driver. the piston style carbs help not to cut off the airstream.

your thinking about reving i agree but your cam will tell you the end ant thats good in your setup. but be carefull with that lean mixture.

when you come again to berlin send me a message and we can meet up. berlin is very small in aircooled vw so all of you are welcome her.

@ joel : your are right the risk is everywhere, also in aircooled only. its a system and just one weak part can destry alot. tuning is as much important than a functional mechanical system. . its like some people say a unballanced and specially the stock crank can not rev high and will break...but i know 2 guys that pushing 400 hp out of a 1641cc turbo with that both close to 7000rpm with such a crank in a just linebored case with good headstuds....specially that shows how important tuning is. tune well and your engine is your frind. a worn supercharger will definitly be a heatpump without power i also had one installed that found his way into the trash very fast, el cheapo is not allways the way to go ;)

wishes

@ torben: keep on posting in blow through you are right, you don't even need that big vent and the stock carb can produce alot of hp under boost.
1.6:1 ratio is 20% more than the 2:1 ratio here and there should be way more in it. something is choking you. ignition, exhaust but i bet the ratio is less than boost and hp output fit together. hope your finde some more hp. good luck. send me a PM and i can give you a very good tip specially for that setup.

Sat Aug 11, 2012 5:23 pm

I got my SC12 in on Thursday, got the bracket from Vintage speed coming next week, got the mockup motor out and I'm trying to decide which type of trigger ignition to use, but you have inspired me, so I'm going for it, I'll post pics after I get started. Wish Me Luck.

Sat Aug 11, 2012 5:45 pm

I wish you much luck,if you do it right it cam be fun and reliable.

Sat Aug 11, 2012 7:21 pm

el Mao wrote: The engine is a dual relief case
scat 69mm counterweighted crank
stock cam
stock pistons and cylinders 7.8 to 1 CR
stock rods
heads are singleport with single high rev springs and lapped valves
stock rockers
the fun stuff:
I got an AMR500 supercharger online for about $300 from Japan
the bracket is an AC kit from vintage speed Taiwan for about $300 also.
I later plan on installing a compressor and full AC kit.
I did some fab work on the bracket, the intake manifold, the carb...
and just in general to make stuff fit.
The carb is a 34pict that after seeing some guy on youtube run it without the venturi, got me thinking. I also removed the choke and anything else that prevents flow. I don't know if it will work but I'll let you all know.
oh and the ignition is a megajolt unit with a ford edis coil and controller. It worked great before the SC so it should work fin now.
I should get about 5psi of boost which is what all I want and think the engine can handle any more and I'll probably will runinto reliability issues.
I hope you guys like it.

Very cool man.

Fri Aug 31, 2012 10:55 am

Stickerdick wrote: I got my SC12 in on Thursday, got the bracket from Vintage speed coming next week, got the mockup motor out and I'm trying to decide which type of trigger ignition to use, but you have inspired me, so I'm going for it, I'll post pics after I get started. Wish Me Luck.

It's been a while since I checked this thread but I like what I see. If you want some close-up pics of the bracket tabs let me know.
I highly recommend the megajolt system. It is not hard at all to install and once you have it going you can fine tune it to your needs. Plus you can later megasquirt it if you wish.

So far the hardest thing has been the Carb. I finally ended up going to a stock 34 pict 3 german carb with the venturi. That carb I initially had, without the venturi, was a pain. Now I have better throttle responce and it stays around stoich throughout the whole RPM range.

Stickerdick: I recommend that if you are doing the SC12 you go with a larger carb. What are you engine specs?

Sat Sep 01, 2012 6:53 am

el Mao wrote: So far the hardest thing has been the Carb. I finally ended up going to a stock 34 pict 3 german carb with the venturi. That carb I initially had, without the venturi, was a pain. Now I have better throttle responce and it stays around stoich throughout the whole RPM range.

I can't remember the exact simulation numbers (they are hiding in my desk at home), but the air velocity drop with no venturi is not really worth the flow benefit in my opinion. The fuel will never mix correctly, and as you've discovered, there's just not enough pull to justify it. A few guys out of France showed some examples with a small 13-14mm boost venturi at the middle of the throat, that actually works well in theory and practice. It might still hurt throttle response if the engine doesn't pull enough vacuum. The solution to that would be running a bored out stock venturi, I think Art Tharen was working with them in 28 or 30mm sizes for desert racing.

Very cool engine build!

Sat Sep 01, 2012 11:07 am

Hello.
I disagree on the throtlle response with a larger than stock venturi in the 34 PICT carb in general. But in said configuration, the stock sgl port engine might not support the vacum to exploit it. I´m not sure. With dual port heads and a tad more cam, - even still 1600 there is a benefit... My 80 hp 1600 std plus runs with a 30 mm venturi and pulls clean from 1300 rpm in third and about 1500 rpm in 4rth. But the set up is cam sensetive, I´ll give you that much. It took me a while to figure out how.

Going back to the 1600 super charged I was writing about earlier. - The MSD boost retarder kept making issues with varius cut off´s and other weired stuff until it finally left my customer stranded in the middle of a 1 lane road work on the Motorway, with the entire family in the car. Needless to say that did´nt score much points from the misses.

We had a chat about it, and decided to try and run without it. So he softened the boost up a bit below 3000, adjusted the 009 down to 30 D. BTDC @ 2800 and went from 95 octane to V power. It does´nt ping, not even on warm days, to my great surprise. What also happened was that the engine actually became much more "sporty" to drive.
The dyno showed a slight loss of torque below 2700 rpm and max torque was moved up to 3400 rpm. (still 170 Nm) Max hp went up from 89 @ 4700 to 103 @ 5050 rpm. So the entire powerband has basically been stretched 500 rpm. Not bad IMHO.
I have just recieved a 170 mm crank pulley for flat belt. We will now try and increase the charger speed by 10% along with getting the Saab Dizzy converted to the VW and see where that gets us.

T

Wed Nov 21, 2012 7:46 am

So today I was going to work and two 1990ish honda acords were playing around racing each other in trafic and I got in on the action at a stop light. It was awesome. I was able to take them off the light for a little bit and then they caught up and just stayed there. Kick ass. So far I think this supercharger idea has been worth it.

Wed Nov 21, 2012 9:05 am

did you ever get it richened up or are you still lean with conservative timing?

Wed Nov 21, 2012 9:52 am

On my customers beforementhioned 1600 supercharged he had some "driveability" issues, with the charger being a little violent when coming on the boost especially at part throttle. It would sort of whack the bypass valve shut, start building boost and then "discover", hey, the thottle only moved 1/4" so we need no boost after all and then open quite rapidly again, resulting a somewhat kanguru style power supply. And the bypass valve would go tsh tsh tsh and then stabilize. SOOO, we had a chat again. He then decided to control the bypass valve manually and shut it completely at WOT. THAT HELPED ! Now it makes full boost 400 rpms eralier and is totally like a detailed stock engine, only almost twice the torque.
The hp is now about 110 hp @ 5100 and 180 Nm torque max at 3300, but very flat. With a 4,37 transmission (which is being swopped in favour of a 4,125 almost as we speak) it outruns most newer stock cars in accelleration from 50 to 100 mph. Minus Porsches and the likes :D

At this time we also discovered that there was a rather large pressure drop through the carb. 0,8 bar above it and 0,5 - 0,55 below the carb. So next thing is to get around to try a 28 mm venturi and see where that takes it. At some point the dynamic compression WILL get us into detonation area. (I thouight we would have been there already, but I must have done sumptin´right in the chambers, because it is only when you really provoke it after say a 15 minute ride at 100-105 mph that it can be heard in the lower midrange. It is at 10 -29 right now.)

We also discussed trying to fit a water to air intercooler. And I actually bought one I thought would fit, but it is too large :? So if that is going to be explored I think we will have to fabricate one for the car on the car.

T