Supercharger for Subaru?

Tweety · Post by **Tweety** » Sun Jul 08, 2012 6:37 pm

Big delays caused by gasket silicone.

This is the stuff I used.

With several leaks a week ago I pulled the custom manifold off to find this stuff had wrinkled up leaving some parts without a seal.

Put it all back together with this stuff

Wont know till morning as am letting it set. This is the gasket goo I used 30 years ago but was ibn a small red and white bottle with a brush. much easier to use with a tube. Sets hard but aprts easy to seperate. Glad its still around.

By the way Subie experts. what is the hhole on the RHS of this adapter used for?

likely something to do with the orig hitachi carbie.

Post by **TOONGA** » Sun Jul 08, 2012 6:42 pm

Tweety wrote:
By the way Subie experts. what is the hhole on the RHS of this adapter used for?

likely something to do with the orig hitachi carbie.

that would be the cold start warmer for the bottom of the carby, some people say it is there to warm up the carby, others say it is there to stop ice from forming on the carby. I believe it is there to leak and let water into the inlet manifold

TOONGA

Silverbullet · Post by **Silverbullet** » Sun Jul 08, 2012 6:48 pm

I always thought it was there to warm the carby thus helping to warm and vaporize the fuel better giving better economy. Also think de-icing has something to do with it...and of course designed to leak into the engine

steptoe · Post by **steptoe** » Sun Jul 08, 2012 7:07 pm

air bleed from one side of the block to the other ?? You'd think the coolant running through the water port of the inlets would be keeping things warm enough. I drill em out from the top, tap 'em with M12 and fill 'em up with a stud, with my LPG inlets.

Threebond makes some good goops too for gaskets of all sorts

Tweety · Post by **Tweety** » Sun Jul 08, 2012 7:27 pm

Thanks fellas for the quick replies. and it answered my question.

See when I took off the custom manifold I saw a fair bit of fluid in the engine manifold but it didnt smell like a full petrol smell. I reckon I've had water escaping into the intake form this point. anyway have lashed the area both sides of the gasket with the goo. next time I'll tap it Steptoe....and stud the f...ker.

My patience is wearing thin. Next time definately will have that manifold from sC to inlet as a two peice unit. but you live and learn.

Tweety · Post by **Tweety** » Tue Jul 10, 2012 7:35 pm

I've allowed for the gasket goo to set.

At least I know there are no leaks there now on that custom manifold.

Fiddled with jets a bit ended up with 145 mains and 6 degrees timing close to standard timing. But there is still just a little hesitation and as I got rid of most of it then it has to be a tuning issue. Wont know how ridable it will be until the rain stops.

Click on the next pic for a video

And yet again while fiddling with timing the engine backfired and that BOV worked so well.

steptoe · Post by **steptoe** » Wed Jul 11, 2012 8:28 am

Hope it is a plumb back BOV for th authorities

Tweety · Post by **Tweety** » Wed Jul 11, 2012 11:40 am

Sent you a pm Jonno.

Yes is a plumb back. you can see the 40mm PVC tubing back to the cold air intake.

Went for a ride today. Good and not so good.

Got 4psi on the gauge. am happy with that seeing as my ambition was 4-6. however I didnt have an opportunity to put the engine under much load as it would hesitate at anything more than the slightest throttle. I felt the vroom of the blower.

Steptoe might be onto something with the boost retard device. have to look into that.

Tweety · Post by **Tweety** » Tue Jul 17, 2012 9:13 pm

Today was more sweet than bitter but it could have easily turned horrible.

Took off at 6:30am bound for Croydon to my friends at VW performance Centre. Got to yea and broke down at the servo when Tweety's engine wouldn't restart.

Turned out much later that there was a lot of condensation in the electronic dizzy. Not the first time!

Eventually restarted and the engine broke a supercharger belt at Glenburn. Inspection revealed the belt had a tendency to move towards the engine. Later Daniel from VWPC found it was out iof alignment by about 3mm resulting in one of the 5 ribs on the belt to fray, break then the rest of the belt followed.

Luckily I had a spare and pushed on from Yea to Ringwood East where the second belt snapped. I heard it go. But pushed on regardless and found that indeed the engine can maintain power without the belt...no boost of course.

So Daniel took about 2 hours to make a spacer between the crank pulley and the SC ribbed pulley, plug weld it together etc. Then it was dyno time.

I had had 145's as a main jets in the 40 DHLA Dellorto,. In the end we had 225's so you can imagine how lean it was running. Air jets were matched. Accelerator "pump" jets had to go to greater sizes too. Initial runs were disappointing. Last years HP maximum was 60 hp at the wheels. These runs were 58. I asked Daniel to check the throttle. Yep...less that half effective throttle when squeezed tight- my fault. We spent some time remaking a better throttle set up with more throw and a better link.

82.2 hp at the wheels compared to 59.6 last year. a good jump of 32% in hp. I began to raise a smile.

Torque last year was 440lb this year 570. another substantial increase.

Here is the graph. The green is last years results after the weber carb was installed. Todays is in red. Power is the humped curve, torque the flatter lines.

That was at the wheels. last year the flywheel HP was 75. This year....well we got it way up toward 98 then we had an issue. The engine firstly wouldnt idle under 2500 rpm. Then it wouldnt start. The condensation was blown out with air. Then Daniel found a leak between the custom manifold and the base adapter plate. I recognised that spot. The gasket and hence the gasket goo area was less than 3mm wide between the intake neck and the mounting stud.

So we packed up our box of tricks and decided I'd remake the manifold. Daniel supplied me with some 75mm pipe and a leice of 75mm silicome tube.

Homewood bound and the difference was- well extraordinary particularly acceleration between 80-110 kph. Truly quick by previous standards. Tackling hills is a breeze where previously I'd drop speed to say 80kph or even drop down to second the trike maintains 100 kph effortlessly. When the trike does hit a slower steeper incline and drop down to second the front of the trike lifts. Not off the ground at that speed say 60kph but you do get that sensation of the machine sitting on its haunches- nice. Timing was eventually set at about 12 degrees which surprised us. And no pinging on the way home that I could detect. And the advance left alone.

Boost max indicated was 5psi. I think I'll be happy with that. I wont rule out at a later time changing the SC pulley to a slightly smaller one to get a bit more boost but I'll leave it alone for some time yet.

Now to rebuild that manifold and get the manifold between the Sc and the carbie shortened to make way for a wider air box

thunder039 · Post by **thunder039** » Tue Jul 17, 2012 10:10 pm

wow look at that torque!

Tweety · Post by **Tweety** » Tue Jul 17, 2012 10:29 pm

Yes, thunder 039.. 32% more power and average 30% more torque. Bit more than I expected.

I was surprised I only got 5psi boost from the pulley sizes I have. I though 7-8psi. but the ea81 manifold as we know isnt all that efficient and the volume efficiency isnt tops either. all in all it adds up to a little loss here and there.

The design of the short custom manifold was ok, just didnt leave enough room for nuts for the studs. And not enough meat for a good seal. and the lynx manifold is too long, want to halve its length. It will all get sorted next week or two.

The results are really pleasing.

YouTube · Post by **El_Freddo** » Tue Jul 17, 2012 10:41 pm

Always making progress - that's only a good thing mate!

Cheers

Bennie

steptoe · Post by **steptoe** » Wed Jul 18, 2012 8:38 am

that torque rating in lbs ain't foot pounds surely ? Not the usual torque rating used and reported ? for other engines ?

Gannon · Post by **Gannon** » Wed Jul 18, 2012 9:06 am

steptoe wrote:that torque rating in lbs ain't foot pounds surely ? Not the usual torque rating used and reported ? for other engines ?

That will be the torque that the dyno machine measured, not adjusted for the gearing, tyre size and diff ratio.

Sent from my new touchy phone thingy

Tweety · Post by **Tweety** » Wed Jul 18, 2012 1:08 pm

I'm no expert but "tractive effort" on the RHS of the graph might mean something.

But yeh, it isnt the standard torque output reading. its more a comparison. Actually my mind at the time was transfixed on the 82HP. lol

But below is a comprehensive explaination. Just for you Steptoe. I cant understand a word of it but you might!!

Compliments from a guy on Ford Forums.

Dyno's - Torque and Tractive effort explained!

--------------------------------------------------------------------------------

Howdy folks.
Well today we are talking about tractive effort. Often confused for torque often thrown around but its not that simple. Tractive effort and torque are 2 different things. Now lets get into it.

Tractive effort is determined by a few things - Motor torque, Overall Gear Reduction (including gearbox and differential ratio's) and the rolling raduis of the driven wheel/tyres under load.

Whats that mean?
Motor torque - The stuff they crap on about when you buy the car to tell you how much pulling power its got.
Overall Gear Reduction - Overall Gear Reduction is basically how the gearbox and differential gears tie together and how they make an impact on how fast the wheels are turning on the dyno for given rpm.
Rolling Radius - Exactly that. The radius of the wheel and tyre under load on the dyno.

We are going to use BigAl's ute as an example and find his true torque reading in kg/mm (mmmmmmm metric)

First we need the gear reduction. we'll call that R. R = RPM times rolling radius(call that r and its in mm) of the loaded driving tyre divided by 168 tmes the vehicle speed in mph (or 2651.51kph)
in other words R = (rpm * r) / (2651.51 * kph) ahhh math!!!!! math is good!!!!

Allens max torque was pretty much dead bang on 4500N @ 94kph. We are just using this as an example so we wont be 100000% exact with the figures (it will give us a rough idea none the less). Now lets pretend he is running a 235/45/16 tyre (i think thats what he races on...) the tyre is 308.95 in radius, and at 94kph its pretty much smack bang on 3000rpm. It also 3.7's in the bum.
Now we have that info - simple
R = (rpm * r) / (2651.51 * kph)
R = (3000x308.95) / (2651.51x94)
R = 926850 / 249241.94
R = 3.71868
There we go - Overall gear reduction solved and rounded to 5 decimal places.

Thats that, now lets figure out his torque in kg/mm using this information along with his tractive effort. This where it gets exciting!

Where: TE = Tractive effort, R = Overall Gear Reduction, r = Rolling Radius and T the motor torque!!! get the info from earlier put it on a bit of paper and go through it with me.

TE = (T * R * 1000) / r
4500 = (T * 3.71868 * 1000) / 308.95
multiply both sides of the equation by 308.95 our tyre radius and we have
1390275 = T * 3.71868 * 1000
divide both sides by 1000
1390.275 = T * 3.71868
divide both sides by 3.71868 our overall gear reduction
373.862 = T

So the engine torque is 373.862 kg/mm. (afaik kg/mm and nm are one and the same but i HIGHLY doubt that - got no idea really hehehe)

NOW half the reason of this post was to inform others on comparing torque graphs between themselves: person A cant go to person B and say i made so many newtons : oh yeah, im running the dyno in 3rd on a manual with a hilux diff and 5.3's in the bum.

Lets put a 3.45 diff in Allens ute and recalculate it all and see what the final torque figure will be given the same Newtons.
fast forward
4500n
101kph
308.95mm dia tyre
3000rpm
3.46095 Overall Gear Reduction
BINGO! overall gear reduction has changed therefore for the same newtons on the dyno it should be making more kg/mm at the wheels. Lets see if this holds true.

4500 = (T * 3.46095 * 1000) / 308.95
1390275 = T * 3.46095 * 1000
1390.275 = T * 3.46095
401.703kg/mm

There we have it! if 2 cars are making the same Tractive Effort (N) on the dyno it doesnt really mean they are making the same engine torque! Tractive effort can only ever be compared when the drivelines in each of the cars are exactly the same (manual run in 4th gear and auto in 3rd) same diff gears and yes even the same tyre size!!!!! thats when tyre pressure and tread depth all come into it!
You could call it a trick the dyno hides to the uneducated on the topic.
Now instead of me running around the forums saying no no you cant compare tractive effort between cars blah blah blah without no explanation here is the math behind it all. Hope you all understand

Happy motoring

Regards,
George

steptoe · Post by **steptoe** » Wed Jul 18, 2012 11:28 pm

I understood the blah, blah section

Tweety · Post by **Tweety** » Thu Jul 19, 2012 8:13 pm

Yes, a bit confusing eh.

But it does mean that Tractive is not lbs.

So the graph readout regarding torque is for comparison only.

Until someone can explain it in laymen terms.

Gannon · Post by **Gannon** » Thu Jul 19, 2012 8:49 pm

I did, but I'll try again.

Torque that is stated by the manufacturer is taken at the flywheel and measured in ft/lbs or Nm of torque, for this example we'll use ft/lbs.
Say for ease of calculating, the EA81 has 100ft/lbs of torque at the flywheel at 4000rpm, which is 76hp at 4000rpm. hp = torque x speed / 5252

Now all cars have a gearbox and a differential which changes speed and torque. When a gearbox halves the speed, it doubles the torque. This is why you have more acceleration in lower gears. It also operates in the opposite way, so double speed and you halve torque.

Assume we put our 4 speed manual gearbox in 3rd gear as this is close to a 1:1 ratio, then we just have the rear diff, which is 3.9:1
So for the tailshaft is spinning 3.9 times as fast as the tyres.

Do a few calculations and we have 4000 engine rpm divided by 3.9 = 1025rpm wheel speed turning the dyno wheels
100ft/lb x 3.9 = 390ft/lb of tractive effort turning the dyno wheels

I have left out calculations for you wheel sizes because they weren't really relevant here.

Notice that even though we have almost quartered the speed, and almost quadrupled the torque, power output remains the same because power is the multiplication of speed and torque.

Tweety · Post by **Tweety** » Thu Jul 19, 2012 9:03 pm

Thanks Gannon. Much appreciated.

Tweety · Post by **Tweety** » Mon Jul 23, 2012 12:06 am

Taken the custom manifold off and also the alloy adapter plate between that and the intake.

Taken Steptoes idea to tap a 12mm hole in that hole that has radiator fluid in it for the carbie and plugged it. Done.

Noticed the redline adapter plate I've taken off has only 1mm of "meat" between the intake hole and the stud front left hand side. No wonder it leaked. The new base plate I've made up has much more meat to seal fully. Made it from 10mm steel plate.

Made the rest of the manifold to fit then cut it in two peices where the silicone hose will slide over it to give me that few mm's adjustment if required. Made up another mount for the top of the SC12 as there is one less hard mount holding it firm. Took off the lynx Datsun carbie manifold so my engineer can halve its length and alloy weld it together. This will give me about 80mm or more for a deeper airbox that wont restrict the air intake for the carbie. Pics next week.

All of the above was due to the install being a fresh one with little real info on the project apart for Joels VW thread on aussieveedubbers. And I have a roof- not common- none actually in existance like this roof so when it tilts back the frame restricted the airbox size right down to 30mm thick. Hope others benefit from this thread if doing an ea81. With s/steel plumbing to come for the BOV link etc I'm hoping the overall package will be very attractive and interesting.

For those interested there is a Euroa show and shine first Sunday in October where Tweety will be on display with Sylvester (caravan)... By then it will well and truly be sorted...and left for many kms of reliable riding.