G’day fellow Veedubbers

I am new to this forum, but by no means new to the VW scene.

The reason for my post is to gain opinion on engine combo vs expected horsepower.

I recently had my brand new engine dyno’d which confirmed my suspicions that the engine was putting out less that expected.

I will list my engine specs below if I can gain feedback on:
- What horsepower I should expect
- What I can do to find any missing ponies and/or improve HP
- What loss through the trans I should be expecting

The engine is in my 69 beetle which I am building for street/weekend use, but want some really decent power while also having good driveability. I am happy where the power is currently between 2500 and 6000, but just expected more.

Engine is 2165cc
- 78mm CW 4340 Crank
- Lightened Flywheel
- Standard length I Beam Rods
- Engle W120 Cam
- 1:1 ratio rockers on solid shafts
- MOFOCO 050 Heads, 42mm Intake/37.5mm Exhaust, Port and Polish, supposedly 155 cfm @ 0.450 lift, Match ported manifolds **
- 9:1 CR
- 44 Weber IDF’s, 36mm Venturi’s, Air correction: 200, Main jet: 140, Idle: 0.60
- 1 5/8 Inch tuned A1 Sidewinder exhaust

The engine put out 106HP at the wheels @ 4700 and a pretty flat torque between 2500-4500 of approx 120NM at the wheels.

I run 205 60 15’s on the rear and the trans has a heavy duty diff, 3.88 r+p with Welded 3rd & 4th gears.
Usually HP loss is in the vicinity of 15% at the wheels, which means I am seeing 125HP at the flywheel.

Dyno read out attached FYI

** I matched the manifolds myself, as they came standard. These were in the kit from Redline, I have wondered about the restrictive nature of the manifold further inside about half way up to the carbs. From what I can measure it is more like 32mm diameter inside here – is this something I should look at also?

Any advice would be much appreciated.

I think it would also be useful if a thread was started which detailed engine combo and HP output.

Cheers in advance

Cam

A couple of quick ideas, the really basic stuff, with lots of fudge factors for the real world! The proper maths to do it is accurate, but takes pages of crap for formulaes.

Head flow at valve lift in CFM@28" (minus 10% fudge factor) = expected and likely HP.

Engine capacity x engine state of tune will give expected and likely torque, multiply/divide by expected HP peak rpm to get power.
Optimised race motors = 80lb/ft/L.
Really good motors = 72lb/ft/L.
Street good motors (eg 4V Honda, etc) = 65lb/ft/L
Older stock "dinosaur" motors (like stock ACVW & 186 Holden) = 60lb/ft/L.

Head flow at 0.435" lift is probably 150cfm, -10% = 135HP.
Street motor 2.165x60 = 130TQs, expected peak I'd guess at 5500. therefore expected HP = 130 x 5500/5250, which = 136HP @ 5500.

Check the manifolds first. That 32mm intake restriction effectively means you've made your carbs into 40IDFs with 32vents. I would aim for 44mm at the carb end, then match-port the manifold end with a gradual taper all the way down to the head. Then make sure the air filters flow enough air for the carbs (air filter flow equals Pi x diam x Ht x 6, eg a 6"round x 3" tall filter flows 340cfm........when perfectly new and clean).

Did you 'tune' it on the dyno, or just check the power level?

Without knowing the pressure drop at which the heads are flowed
with YOUR manifold and carb,
you are just guessing at this point.

Once you have got the tune correct,
Then you can work out where you need to make some gains.

Even if it flowed that 155 figure with the carb and manifold,
it would never make more than about 155FW if that number was at 25" pressure drop.
...well unless the planets align.
Minus your 15% gives you about 132 wheel.
I have seen between 10% and 15%.

Some engines do make as much or even a little more
than the same HP as CFM at 25",
but this is not often with VWs since there are many things difficult to optimise,
and most owners dont use the dyno as a tuning tool.

My guess is tht with manifold and carb it would be a lot less than the 155cfm at 25".

Also perhaps some one familiar with IDF's can chime in,
but that jetting will probably go lean up high.

What does the mixture curve look like?

Jetting wise... a 140 main and 200 air on a 36 vent am pretty sure will be going lean'ish from about 4500 up. Probably not break stuff lean, but definitely out of the power lean.

I also think your 60 idle jet is covering up the lean main down low... esp if your torque and power dip at 110 equates to 3000-3500 or so rpm... idles transitioned off before main has really started to kick in.

I'd be thinking 55 idle, and a 145 or possibly even 150 main with that 200 air, but yeah - having an AF curve would be a real big help.

I know from both my IDF days and now the EFI that tiny changes in AF can really hide or unlock power... like getting from 119 to eventually 132rwhp just by changing jets and vents with a prev incarnation 1915.

Plus restrictive filters (Uni) to flowing filters (K&N) can be 4-5rwhp alone.

Quote:

Originally posted by modnrod A couple of quick ideas, the really basic stuff, with lots of fudge factors for the real world! The proper maths to do it is accurate, but takes pages of crap for formulaes. Head flow at valve lift in CFM@28" (minus 10% fudge factor) = expected and likely HP. Engine capacity x engine state of tune will give expected and likely torque, multiply/divide by expected HP peak rpm to get power. Optimised race motors = 80lb/ft/L. Really good motors = 72lb/ft/L. Street good motors (eg 4V Honda, etc) = 65lb/ft/L Older stock "dinosaur" motors (like stock ACVW & 186 Holden) = 60lb/ft/L. Head flow at 0.435" lift is probably 150cfm, -10% = 135HP. Street motor 2.165x60 = 130TQs, expected peak I'd guess at 5500. therefore expected HP = 130 x 5500/5250, which = 136HP @ 5500. Check the manifolds first. That 32mm intake restriction effectively means you've made your carbs into 40IDFs with 32vents. I would aim for 44mm at the carb end, then match-port the manifold end with a gradual taper all the way down to the head. Then make sure the air filters flow enough air for the carbs (air filter flow equals Pi x diam x Ht x 6, eg a 6"round x 3" tall filter flows 340cfm........when perfectly new and clean).

Quote:

Originally posted by Sides Jetting wise... a 140 main and 200 air on a 36 vent am pretty sure will be going lean'ish from about 4500 up. Probably not break stuff lean, but definitely out of the power lean. I also think your 60 idle jet is covering up the lean main down low... esp if your torque and power dip at 110 equates to 3000-3500 or so rpm... idles transitioned off before main has really started to kick in. I'd be thinking 55 idle, and a 145 or possibly even 150 main with that 200 air, but yeah - having an AF curve would be a real big help. I know from both my IDF days and now the EFI that tiny changes in AF can really hide or unlock power... like getting from 119 to eventually 132rwhp just by changing jets and vents with a prev incarnation 1915. Plus restrictive filters (Uni) to flowing filters (K&N) can be 4-5rwhp alone.

Those Mofoco heads are OK for what they are, despite the "web experts" saying otherwise. The casting quality is very good. Don't confuse as-cast with mild CNC work 42 valve flows with the stuff you would expect from a decent race-blended ports. You could easily spend another $600-800 just to pick up an extra 15HP over 5000 where you hardly ever spin it up to.
If they flow 155cfm @ .450", they might also flow 165cfm@.500" as they are (and I would expect flow to keep rising at least to 0.550" lift, and you can access that extra flow with 1.25 rockers on what you have (they do work well on Engle120s).

4700 is a bit low I think for peak HP with those components, but where the maybe-missing 600-900RPM and 20HP is I'm not sure. That's where the fun starts I guess!

There certainly a lot to consider, I agree that the intakes are an area for improvement. I have built a few 2165s and around 100hp is common, but with smaller cams and less compression so certainly something is amiss with your package. What deck height have you set?
Personally, I keep away from 1.25 rockers, but leads to the question of what valve train do you have, rockers, springs and pushrods? Possibly your running out of lift due to problems there as 100rwhp from a 2165 with 40 IDFs and W100 with type 3 super short manifolds and 8.3:1 CR was a recent build of mine (with my stage 1 porting on 044 round ports 40 x 35.5).

http://www.cbperformance.com/ProductDetails.asp?ProductCode=3157 

^^ they need work too Mick

http://www.csp-shop.com/cgi-bin/cshop2/front/shop_main.cgi?func=det&wkid=...

The CSP manifolds would be pretty close; but as Matt says if you really want to optimize an engines combination of parts they all need work

Um, somewhat off topic guys but I was just wondering why I always see dyno graphs in Oz with Kilometer as the x axis? I was always used to RPM scaling in the UK and so confused how you know at what rpm the motor is producing what power?

Otherwise, interesting thread I never knew the max HP was that closely related to head max CFM. Nice baseline to go on when playing with heads and manifolds

Quote:

Originally posted by psimitar Um, somewhat off topic guys but I was just wondering why I always see dyno graphs in Oz with Kilometer as the x axis? I was always used to RPM scaling in the UK and so confused how you know at what rpm the motor is producing what power? Otherwise, interesting thread I never knew the max HP was that closely related to head max CFM. Nice baseline to go on when playing with heads and manifolds

Quote:

Originally posted by RAW069 Quote: Originally posted by psimitar Um, somewhat off topic guys but I was just wondering why I always see dyno graphs in Oz with Kilometer as the x axis? I was always used to RPM scaling in the UK and so confused how you know at what rpm the motor is producing what power? Otherwise, interesting thread I never knew the max HP was that closely related to head max CFM. Nice baseline to go on when playing with heads and manifolds Rpm's can be calculated from gear ratio, ring and pinion ratio and tyre diameter. There are also some easy calculators online.

Ok guys, latest thinking.

I obviously need more air into the engine.

There are a couple of things I could look at with the current setup being:

- More porting on existing manifolds
- Bigger venturis
- More porting on heads - I don't think this is worth the expense, and am probably better off purchasing CNC ported heads that are fit for purpose rather than $$ on existing - then I can sell my current heads to someone that wants this level of power.

So what I am thinking is, as I was looking at pulling the motor down anyway and performing a level of blue printing and doing all the check that will instill confidence in the motor, I might invest in / start collecting bits:

- New set of heads, looking at DRD L6 heads
- FK89 cam
- straight cut cam gears
- new pushrods (chromoly)
- 1.4 rockers/solid shafts
- match ported manifolds by DRD with the heads
- bigger venturis on my 44 IDF's - maybe 40mm??
- keep the CR at 9:1 (thoughts??)

What are the thoughts with this setup??

I still want it drivable, but am happy to sacrifice some drivability such as rough idle etc.

And I want my power say from about 2500 - 3000 up to below 7000 rpm.

Cheers

thats a damn big cam, you wont need that....is this a street engine, occasional blast at the drags??

cheers fabo

Did you see this...?

http://forums.aussieveedubbers.com/viewtopic.php?tid=25222&page=1 

I think your doing fairly well with that cam in there

Umm... W120 with 1.1's to an FK89 with 1.4's is a pretty damn big jump... you realize that's like an extra .150 in overall lift ???

Wouldn't come onto power till fair bit higher than your 2500-3000 I'd think too...

I'd be looking at both the manifolds and tune first, especially if engine is "brand new" as you said in original post.

In all seriousness, how does the car drive as is... is it spot on everywhere, good temps, economy etc... or is it becoming more about the number ?

I had my 2276 on the dyno and with a jet change and went from 75 atw to 105 atw on a slipping clutch, my tq was 178ft.lb with an oil leak fix who knows, but jetting is essential. At the moment I run a fk10 and is a great cam for the street if you are interested to know.
Hope you get some good headway.