3.2 to 3.4 low on power - help me find the way
 

A shout out to the engine builders out there, as mentioned in the title, I’m trying to figure out why it seems I’m down on power.

A little background, car is a ‘71 euro 914-6 previously owned by member “0396” He’s since passed, RIP PL, the car was sitting for 4-5 years before his spouse decided to part with it. A few scattered records come with, from what I’ve found, engine specs are as follows:

3.2 case (930/25 215 hp 3.2) (confirmed)
stock internals
3.4 10.5 comp P&C
Twin plug (confirmed)
Web S cams
Webber 46 ida3c (rebuilt by me), w/ K&N type filters (confirmed)

Idle Jet: 50
Main Jet: 150
Emulsion Tubes: F7
Air Correction: 170
Choke: 42

Electromotive dual HPV-1 crank fire trigger (confirmed)
3.2 heads, intake ports 44mm, exhaust port 42mm (confirmed)
European Headers 1 5/8 (confirmed)
Monty dual in gt style 2 out muffler

I will update as I confirm items above.

Here’s the quick story, it running for 5 years, I bought it, fluid change, leak down (less than 1% across all cyl), valve adjust, Weber rebuild (idles at 55, main at 170), new plugs. Fired her up, ran like crap, super rich. After playing with carbs and adjusting ladles and jets to values above she ran pretty good. Felt like she struggled reaching higher rpm (ran out of breath) , took her to first track day at Willow Springs in June, ran fine but definitely no pull out of turns and low top end. Took her to Jeff at Aase in Fullerton, he found timing retard 12-15 deg, added it back, worker her up a bit on the street, top end still felt sluggish. Then Autoclub speedway in August, still no pull out of turns, better rev to redline, but still sluggish. Put her on dyno, got 164HP to the wheels which closely match dyno sheet provided in records from 2006 (169 HP).

So even in stock form seems a little anemic (25 hp or so). But with info provided above, and twin plug work, etc it’s more like I’m missing 100 hp at the wheels).

Please let me know your experiences and thoughts, or if you knew the PO or insight to the build. I searched and read I think all his posts in the engine building forum. Some hints that he may have been struggling with the same thing, but nothing conclusive.

Thanks in advance…

Photo for posterity:
http://forums.pelicanparts.com/uploa...1629530597.jpg

Here is the dyno sheet. Notice how I make all the torque before 3300 rpm….

http://forums.pelicanparts.com/uploa...1629530722.jpg

You are going a little lean above 5500. But I would start by checking cam-timing. I think you would be making max power closer to 7000.

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Talked to an engine builder about the cam timing (before I realized I was making torque so early). But he mainly said I might find a bit more hp in the cam timing, but really cam timing determines where the power curve occurs. He mentioned my major power loss is due to major air constriction in one or several places. As for late lean, I’ll post AFR logs from my LM2.

Was planning an engine drop and check on cam timing today - although that plan may be thwarted by a trip to the ER for my dad, day not starting off well…

Here we go, 5500 RPM still in the 13s…. But per dyno, I’m not making any power from 3200-4200, if you look at that range on my log, I’ve got a big rich dip, assuming that’s not helping power curve…

http://forums.pelicanparts.com/uploa...1629563760.jpg

That's rather ugly output given the engine setup. HP at flywheel should be about 260 or so at roughly 6800 RPM.
Here's where I'd go:
What's the compression / leakdown? Check it.
Check cam timing.
I believe venturies should be 38mm. IMHO, 42 is too big.
Ignition timing at idle and 6000 RPM?
Primaries, 1.5" for street or 1.625 for race are best.

Good luck!

A few thoughts/questions:
- I didn't notice which heads you have on the motor. 3.2? If so, I think those have 40mm intake ports. 42 mm venturis may be slightly large, but I wouldn't think it would much of an issue on a track car.
- It does look a little lean in the higher RPM ranges. I'd want to see closer to 12.5-12.75 AFR.
- Sounds like you got the timing sorted by Aase, but as noted above, it would be interesting to know what it's set to now.
- The Weber style K&Ns aren't necessarily the best, but they aren't going to cost you 100 hp either.
- Cam timing would be an interesting thing to check. It would be a little tight in a 914, but it's possible to check valve lift at overlap (per the factory cam timing procedure) with a valve cover off to see if it matches spec for the cam grind. If it were significantly off, it would certainly explain the power loss.
- In the thread on 914world, I saw the comment about cam timing being off 180 degrees. While that can happen, the affected bank wouldn't make power at all, and wouldn't sound right since it would be a 3 banger. It doesn't sound like that's your problem.

Silly question - are you sure your throttle plates are opening all the way? No flex or slop in the linkage?

I will offer two suggestions based on some dyno experience.
Check cam timing, Dyno below is from 3.0SC. The SC used the same cam as 3.2 Carrerra. There were different settings for different years. Dyno below is difference with cams at most retarded spec and most advanced. The run with more power and torque is fully advanced.

http://forums.pelicanparts.com/uploa...1629571691.jpg

Second thing to check would be to pull the muffler and try a run that way, Dyno below is different car that had headers with glasspack mufflers attached straight out the back. You could see straight thru the glass packs and owner thought there was no way they could be restrictive. Run with more Power is with glass packs removed.


http://forums.pelicanparts.com/uploa...1629571834.jpg

I would check cam timing and pull the muffler and see if it performs better.

john

If you are in the 13s you aren't losing much power, not 100 hoses anyway. But you can loose a lot in the cam timing, you have cams that want to produce power high up but won't let them if the timing is off. I would also check that the cams are what you think it is if you haven't built it.
I think the exhaust must be really restrictive to lose 100+hp, but its easy to check, annoy you neighbours with an open header test run :).

Good idea to try a quick run without the muffler. It would be a bit strange for an appropriately sized muffler to cause massive power loss, but who knows, there could be an internal failure or blockage. It's an easy test to do.

First post: ", leak down (less than 1% across all cyl)"

Unlikely with an exhaust blockage, its a thing that can happen in a catalytic converter, but I guess that isn't an issue with this car.

Being down that much on power is NOT restricted exhaust or cam timing off a bit.

Back to basics, are the throttles opening all the way? Is the fuel pressure dropping at WOT? Are the fuel filter(s) clean and fresh? Since it's an engine swap, are any fuel lines kinked?

Again, check fuel pressure AND fuel volume before changing a bunch of parts. Quick and easy tests. Throttle test: with the engine off, prop the gas pedal down with a stick wedged against the seat cushion, then observe the carb butterflies and physically verify that they're wide open.

A restrictive muffler wouldn't be evident on a leakdown test.

Thanks for the info and thoughts, keep them coming. I pulled the engine and confirmed a few more things yesterday.

Confirmed 1.625 primary’s on the headers and 42mm exhaust ports - heads are 3.2 heads, I forgot to check compression before draining oil, but leak down when out previously was less than 1% on all cylinders, I will check again though.

One thing I did notice was on the electromotive setup. From what I read the electromotive fires on both compression and exhaust so this shouldn’t matter, so each coil pack will fire 2 plugs at the same time (IE, 1&4, 6&3, 2&5) but spark plug wiring to the coil packs are slightly off. Firing order is 1,6,2,4,3,5, all the top plugs are on the upper set of coils, bottom on the bottom row, but the 6 and 3 are swapped on both sets, anyone think that might make a difference in firing?

http://forums.pelicanparts.com/uploa...1629652933.jpg

Pics of the leak down - this was done in feb… when I got the car, prior to running.

http://forums.pelicanparts.com/uploa...1629653667.jpg

Now that I have a few track days on it I’m curious what it reads now… hopefully the same…

Sorry, misquoted you instead of roblav.

Normally on twin plug wasted spark setups like Electromotive, you just want to make sure a given coil isn't firing two plugs on the power stroke at the same time. As long as it's not doing that, you should be fine.

I second dannobee's suggestion to go back to basics. I think fuel supply and pressure may have come up in the 914world thread. Definitely check those things if you haven't yet.

I'd still argue that an internally broken muffler, or cam timing being way off (not a little) can be included on the list of things to check. Muffler is easy to test too.

Unless one camshaft is 180 degrees off, then 1 and 4 would fire at the same time. It would fire on all cylinders and run pretty even, in theory, but what would really happen?

Engine is out now, I did some checking on the linkage at the motor, need to check bushings at the base of carb pivot, its a little sloppy. When it goes back in I’ll have to check that accelerator pedal opens throttle fully.

http://forums.pelicanparts.com/uploa...1629726662.jpg

I don’t suspect a fuel delivery issue, I’ve got two filters, both will be changed out again, also a pressure regulator and separate gauge after pump and filter, I suppose I could put a camera in there to verify no loss. See setup in the bottom of next photo.

http://forums.pelicanparts.com/uploa...1629727058.jpg

Also fram filter in frunk after pump, sorry for the bad pics, just want people to see what I’m working with…



http://forums.pelicanparts.com/uploa...1629727471.jpg

I wouldn't either since you have AFRs close to the right neighbourhood.

My stock euro 3.2 with ITBs and EFI have 220ish at the wheels. Your engine should be capable of 250 with larger capacity, higher compression and bigger cams.

This is my fear, everything adding up except a PO miscalculation of compression. I’d hate to find out I’ve got a twin plug 3.4 with 8.5 or less compression…

A turbo would quickly solve that issue.

Even low compression would not decrease power output this much.

An early S profile should give you about 78-80 crank Hp/L. Meaning - you should be seeing at least 225Hp to the wheels.

What pistons are in there? 10.5 doesn't mean much. Do they have valve pockets? ARe they CIS style pistons with a wedge dome? If there is a dome that prevents proper cam timing due to valve interference issues?

That engine should make over 200 ft pounds of torque. Peak torque should be at around 5500 rpm and yet you peak at 175 at 3k rpm.

Is there a chance of wheelspin on the dyno? The curves do not specifically show what I would call wheel spin but there are some strange steps in the outputs.

I would verify cam timing and also profile.

how much clearance do you have on the rain hats to the top of the stacks? Are they metal or plastic? Are they being sucked down from being too close? Are you limiting flow from being too close?

Not sure, the 10.5 came from a reference the PO made in one of his old posts here on the bird. I have a feeling he was sniffing around for similar answers, but maybe a bit proud? I pulled engine for the purpose of measuring cams and checking the mech timing. Thanks for the idea on timing due to interference, didn’t think about that, will report back.

Agreed! 189 tq at 3100-3200, tells me mech timing is off… why, I’m eager to find out!

There may be some wheel hop, car squats pretty good on pulls, I’ll post a link to a vid showing all three pulls.

Will do, clearance is about an inch, hats are metal. Along with muffler tests I could run them open for a pull as well….

Dyno link:

https://youtu.be/yXccX_duoEI

Consider doing quick runs with the filters + hats removed (briefly, don't want to suck debris into the engine), and with exhaust removed. Not sure either of these if your problem, but they're really easy to do and rule out.

I believe the idea is that you don't want two cylinders on the same firing cycle, firing at the same time (edit - for example top and bottom plugs on the same cylinder). In a wasted spark arrangement (and when set up correctly), #1 and #4 will fire at the same time, but only one of them is on the power stroke. Hence one of them is "wasted". I'd guess it's to reduce load on the coil of having to produce enough spark to fire two cylinders/sparkplugs on their respective power cycle at the same time.

Yes, what I meant was IF ONE cam is 180 degrees out in wasted spark cylinder 1 and 4 would be on power stroke at the same time resulting in... something strange, that would run.
Some moto gp bikes used this configuration and called it "big bang" to get traction advantage. Bigger bang spaced out more.
In an set up where cylinder 1 and 4 uses the same coil, it probably wouldn't fire reliably because there would not be enough energy in one coil to fire to plugs on power stroke.

Yes, it sounds really sluggish and strangled.

How is the throttle response?

It sounds off, like its not timed correctly or not hitting on all six.
Another thing to mention: It's running twin plug with two Electromotive HPV-1's, which run in waste spark configuration.
Usually one DFU runs the upper plugs, the second DFU runs the lower plugs. When checking timing with these units, you need to check timing on both the upper and lower plugs. The early HPV DFU's are not the most reliable. Mike Bruns has stated that he has seen them drift considerably.

Throttle response is ok, best describing word is LAZY, once out of the torque butt dyno is telling you to shift, look down and you’re only at 4500-5000 rpm, it’s painful to wait to shift after that.. At speed it immediately makes you think it needs a lightened flywheel…

I'm no expert , but I've built several Porsche race engines with Webers over the years. I think you should look at cam timing first. Next I would look at your jetting, 50 idle is too small, 150 mains are too small. On my 3.4 liter with GE80 cams I ran 65 idle, 160 mains, and 200 air correction at Willow Springs. Another important thing to look at is the enrichment ( accelerator pumps) you need to make sure its pumping, I'm not sure what the correct amount is per stroke, but make sure they're producing a steady stream of fuel when actuating the pump. Could be clogged , or the pump is not working. That's probably why you have no power out of the corners. My 3.4 ignition timing was set at 12 degrees BTDC at idle , and a total of 36 degrees at 7000 rpm. And I agree with the post above, the chokes ( or venturis) are a little large , but for a full race application it might be ok. I ran 36mm on my 3.4 liter . I was also running Electromotive twin plug, crank fired. One more thing to look at might be a ground problem on the HPV-1...... I had that happen at the track once, also had a coil pack fail as well. I hope some of this helps !

One last thing- I currently have a '77 backdate with a 2.7 liter, 10.3 CR, Weber 40IDA3c's, tall manifolds, and Elgin E cams. Mains are 135, idle 60, air correction 180, emulsion tubes F3, and the engine makes 245 at the crank. idle ignition is 12 btdc, 32 degrees total. just an FYI. Your 3.4 should be up around 260-270.
one more thing--- check the compression . you should see around 155 psi if you indeed have 10.5 :1 compression.

good luck!

Howard

Hate to say it, but in my limited experience, I went throught a similar situation. In my case, it turned out the pistons were low compression. Couple the low compression with a Mod S cam, and it ran like a dog. I pulled it down, rebuilt it with correct compression pistons, and it came alive.
While the motor is out I think you need to CC it. Until that is determined, so that you know definitively what you have (as opposed to what PO told you), everything else might not be time well spent.

Interesting because I'm going through something similar with jetting on a new engine I just built:
Carrera 3.0
9.5:1
Webcam Mod S cams
PMO sent 46's with 38 vents, 150 mains, and 50 idles.
Transition is bloody awful... weak.
Step 1 is try 60 idles. If not enough, then I'll go up on mains.

Had a couple of hours at the shop:
Took off carb assembly and measured intake ports at heads: 44mm (looks to have had some work done to them)
Checked valve adjustment : OK
Performed another leak down test: all cylinders less than 2%
Checked left hand cam timing: 5.18mm - points towards S cam
Still need to measure cam lift - gotta figure out reliable way to hold dial indicator.

Bolt a piece of steel bar stock to the valve cover surface using the stud. Then put a magnetic base dial indicator on the piece of steel.

What's the exhaust port size?

42mm exhaust…