Tracking the 914 - Happy New Year!, Turning this into a regular thing... Options

[Justinp71]

Air filters are K&Ns with a flat rain shield type top. Exhaust are equal length 6 headers at 1.625 and a monte 2 in 2 out muffler.

I'll chime in about the air filters with rain hats....I found that mine only had slightly more than 3/4 inch from the top of the velocity stack to the metal lid. That caused what I think was significant shrouding of the air flow. My solution was to go to the ITG type filters that have only foam above the edge of the stacks so no shrouding will occur...ymmv...

Hmmm that did cross my mind, but I see this setup consistently, so I dismissed it...could be why she seems out of breath on the top end...

I dont think rain hats are your issue, I run them and mine doesn’t run out of breath.

My carb setting notes-
• 38mm vents
• 160 mains (give 12.8-13.4 afr wot max, @68f air temp) , (170 mains give 12.0-12.6 afr WOT)
• 190 air
• F11
55 or 60 idle, 1.76mm IAC


Its a 3.2,dc40 cams, 9.5:1 comp, a very similar motor with slightly larger headers made ~255hp at the rear wheels which comes out to around 290hp crank.

I think there is something fundamentally wrong, spark plug wires crossed, timing way off, maybe the po installed stock 3.0 heads, cams going flat or valves need to be adjusted... or something wrong with the carbs and they are dumping too much fuel.

[stownsen914]

Been off the forum a couple days ...

I don't see anything fundamentally wrong with the setup. Sure, jetting could be off a bit, rain hats sit close to the stacks. I'm sure things could be optimized, but these things aren't costing you 100 hp. I agree with Justinp71 that something more fundamental is way off. I think taking the car to an experienced Porsche shop to do some tuning may get to it. It may be worth looking at some basics to see where things may be off. Ignition is an easy one to check - I can't recall if you mentioned what the timing is, but maybe check it with a timing light. Maybe check the spark strength with one those spark tester gizmos. Could the muffler be plugged up somehow? Monty is supposed to be a decent muffler.

[Krieger]

What do your spark plugs look like? I was using my AEM mixture meter for tuning my carbs. What I didn't realize was that my O2 sensor was toast. My spark plugs told a different story than the air fuel meter.

[Krieger]

Oh, I dynoed my 3.0 with and without the water shields. Back to back runs. 10hp at the top end only. One day I may switch to the ITG style or do my own thing.

[infraredcalvin]

Only got 1/2 day in the car today, I have an appt to take it to Aase Motors in mid June, so I wanted to look at some of the other issues plaguing the car.

Font bumper off and brakes bled.... bumper is too tight to body work, hood overlaps the edge, so I gotta put some spacers or find some dog bones to offset. Front left didn’t bleed, looks like I’m rebuilding a giant caliper... that appears to be the hanging noise I heard on track.

[Justinp71]

Wow! Those brakes are huge!

[infraredcalvin]

Started to take things apart, realized after removing pads that one piston was slightly stuck (turns out it was really low on fluid) I got it loose and started looking at the bleeders themselves. Both were crudded up. Poked a needle in there and cleaned them out with carb cleaner, then reinstalled and bled out the remaining old fluid, worked great!!! No more embarrassingly loud squeak every time I touched the brakes! This should put some confidence back into my braking on track. Drove her around a bit and got some gas. AFRs are not that far off... still feels pent up, I know she wants to go fast....

[Justinp71]

Started to take things apart, realized after removing pads that one piston was slightly stuck (turns out it was really low on fluid) I got it loose and started looking at the bleeders themselves. Both were crudded up. Poked a needle in there and cleaned them out with carb cleaner, then reinstalled and bled out the remaining old fluid, worked great!!! No more embarrassingly loud squeak every time I touched the brakes! This should put some confidence back into my braking on track. Drove her around a bit and got some gas. AFRs are not that far off... still feels pent up, I know she wants to go fast....

Cool. Did you check the firing order is good? What was your afr at WOT?

[infraredcalvin]

I’m dropping off at Aase tomorrow, hopefully some answers shortly…. If anything it’ll help me reach a baseline.

[Justinp71]

I’m dropping off at Aase tomorrow, hopefully some answers shortly…. If anything it’ll help me reach a baseline.

Cool!

Does your car stay cool on the track? I had to open up the front of the body alot more than you to keep my temps down, but I am also running the stock GT front oil cooler.

Also how is your rear suspension setup? do you like it? Mine seems a bit soft and feel like the trail arms move some. I'm probably going to do the Rebel racing rear bushings like I did in the front.

[sixnotfour]

one cam is 180 out of time,,,

[infraredcalvin]

I’m dropping off at Aase tomorrow, hopefully some answers shortly…. If anything it’ll help me reach a baseline.

Cool!

Does your car stay cool on the track? I had to open up the front of the body alot more than you to keep my temps down, but I am also running the stock GT front oil cooler.

Also how is your rear suspension setup? do you like it? Mine seems a bit soft and feel like the trail arms move some. I'm probably going to do the Rebel racing rear bushings like I did in the front.

Car keeps its cool so far, but without proper shrouding it appears it is really inefficient. If I make it to Fontana in aug, that’ll be the rapture test (last year it was 114 in the pits). So far my gauge is telling me the hottest it’s gotten Ian 100 deg C (212F). If I close up the hood though, I’d bet I don’t have enough exit area in the floor…

Suspension seems ok, tires are old Toyos, they seem a bit unpredictable, but prob cause they are aged out, right now these are the last of my worries, I’ll replace with new A052s when I’m ready to be competitive. I’ve got rubber bushings still (I think) but coil overs front and rear, a big sway up front (none in back) it’s a pretty stiff ride.

Funny thing is it runs pretty neutral, with a much different setup than my old narrow body race car, I guess that’s what tire width does for you.

[infraredcalvin]

one cam is 180 out of time,,,

Funny you mention this! Jeff at Aase thinks it’s a timing issue as well, but he thinks it’s due to flywheel marks being off 30 deg - but I think that was before he knew I have a vellios 915 in there.

[Justinp71]

I’m dropping off at Aase tomorrow, hopefully some answers shortly…. If anything it’ll help me reach a baseline.

Cool!

Does your car stay cool on the track? I had to open up the front of the body alot more than you to keep my temps down, but I am also running the stock GT front oil cooler.

Also how is your rear suspension setup? do you like it? Mine seems a bit soft and feel like the trail arms move some. I'm probably going to do the Rebel racing rear bushings like I did in the front.

Car keeps its cool so far, but without proper shrouding it appears it is really inefficient. If I make it to Fontana in aug, that’ll be the rapture test (last year it was 114 in the pits). So far my gauge is telling me the hottest it’s gotten Ian 100 deg C (212F). If I close up the hood though, I’d bet I don’t have enough exit area in the floor…

Suspension seems ok, tires are old Toyos, they seem a bit unpredictable, but prob cause they are aged out, right now these are the last of my worries, I’ll replace with new A052s when I’m ready to be competitive. I’ve got rubber bushings still (I think) but coil overs front and rear, a big sway up front (none in back) it’s a pretty stiff ride.

Funny thing is it runs pretty neutral, with a much different setup than my old narrow body race car, I guess that’s what tire width does for you.

Cool. I've noticed to me it seems when you go from 205's to 225's in the rear the car does become more neutral, but there are obviously many factors that play into it.

Also consider the BFG Rival 1.5S tire, I'm not saying its better because I don't really know but I'm running them now and they are gripping great and have great wear so far. Only 2 track days on them, but I also drive the street and drive to the track.

Cool you have coil-overs in the front. I've heard that gives more options for spring rates, amongst other things I would think.

[infraredcalvin]

Got a great report back from Aase this afternoon, timing was off a bit. Timing at idle was set at 8-9 deg adv, then at 3k up to 25-26 ish, then from 3k-8k was retarted back 7-8 degrees for total advance of 17-18 deg. So he pushed it back up to 26-28 deg and he said it definitely woke her up. So next step is to pick her up, continue tweaking/driving, then take to dyno for final tune. No carb changes, he felt I had her in a good spot. At least I was on the right track….

Not sure he found 100hp, but I’m hoping he woke up at least another 50hp. We’ll see what the butt dyno says tomorrow.

[Justinp71]

Well that is good. That should really help the throttle response too. Get a plate on it so you can test it on the street! Should be super easy since its smog exempt.

[infraredcalvin]

It does have a plate, I drove it from the shop to work, then home, unfortunately traffic kept me from opening her up much, but she now breaths easily past 5k rpm.

Time for some tweakimg!

[Justinp71]

It does have a plate, I drove it from the shop to work, then home, unfortunately traffic kept me from opening her up much, but she now breaths easily past 5k rpm.

Time for some tweakimg!

Cool! So when is the next track day?

[infraredcalvin]

Not till early August, CA speedway in Fontana. Should be a hoot.

[infraredcalvin]

@Justinp71

How are you tuning your carbs? For some reason the voodoo of “listening” for the sweet spot is lost on me. Since going to Aase, my car runs much better, but I still feel there’s much left on the table with some tweaking.

I have an afr logger I’m going to set up this week and I’ll post results for thought/comment here.

Any additional thoughts are welcome, but not expected till I get some data posted.