Druepy

I am starting this thread partly to introduce myself but also so that I can spare you guys from me starting a thread every 5 minutes. My name is Drew and I have an addiction to Porsches. After sending almost a year away from the car I am back to tinkering and I hope to be active on the forum.



I bought this car 2 years ago and since I've bought the car I have done a few maintenance projects and continue to try to solve existing issues.



Right now the main issue with the car is that, in the words of my mechanic "the car just isn't as fast as it should be". The car seems slightly sluggish and is only reaching ~1.7 bar at WOT. The exhaust and intake have been combed over for leaks so I am now turning my attention to the waste gate and catalytic converter. Whether the issue is a leaking WG and plugged cat I'd like to diagnose the issue before I go throwing money at the wrong thing. I am thinking about pulling the WG out to see if it is leaking.



1986 951 blk/blk
93k miles
Basically stock with Authority chip

bumflick

Drue, Welcome

I have an 86 as well, purchased about 4 years ago with 119k miles.

my car had the same not as fast as it should be problem, but it made even less boost than yours. I suspected vacuum leaks, exhaust leaks and bad wastegate and leaky turbo. Replaced a bunch of stuff, and it is much better now. Currently trying to cure a high idle.

Good luck. Lots of very knowledgeable folks in this group.

Malcolm

Druepy

I'm really looking forward to experiencing the car at full boost. How high is your car's idle?

Druepy

I just went out and clamped the actuating line on the waste gate. My understanding is that with the spring in the stock WG the exhaust will begin bleeding at ~1.75 bar (~11.5psi). With it clamped the max boost I saw was around 1.6 bar. It might be my imagination but the car felt a little more peppy with the line clamped.

Being approximately 1.5 bar less than expected is a loss of 20% boost. This indicates that the WG is leaking or has a weak spring. This is one of the reasons the car seems sluggish. Looks like a Tial is next in line for the car. Tial is the brand I have seen mentioned time and time again in old threads I found through research but if that is dated information I like to hear it.

rlm328

Austin has a very large and a very knowledgeable 951 community. Keep an eye out for the next DE in Texas. You do not necessarily need to participate but it will give you the opportunity to meet the people who can help you out.

Druepy

I actually just met a 951 owner that lives near me who also happens to be a pca driving instructor. He told me about a DE at COTA next month so I think I'll probably go and check it out.

Druepy

Friday night was the first time here in Austin that it go cool over night and when I was texting the waste gate the car was vibrating a lot more than usual. The car just feels a lot more raw than previously. On my last car I had hard street urethane motor mounts and this vibration feels very similar to how that car felt except that it really becomes prevalent at 3k rpms and up. Additionally, the car seems more studdery at low rpm first gear starts.

My initial though is that the cold snap pushed the mounts over the edge? I just got in there and found these green mounts which I can't seem to find anywhere online. I found one rennlist thread that mentions OEM green mounts but that's it. I took some pictures of them because I can't tell if they are bad. They have a nut so I'd imagine they are an early design style. I also saw some stuff about clutch engagement problems and hydraulics causing vibration. The clutch was done about 1k miles ago. I'm not sure if that would make a difference.

Passenger side mount

Druepy

Clark's garage mentions that when diagnosing bad engine mounts the "Vibration at idle (assuming balance shafts are properly aligned). Vibration will usually decrease noticeably or disappear when engine rpm is increased to around 1500 rpm." which is just about the opposite of what my car is doing.

The car feels just as strong mechanically as last week and I haven't had any warning lights come on. It isn't related to the wheels/suspension because in neutral the vibration subsides. Maybe it is transmission/clutch related.

Edit: It could be the balance shaft belt. What's weird is the balance shaft belt was just done less than 100 miles ago so if that's the issue that'd be strange. The pulley could be off but this was done by a mechanic and this issue didn't appear at the same time that I received the car.

My headlights were horrible and there was little to no difference between high and low beam. Just installed these goodies and can wait to see the difference tonight.