Your 951 MPG

[mivporsche]

I bought a 1988 951 last Oct. I saw some posts (not here) about how unreliable these cars are, so I decided to make the car my daily driver for one month. My car has 145k miles on it. She has 248 rwhp.

I did have a small coolant leak, an electrical clitch or two, and a pesky sunroof cable problem, but nothing that took longer than 1 hour to fix, but overall, the car has been great.

My route to work is 50 miles one way. The speed limit is 50mph, so I drive at 60. It is mostly hwy miles. My MPG? 27 to 28 MPG! I find this as a pleasant suprize. I have learned (from this forum) that the best mileage comes from a brisk acceleration to speed (full throttle short shifting) then anticipating stops by getting off the gas pedal asap (I get it out of gear too). My only concern is I used 1 qt of oil for 2008 miles.

So is this normal mpg? Normal oil comsumption? What is yours?

[nynor]

mine got about 25MPG on a road trip to portland and back, but we were going close to 90 the entire way. mine has very little oil consumption, but it does have some, maybe half of what you experienced. there will be some oil blowby at the turbo.

[eyeballkid]

I'm brand new to 951's as well, but that's the mpg I have been seeing when I'm not deep into boost. Bye the way, where was your coolant leaking from?

[nynor]

i know that you are asking movporsche, but i had one at the waterpump where the plastic piece bolts on for the turbo waterpump.

i've also seen the end-caps separate on the radiator, i've seen them overfilled, and i've seen the waterpumps fail and/or the water pump gasket.

i think you need to start by taking the belly pan off so that you can see the general area where the leak is.

[mivporsche]

My coolant leak was on a brass fitting behing the overflow tank. No plumber's tape on it. Also, I overfilled it so I could smell coolant, but no leaks on the floor. I was lucky. My mpg is more like 26 when on the Interstate going 80mph.

[lleroyb]

I typically get around 23 mpg around town and as much as 29 on the highway. I ran over to Montana and back last summer and got 27 for trip, little of which was below 75-80. There were a couple of runs with a late eighties 'vette.

Lou

[AaronM]

I will second Lou and his 23 mpg in town and 27-29 on the freeway. These cars get surprisingly good mileage when you stay out of boost.

As far as oil consumption, the rule of thumb for most cars is that 1 quart/1,000 miles is the point at which one should start to worry. Less than that and it usually costs a lot more to find and fix the issue than it's worth. You'll burn more the more you get into boost because as nynor said there will always be some blow-by at the turbo. My car doesn't hardly burn any at all, but it's also not on the original turbo, so its seals are fresher. Overall I probably burn a half-quart every 3,000 miles.

[trivgar]

8city/15hwy

[AaronM]

Originally Posted by trivgar

8city/15hwy

Something is seriously wrong with your engine, you're driving with the emergency brake stuck on, or you're permanently stuck in 2nd gear.

Even a heavily modified car should be doing much, much, much better than those numbers.

[Techno Duck]

I saw 25mpg on the roughly 250 mile round trip between Pocono and Long Island. On the actual track i think i got something like 8mpg . I use mine as a daily driver also during the summer. I usually do a pretty even split of highway and around town, it works about to be 20mpg roughly.

[trivgar]

Engine runs awesome. I expect it's the rich tune and 75# injectors.

[AaronM]

Originally Posted by trivgar

Engine runs awesome. I expect it's the rich tune and 75# injectors.

That's going beyond a "rich tune" because there's no way that the car should be getting only 15 mpg highway. These cars aren't even in boost at steady-state highway cruise. You need to lean that sucker out a lot for off-boost operation.

Of course, I don't know fully what you've done with your car so I probably ought to shut up before I prove myself stupid. I've just seen even 3.0 litre custom Turbo jobs that do better than 15 highway.

[gpan951]

I use a 1988 Turbo S as a daily driver with the following mods : Vitesse MAF, #75 injectors, 17psi boost, stock turbo. I have 282rwhp.
I get 19mpg with a mixture of 20% city 80% highway driving with the a/c on.
I get 23mpg 100% highway with the a/c on, constant 70mph.
Bonestock, I would get 23/26mpg respectively.

[trivgar]

my engine is lightly modded. Afr is like 12:1 at cruise. I'm eventually going to have it at 15:1 but I've been having a lot of problems with my car. Unrelated to the engine.

[2Tight]

I usually get about 25mpg on runs or trips where I can measure a full tank. I have no idea what it is around town though. This is with the K26-8 car and I don't drive slow or girly like at all.