New Vette Owner & Plenty of Questions

10-24-04, 06:21 AM

Just picked up my '85 hatchback Friday. She sure is purdy!!! I'm 54 and this is my first Corvette. Never thought I'd own one! Now for the questions:

1. What's the best service manual to have in the garage?

2. It's an automatic, around town, is it best to use "drive" or one of the other gears?

3. Haven't been able to identify the exhaust system. To me, it looks like "straight pipes" with no mufflers. She's got spunk, but perhaps a bit too loud. I've spotted lot's of systems for the "86+ but few for the '85. Any recommendations?

4. Any special "characteristics" of this year that I should be aware of, or a web site to visit that can tell me more about this year?

Man, am I looking forward to enjoying this car. It's got 45K on it and looks to have been owned by a true enthusiast. Clean and maticulously cared for.

Thanks in advance for the assistance.

Norm
Galloway OH

MsSchroder · 10-24-04, 07:22 AM

Norm,

Welcome to the CAC and congratulations. It sounds like you got a sweet car.

Post some photos and I'm sure some C4 owners will help you identify the exhaust, and help out with your other questions.

Tammy

Mart · 10-24-04, 09:24 AM

Welcome Norm

As far as the service manual goes, I use the factory service manual and the haynes.

If you post some pics we might be able to help out with the exhaust questions.

I have found this place to be the best source for any problems or help needed, this is the best forum I have ever been on, it's clean, well organized and no jerks creating bad threads.

Remember to wave

Mart

c4cruiser · 10-24-04, 10:25 AM

Congratulations on your new baby!! Hope you get lots of enjoyment from it.

The best service manual is the set from Helm. You can get them at www.helminc.com for about $100 and they are the real GM service manuals. The Haynes or Chilton's books are much too generic to be of real help. You can also find them on eBay from time to time, but some are used and may not be in good condition.

You can leave the tranny selector in either the OD or D position but I prefer to leave min in D at speeds below about 45. Doesn't seem to hurt fuel mileage and kickdown response seems to be quicker (not that I do that a lot....)

The exhaust sound like "muffler eliminators" and lots of folks use that trick to get a sound that Vette's should have. A stock exhaust system is very quiet to the point of boring. The one's I have heard are fairly quiet during cruise speeds but sound great at full throttle.

With only 45K on the clock after 20 years, you might want to check all of the fluids in the car. Consider changing the differential fluid (don't foget the GM posi additive!), have the tranny flushed and add a new filter, new ethlyene glycol coolant and a brake fluid flush using a good grade of DOT3 fluid. Carefully inspect the coolong system hoses if they appear to be original.

You can find information about the 85 at the CAC Model Center At the top of the main page, go to to the "Tech Center" button then go down and click on "Model Center". In the new window, select "1985" from the C4 list on the far right side of the page.

NevadaJim · 10-24-04, 10:41 AM

Welcome aboard and congrats on the new Vette. You've come to the right place when it comes to questions. Although I don't have mine yet, I've seen the helm's manuals and agree they are one of the best investments you can make.

As far as exhaust, you'll get lots of oppinions, I personnally like the Flow Master Force II's, nice sound but not too loud inside the cockpit when cruising.

Cant' wait to see some pics

10-24-04, 08:04 PM

Thanks for all the encouraging responses and suggestions.

Regarding the exhaust - I have taken some pics and will attempt to post them here.

Two other issues surfaced today when we took our first "long" ride. 1) Brake fade in the pedal and then hard when reapplied. Think I read something in the tech section about this. 2) Lack of response when cruising around 55-60 and step on the gas - seems to bog down and accelerate slowly.

Anyway... I'll see if I can get the pics attached.

Thanks again,
Norm

Mart · 10-24-04, 11:02 PM

Looks like muffler eliminators with LT1 tips, I can't quite see but is there no CAT??

Vettefan87 · 10-24-04, 11:38 PM

It just looks like two straight pipes all the way back. Is that what your running, or do you still have the front Y with the precats?

Justin

Edmond · 10-24-04, 11:57 PM

A Corvette being too loud? Nah!

Flowmasters are pretty loud and they do have quite a bit of resonance, so you may want to stay away from those. I know Borla makes a system, stainless steel and IIRC, it also has a million mile warranty. They're in the $500+ area for a pair of mufflers.

I use the Haynes manual and it is pretty generic.

taegdh · 10-25-04, 09:34 AM

I also have an 85 with an automatic. I just drop it into Drive in town but on the Interstate or in the country, where I can maintain a constant 50+, I push the lever forward to the OD area so it goes into Overdrive. The 700R4 is an excellent transmission, just do the proper maintenance.

The HELMS manual is a necessitity if you do fairly deep work. If you aren't planning on doing any extensive work, you can get a Haynes for less than $20 at many outlets such as Wal Mart, K-mart, Pep Boys, Auto Zone, etc...

A good thing about the 85 is it is the BOSCH TPI and not the Crossfire as used on the late C-3s and '84. There are a few things I've had to watch for, EGR staying open, thermostat staying closed, but I got my hands on a low mileage gem.

Check your weather stripping routinely.

As previously stated, looks like someone put "muffler eliminators" with LT1 tips on. They look pretty sturdy, so if the rumble doesn't bother they should last longer than your tympanic membranes.

BUT, the mufflers beside reducing the volume of sound provide a certain amount of back pressure, (not too much but some) which actually helps the engine breathe. So you may have too much scavenging of exhaust. This in turn causes lack of low end performance, stumbling like it's choking for air. Exhausts which have been altered as yours is, are designed for operation at a higher rpm, and the torque curve doesn't start to really build until you're half way to redline.

You didn't mention, but does this vehicle have headers or conventional exhausts forward of the catalytic converters? Have the catalytic converters been removed? (I couldn't see from the view in photo 1.)

The reason I ask is, in various jurisdictions, you have to go for annual or biennial inspections, which frequently include emissions. The emissions test without a catalytic converter could be a difficult prospect. Some inspectors may fail you and demand you replace the complete exhaust. That is an expensive proposition. Lets hope not!

NevadaJim · 10-25-04, 10:05 AM

Quote:

Originally Posted by nmacdonald

Thanks for all the encouraging responses and suggestions.

Regarding the exhaust - I have taken some pics and will attempt to post them here.

Two other issues surfaced today when we took our first "long" ride. 1) Brake fade in the pedal and then hard when reapplied. Think I read something in the tech section about this. 2) Lack of response when cruising around 55-60 and step on the gas - seems to bog down and accelerate slowly.

Anyway... I'll see if I can get the pics attached.

Thanks again,
Norm

The brake fade could be from a couple of different sources, calipars or master cylinder would be my first bets. Check you brake fluid level, if it's low the next thing I'd check is the calipers. Look to see if you can see any leakage. One good place to check is the inside tire walls, normally if a caliper is leaking you will see little streaks of fluid on the tire walls projecting from center to outside. If they check out, I'd start focusing on the master cylinder.

Others here can provide advice on what else to check for, as well as your lack of response at 55; might just need a good tune up.

10-25-04, 11:00 AM

Looks like it's stock system prior to cats. There are two cats about mid way on the exhaust system. The exhaust tips have multiple perforations.
If anyone has part #s for new exhausts, that would be helpful. Corsa doesn't seem to list anything for '85 with the L98 engine. Some one mentioned the Borla IIRC which I'll assume is a model number not a part number.

Will check on the other brake issues and engine performance issues. I've got an inquiry in to my dealer to see if they can pull service records based on VIN number.

Back to exhaust - I don't mind the sound and yes, the system looks VERY STURDY, but I do mind the lack of throttle response in that mid range.

Geez, you guys are very friendly and helpful. I really appreciate everyone's feedback!

MacD

RonJ · 10-25-04, 09:34 PM

Welcome to the club, hope you enjoy your 85 as much as I enjoy mine!!

My exhaust consists of the stock catylitic converter (single unit, two flanged inlets, two flanged outlets), into the pipes and dump out of 2 1/2" outlets. Some may find it loud, I don't, I enjoy the sound!!

Have you tried Ecklers or Mid America? Ecklers shows a system, pricey mind you.

The L98 is a good, torquey engine, it should pull strong for you at almost any speed. Overdrive at 70 mph, she will run there all day with lot's left for passing.

Mind you, another 100 HP might be nice too.......

.

Good luck with your baby, I'm sure you will enjoy it!!

Ron ...

WhalePirot · 10-25-04, 11:01 PM

Welcome to the world of Vettes and the forum! Nice to see folks living their dreams! It's what life is truly about, hopefully.

The stock '84 and '85 exhausts are the same and unique, in that they use a single CAT with four-bolt flanges on each end. The later, early C-4s use two-bolt flanges.

As my car is modified and needs them, I have the Helm manuals for '84, '87 and '90 and don't really care to own any others. Over the years, I have found that the 'others' have so little useful information, as to be, well, not useful, to me. Some excellent local libraries have the 'others' that you could peruse before buying.

The brake fade might be the booster. Is is a matter of lack of power assist or plenty of that, but poor braking. Any noises or fluid loss? The boosters were not particularly great in these years and while yours is slightly larger than '84, the '85 is no great shakes. There is a shop in Santa Ana, CA that rebuilds them, but it's not the simplest of jobs. I'd ensure good vacuum and lines to the booster, first, then check your new manual for proper booster testing.

Be aware, the '85 is one-off in a number of areas, that can make some parts quite hard to find. The TPI is the first year of it, as Rich said, and the ECM is unique to that year. Some engine accessories are unique as well. I do have a used rear Y-pipe, should you need a stocker.

Thinking about the throttle response and the brake issue, iI wonder how much vacuum it pulls. The fuel pressure regulator uses vacuum to change fuel pressure; more fuel being needed during accelleration. Again, your shiny new manual and a new fuel pressure gauge will help troubleshoot proper fuel pressure under varying conditions. A vacuum gauge can find low 'suck' and help ID leaks.

MoeJr · 10-25-04, 11:25 PM

I leave my 84 in the OD position all the time and it works fine and I believe that is what GM reccomends.

Your "lack" of midrange power could be that the car just needs to be driven a bit. With only 45k on it it may just need a good extended hiway run with some great injector cleaner. I use BG's 44k in my Vette and it is the best I have found.