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Adding performance parts - incrementally


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I've got a stock 1985 non intercooled flatty. My mechanic says I should look into a Cat Back exhaust and a cold air intake. Any recommendations? It looks like the cold air intakes I've seen are universal fit.

http://www.discountairintake.com/store/?N=0&VN=4294967243+4294966732+4294966589+4294967247+4294966614&Nr=AND%28OR%28category:Air%20Intake,%20category:Fuel%20Delivery%29,universal:1%29&Ntt=air+intakes

 

It looks like HKS has a Cat Back, anybody running with any others? I had the catalytic converters replaced about 10 years ago. But the last time it was tested it failed emissions. Now that I've got classic car tags I no longer get tested but I'm wondering if they should just get removed.

http://www.gripmotorsports.com/ps~pnd~turbo_exhaust-hks.html

 

I'm not looking to throw more than $500 at a time every few months or so.

But cold air in and more air out sounds like a good idea for a hot turbo. I'm guessing it'll help.

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If I don't have to worry about emissions, I guess I should go without a Catalytic Converter. Will this hurt the car? Do I need any special modifications to do that? I see Top End Performance has some options.

http://www.racetep.com/bpipe.html

It will not hurt the car it will free up power and better mpgs too..

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Haha, yep... intercool it. I know you just spent a long time finding a non intercooled housing, but intercooling the car makes a huuuuuge difference. Everything pretty much bolts on. You can get an intercooled compressor housing easily too that'll fit right on your replacement turbo.

 

-Robert

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My mechanic seems more courageous than I. I asked him about adding an intercooler and he said it was just an extra radiator and some hoses. Not having another starquest to look at, or even get an idea what I'm getting myself into, I'm not as brave. I just don't know what all I truly need to go inter cooled. Is there a post on this subject anywhere on this site? I'd like to do it if it'll make my car more reliable and last longer. I want to keep driving it as long as I can.
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Take a look at this:

 

http://www.starquestclub.com/forum/index.php?showtopic=76827

 

I suggest you do work yourself on your car, that way you will know how to repair it when the time comes. It is not extremely difficult, and we are here to help you... don't be scared!!

 

-Robert

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I would add a hot coil, bov and a performance muffler after you'd added the down pipe. Then you could go with some larger injectors and later year mas before adding a bigger turbo. My friends tell me and the boards here at SQC tell me air/fuel and exhaust are key and you don't have to spend alot of money.

 

On my flatty I wanted to keep it original by adding just a hot coil, upgraded the fuel system (pump, filters), bov, gutted the precat and added a performance muffler. When the original turbo dies I will go with a 14g or small 16g. But I'm keeping a 12A on hand for the originality factor.

 

Cheers,

 

SLim Jim

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Hot coil?

 

Best performance muffler is no muffler at all :D

 

Also before you just go up and grab bigger injectors you will have to have a way to tune your afr (cheapest and easiest being gm maft)

 

But with that you also need a wideband...i think your looking at $400+ without the cost of even the injectors :S

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Hot coil?

 

Best performance muffler is no muffler at all :D

 

Also before you just go up and grab bigger injectors you will have to have a way to tune your afr (cheapest and easiest being gm maft)

 

But with that you also need a wideband...i think your looking at $400+ without the cost of even the injectors :S

 

Bosch Red Coil is referred to or MSD Blaster is referred to as a "hot" coil in many areas. Correct me if i'm wrong?

And on the muffler bit, great no muffler but I wouldn't consider this to be road worthy either. And yes a wide band is a good investment after the basics and it you plan on throwing alot of fuel and boost into the equation.

 

;)

 

Cheers,

 

Jim

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First things to do before performance mods is to give yourself the ability to monitor the fuel pressure, and the AF ratio with a fuel pressure gauge visible while driving, and a wideband O2 sensor. Those are a must at least before turning up the boost, or adding too much fuel, etc...

 

You can however put a new 2.5 or 3" exhaust on it with a good downpipe. You can have the bung for the wideband welded on about 18" down from the top flange on it. Plug the bung until you get the wideband, or put it on with the exhaust. The exhaust you can get from MK1 or others on this site who sell them. I would stay away from TEP unless you can't find it elsewhere. And post up here about it before ordering it from them. There may be someone here who has a better option.

 

Add the K&N filter, and remove the cardboard star from the Mass Air Flow Sensor. Those mods alone will wake it up considerably without touching anything else. If you go any more than that, look forward to heavier maintenance issues such as replaceing the head, etc... Before going forward with anything else, you really need to do all of the little things that many don't and regret, like changing the main engine bay fuel filter, and cleaning all of the others. I've never seen a bad in-tank filter, but you should check it. The little cone fuel filter before the pump almost always needs cleaned out. The screens above the injectors need cleaned too, and maybe the injectors themselves. It is always a good idea to pull them and replace the injectors seals when reassembling after you get the injectors professionally cleaned.

 

Then fix the head stud issues that are causing the exhaust leak on the rear most stud at least. You can maybe even decide to tackle that when doing the exhaust. Pull the ex manifold and cut the webbing and then have a machine shop put the manifold head flange on a belt sander to plane the ports smooth. Repair any bad or pulled studs with helicoils and replace the manifold. Chances are good the valve springs are old and worn out and will float the valves much over 4800RPM if not sooner. Replace them with some Schneider 6610's from Dad on this site. He also has many of the little parts you will need and gaskets, etc.. You can put a performance cam in it if you are into that. It will normally give you a good increase through the mid range to help the boost make more power.

 

Replace the timing chain and do a balance shaft elimination on it if the engine is much over 150K miles. You can simply replace the timing chains and keep the shafts in, but they are problematic and may seize up to lose oil pressure at the worst possible moment to basically grenade the eninge right there, or worse, the shafts stick a little here and there to slowly kill the engine from intermittent lack of oil, and metal in the oil, etc... You can put new balance shaft bearings in there, but that really requires a pro to do it, or someone very experienced to help you. I say just remove the shafts.

 

Then replace the radiator or at least get it rodded and or make sure the cooling system is top notch. It is best to run a 180 degree T-Stat usually too. I've experimented to both extremes from stock 192 to no T-Stat, and a 180 usually works well in most any circumstance.

 

After you have an intercooler on there, chances are you will need a new clutch because with an intercooler you can raise the boost while monitoring the fuel pressure and AF ratio as always. The reason to monitor the FP is so you can see why the AF goes lean when it does. Many times the stock pump can't keep up, so you could just change the pump to a Walbro 255LPH while you are checking the filters back there. I like to cut the trunk floor to get at the pump, but many like to remove the gas tank and do all of the cleaning maintenance of dirt and rocks there when the do the pump. After intercooling it, you should have a way to adjust the AF ratio so you can safely raise the boost. A cheap but much less effective way is to get an adjustable FPR to simply raise the baseline FP to say 45 - 50 from 39 or so OEM. The better, safer, and only good way to do it if you plan on increasing the intercooled boost, is to put a GM Mass Air Flow Sensor on it and an aftermarket MAF-Translator that allows you to adjust the fuel for idle, cruise, and Wide Open Throttle. With that, you can raise the boost a bit more than with an adjustable fpr, and more safely too. Like maybe to a maximum of 16 PSI or so with the stock turbo and injectors.

 

After doing all of that, she should fly with a Viper from 80 - 130 MPH, and top out around 160 or so if the suspension is sound enough.

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That "cold air" intake part don't pay attention to what he says if he thinks an intercooler is a radiator and hoses. The air can draws in cold air already from the fender apron and its open at the bottom. When they take the air can off and hang a filter in the engine bay its no longer cold air intake now its HOT air intake and it draws in hot air while driving too and if the air blows up against the air filter it screws the flow and how the MAF reads the air and causes more problems. Until you are at highway speeds that opened or removed air can doesn't get you just "cold air". Leave your air can there and let it suck in the air from where it does now just get a good filter. Your ECU wasn't made for adding in much more fuel like an intercooled ECU. The intercooled ECU won't plug in to your harness the pins are different locations. I'd send the injectors out to be cleaned first. Drive it like it is and enjoy it and getting some decent fuel economy. When you want to do all those changes just get a different car there's to many things to change.
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  • 1 month later...

As for the mods you already listed,

 

Pick up a K&N replacement filter, and neatly drill the lower part of the can (below the lid) full of holes with a circle saw.

 

I had the HKS catback, it's OK, it fits well but is about 2.4 inches diameter and the muffler looks a little funny. The construction is very good and it bolts right on. You can also grab a muffler you like and go to a decent shop and have them bend up an exhaust for you, it's pretty basic.

 

Beyond that>

 

Look into picking up an intercooler setup from a later year car, should be easy.

 

>Get the front of the exhaust, the downpipe and the "B-pipe", which normally contains the under-car cat. You can get the downpipe, and then get the rest of the exhaust made with a universal cat (or not) and your muffler choice for probably less than $150 plus the cat and muffler. Top End Performance makes a good 2.5" downpipe, but Mookeeh (101 propose on eBay) makes the best one, by FAR.

 

> Replace the tired suspension and drop it a couple inches, it will dramatically improve the handling and stability.

 

Good place to start.

Edited by Fuze
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