New 99 RT/10 owner, few questions on issues/coilovers.

[ViperFan1]

Hello all, located in MD and am finally a Viper owner after 25+ years of dreaming. Got a 99 RT10 with 58k miles, shipped it from Dallas. Came with pretty good maintenance history, Venzano interior, ACR stripes, 18" Forgeline ZX3R-6 wheels and stock wheels, and a muffler delete. I got it for a great price knowing I'd have to upgrade/repair a few things here and there.

So far I've done:
-PPI with compression check and fresh spark plugs, had great numbers.
-New water pump, new tires, new coolant, brake, clutch, diff and trans fluids.
-New IPSCO power steering and bracket pulley, along with IPSCO tensioner, idler, alternator, water pump pulley, new belt. IPSCO trans brace with poly mount.
-New engine mounts, two window regulators rebuilt, 3 new speakers, new smooth tubes and K&N filters, and rear window seal, though I had to reuse the current one as the Temple just didn't want to fit. New battery, new key cut and key fob, AC refilled, and oil change/alignment.
-Single DIN 7" Pioneer flip out and up unit for CarPlay/backup camera. Tried a Boss floating screen but it was far too bright at night and had no buttons/knobs for volume/song switch. Backup camera was quite a pain to wire, but definitely helps.
-New LED's in low beam, high beam, backup lights, fogs.
-Corsa catback, initially paired it with stainless Belanger high flow cats, now running a cat delete instead. Upon install I found that I had no oem heat shielding, only an armor blanket from previous owner, so I added the Sticky Shield and HeatShield protection on the chassis/sills, and around the new pipes on sides and around the diff.

Issues I'm currently struggling with:
-Really want to order coilovers to sharpen the handling and ride. Leaning towards BC Racing which I've had on other cars with no issues, but I'm really struggling to figure out the proper spring rate. I understand the 10/12 is recommended, but I see people saying it rides like garbage and that spring rates 6/8 or 8/14 are much better overall. Was also recommended Aldan's but see more negative reviews than good, same with MCS.
-Sometimes at full throttle from low RPM, it stops accelerating around 5k rpm. As if it hits redline/hits a wall before even close to redline. Was suggested maybe a fuel filter or ignition wires or fuel pump?
-There is a whining sound when on the throttle lightly accelerating in 5-6 gears at low rpm when car is hot or ran for 15+ minutes on highway. Say 1500 rpm at 60-80mph. Trans or clutch or diff sound or it may be normal? Especially heard with windows up.
-Odd NVH sound coming from air vents when accelerating. Like a deep whirring sound, not sure if normal. It sounds like a kitchen blender whirring and increases with RPM.
-Hard top has been adjusted to be tight but is still very squeaky. Looking for a good method or rubber liner to add to minimize the noise?
-Come next year I'd like to upgrade to 18/19" or 19" wheels and possibly go to 3.73 or 3.55 gears eventually. Will probably remove the stripes as well.

 

[ninetyninegts]

Hello all, located in MD and am finally a Viper owner after 25+ years of dreaming. Got a 99 RT10 with 58k miles, shipped it from Dallas. Came with pretty good maintenance history, Venzano interior, ACR stripes, 18" Forgeline ZX3R-6 wheels and stock wheels, and a muffler delete. I got it for a great price knowing I'd have to upgrade/repair a few things here and there.

So far I've done:
-PPI with compression check and fresh spark plugs, had great numbers.
-New water pump, new tires, new coolant, brake, clutch, diff and trans fluids.
-New IPSCO power steering and bracket pulley, along with IPSCO tensioner, idler, alternator, water pump pulley, new belt. IPSCO trans brace with poly mount.
-New engine mounts, two window regulators rebuilt, 3 new speakers, new smooth tubes and K&N filters, and rear window seal, though I had to reuse the current one as the Temple just didn't want to fit. New battery, new key cut and key fob, AC refilled, and oil change/alignment.
-Single DIN 7" Pioneer flip out and up unit for CarPlay/backup camera. Tried a Boss floating screen but it was far too bright at night and had no buttons/knobs for volume/song switch. Backup camera was quite a pain to wire, but definitely helps.
-New LED's in low beam, high beam, backup lights, fogs.
-Corsa catback, initially paired it with stainless Belanger high flow cats, now running a cat delete instead. Upon install I found that I had no oem heat shielding, only an armor blanket from previous owner, so I added the Sticky Shield and HeatShield protection on the chassis/sills, and around the new pipes on sides and around the diff.

Issues I'm currently struggling with:
-Really want to order coilovers to sharpen the handling and ride. Leaning towards BC Racing which I've had on other cars with no issues, but I'm really struggling to figure out the proper spring rate. I understand the 10/12 is recommended, but I see people saying it rides like garbage and that spring rates 6/8 or 8/14 are much better overall. Was also recommended Aldan's but see more negative reviews than good, same with MCS.
-Sometimes at full throttle from low RPM, it stops accelerating around 5k rpm. As if it hits redline/hits a wall before even close to redline. Was suggested maybe a fuel filter or ignition wires or fuel pump?
-There is a whining sound when on the throttle lightly accelerating in 5-6 gears at low rpm when car is hot or ran for 15+ minutes on highway. Say 1500 rpm at 60-80mph. Trans or clutch or diff sound or it may be normal? Especially heard with windows up.
-Odd NVH sound coming from air vents when accelerating. Like a deep whirring sound, not sure if normal. It sounds like a kitchen blender whirring and increases with RPM.
-Hard top has been adjusted to be tight but is still very squeaky. Looking for a good method or rubber liner to add to minimize the noise?
-Come next year I'd like to upgrade to 18/19" or 19" wheels and possibly go to 3.73 or 3.55 gears eventually. Will probably remove the stripes as well.

While doing your suspension I would highly recommend doing polyurethane bushings, made the most difference for mine. I did get the Aldan's and they do fine for the money but if I would do it over again, I would get the best I could afford with external adjusters. Maybe others have suggesting on brands or check the forms for recommended coilovers.

 

[white out]

You have done all the great driver mods that really make the car more enjoyable to own and drive.

I think we have messaged about coilovers - feel free to DM me here - but the standard BC rates are a good setup for street use. Very similar to G2 ACR suspension.

Falling on its face at 5k is odd - replace spark plugs & wires (qualitywires.com), also might want to have the injectors sent out to be cleaned.

RE: driveline sounds, check all your u-joints re: the vibration - they can die from age. Check the crank pulley to make sure it is not loose.

 

[haneifk]

Congrats on the dream coming true! Driving it for the first time is such a surreal experience and will put a smile on your face for years to come.

I didn't see IPSCO solid steering rack bushings on your list. Maybe I missed it but I would definitely recommend. I got a 3.73 diff and have been very happy with it. And for all your NVH. These are very noisy cars. Without actually being there it's hard to tell if it's normal or not. I would just keep an eye on it to see if it gets worse before digging around.
If you're planning on tracking the car you'll need a catch can setup and a little sprout for the power steering reservoir cap. Probably a few other things but can't remember off the top of my head.

Lots of knowledgeable people on this forum so you're at the right place.

 

[FuzzyRev]

You and I are in almost the same boat. I just bought my first Viper, a 99 RT-10 with 57k miles, and I'm also trying to judge what I want to do or not regarding certain maintenance & repairs.. You're off to a great start though!

Mine has hit the rev limiter at an indicated 4950 RPM, but I think the tach is just lazy. I'll confirm soon when I strap it to the dyno...

 

[ViperFan1]

Hello all, just figured I'd update as quite a lot of changes have been done. Since my last update I was chasing the 5k rpm limiter and after checking crank sensor, replacing fuel filter, getting fuel gauge to see if fuel pump was an issue and various things like O2 sensors etc, we came to the conclusion that the tach may be slow. The computer hooked up to it shows rpm's at 6000-6100 but the tach doesn't every time, so ordered a NOS tach hopefully that will be the end of that.

The cat delete ended up being not for me. The sound is great, but only for the first hour. While tolerable, the open top with the catless smell had me showering after every drive. HFC's got put back on. Interestingly enough I had found out that they were broken inside after only a few months in, but Belanger was great enough to replace them very quickly.

I've had my detailer remove the ACR vinyl stripes with a full paint correction and ceramic done, still need to do top coat. Learned the car had been repainted, without the best methods, but post correction the paint quality legitimately looks like a better car than anything new I've seen this year. Did have some bad luck with the oem headlights, wanted to PPF them but found out that they were already treated with something that ended up peeling upon buffing, long story short had the headlights rebuilt and polished inside and ou. Removed any interior condensation, and the exteriors look better than ever.

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Also since I've had a full suspension rebuild: BC Coilovers with Swift springs, 10/12kg rates, full energy suspension poly bushings all around, new end links and IPSCO solid steering rack bushings. Same shop also fixed intake manifold gaskets, valve cover gaskets, pcv line oil leak, transmission shifter oil leak and added a Team RXP catch can. Out of the box the car had a nice bit of a drop:

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But ultimately I decided to go 1/2" lower:

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Didn't realize it would settle much more so I will go 1/4" up and call it a day. Already it feels amazing to drive and other than my driveway it doesn't scrape or catch anywhere. The suspension is even more tolerable than my daily driver, a lifted GX460 on 33's (seen in background).

All that's left for this season is a new MGW barrel grip shift knob, not really a fan of the round MGW, and maybe 50% windshield tint. Hoping to find a set of cheap 19's before the summer. Absolute joy every time I drive it.