10W40 to 10W30

bab98cobra

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I have a 98 cobra with a S-trim. New motor has about 2500 miles on it. I have been putting 10W40 castrol edge in it. I want to change to Amsoil or RP. I want to go with a 10W30. Will there be a problem going to a 10W30? I looked on both web pages and it seems like they both have a few types off oil to pick from. Whats the best type for each? I drive the car most of the year. I also have a D&D viper spec T56. What is best to put in it?Thanks for any input.
 

UnleashedBeast

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It all about oil pressure. Too much is not better.

Amsoil has a few different grades of 10W-30, but I'm only going to talk about two.

Amsoil ATM 10W-30 Signature Series and RD30 10W-30 Dominator

Which to choose depends on your use of the car.

ATM 10W-30: Use for everyday driving, aggressive driving, up to 15,000 miles/ 1year.

RD30 - Use for aggressive engines that are not driven daily, are very high HP, possibly using E85, or serious forced induction applications. Use for 5,000 miles or 6 months.

For your Viper spec transmission, you will love this stuff.

Amsoil ATF
 
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Jimmysidecarr

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I have a 98 cobra with a S-trim. New motor has about 2500 miles on it. I have been putting 10W40 castrol edge in it. I want to change to Amsoil or RP. I want to go with a 10W30. Will there be a problem going to a 10W30? I looked on both web pages and it seems like they both have a few types off oil to pick from. Whats the best type for each? I drive the car most of the year. I also have a D&D viper spec T56. What is best to put in it?Thanks for any input.

On the Royal Purple side for your 1998 SVT Cobra Mustang S trim we recommend the following:

Engine: Royal Purple SAE 5W-30 (part #01530, quart bottle) or Royal Purple SAE 10W-30 (part #01130, quart bottle)
or for a significant upgrade in protection and performance Royal Purple HPS 5W30 (part #31530, quart bottle) or ;-):thumbsup:Royal Purple HPS 10W-30 (part #31130, quart bottle); 6.0 quarts;

Engine oil filter: Royal Purple Extended Life Synthetic Oil Filter (part #20-820);
(in stock at most Pep Boys and able to be ordered online through many outlets)

Manual Trans: Royal Purple Synchromax (part #01512, quart bottle); 3.3 quarts;
(T-45)

8.8” Differential: Royal Purple Max Gear 75W-90 (part # 01300, quart bottle); 1.9 quarts;(includes the limited slip friction modifier);

Power Steering: Royal Purple Max EZ (part #01326, 16-oz bottle) or Royal Purple Max ATF (part # 01320, quart bottle);

Due to the HPS being a new product last year, you are not likely to find it on a local store shelf just yet.
However a special order can be done at your local NAPA and O’Reilly’s.
Eventually HPS should be available at Advanced Auto, Carquest and Pep Boys as well.

If getting it locally does not work out it is definitely available at the following online outlets:

Lucky7trucks.com: HPS High Performance Street Oil - Lucky 7 Truck Accessories
Summit Racing: Royal Purple at SummitRacing.com: synthetic motor oil, coolant additives, gear lube, transmission fluid, assembly lube & more
Jegs: Royal Purple 31130 Royal Purple HPS Street Motor Oil
Amazon.com
Pace Performance: Pace Performance
 

UnleashedBeast

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I would think an Amsoil filter is best.

The Amsoil EaO EaO11 and Royal Purple 20-820 oil filters are the same. Either is a far superior choice to any other filter you could buy.

As Jimmy said, Royal Purple HPS or XPR are both excellent lubricants. I'd use either without discretion, and I'm picky!

Still waiting on that awesome deal on XPR, but was told I'm not special enough for that super secret elixir. :-D
 

SID297

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Did your engine builder recommend a specific grade? I'm thinking about giving RP 5w40 HPS a try. It's some serious stuff.
 

bab98cobra

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I did all the break in with 10W30 and after the break in he said I should run 10W40. Thats why I was wondering if it would be a big deal to just run 10W30.
 

Jimmysidecarr

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Did your engine builder recommend a specific grade? I'm thinking about giving RP 5w40 HPS a try. It's some serious stuff.

Travis, just keep in mind the diesel add pack in the ACEA B3 SAE 5w-40 is not a CJ-4 API additive package. It is for small displacement light duty passengers car type diesels and though it does have Synerlec and an incredibly robust formulation the HPS 10w-40 would be a better "post warranty" selection.

Unless you need the 5w cold flow for something that needs a 40 weight.

What were you thinking of putting 5w40 in?
 

SID297

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Travis, just keep in mind the diesel add pack in the ACEA B3 SAE 5w-40 is not a CJ-4 API additive package. It is for small displacement light duty passengers car type diesels and though it does have Synerlec and an incredibly robust formulation the HPS 10w-40 would be a better "post warranty" selection.

Unless you need the 5w cold flow for something that needs a 40 weight.

What were you thinking of putting 5w40 in?

Crap, I meant 10w40. Got confused with the 5w30 HPS we run in the SVTP GT.
 

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