Lab results: Castrol GTX vs. Amsoil synthetic
06-26-2008, 08:55 AM
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Lab results: Castrol GTX vs. Amsoil synthetic
I know this topic has been debated to death. But I have some actual lab results that at first glance seem surprising.
Disclaimer: This was a track weekend test. So I would not say these results speak for a daily driven car under normal driving conditions.
B18C1 Full-Race GT28RS kit
ITR Expo 7 & 8
Both test oil came from events at VIR. Both had a total of 300 miles on the oil, with ~115 track miles.
6-8K rev average
~280-300 oil temp
First test: Castrol GTX 10W-30
Note from lab:: We always think it's a good idea to change the oil after you race an engine. Oil is far cheaper than engines and
we've seen a lot of ugly engines that have the oil run too long when the engine is used for racing. That's not what we
found here. Wear from your Honda looks good. Universal averages for the 1.8L are based on an oil run of ~4,200
miles. Most of your wear was close to average after only 338 miles use, so it was a good time to change it out. The
low viscosity wasn't due to any fuel and isn't a big concern. All in all, things look pretty good here.
Holy moly!! So after ~115 miles on track, my oil looked like it came out of a car with 4200 miles on it!!
Second test: Amsoil 10W-30
Note from lab: You can see the differences in this oil from the last that you sampled in the additive package. This oil contains
more molybdenum, boron, and calcium. Moly is an anti-wear additive, while boron and calcium are
detergent/dispersants. Wear was a little lower in this sample but not enough to indicate that this oil works better than
the other. Both came up with slightly low viscosities but both seem to work equally well for you. We see nothing in this
data that would point to any obvious problems developing. We'd use the less expensive oil.
Now obviously this doesn't mean the synthetic is a waste of money for a normally driven vehicle.
This test does not show what happens for an extended period. From all the claims for the synthetics, I would bet that they will maintain and steady viscosity over time whereas the GTX might drop considerably.
But my conclusion would be that I'm not gaining anything by using a synthetic for just a track weekend. For the price, I could change out the GTX twice and it would still be cheaper then a single Amsoil change.
Because of oil temps and that I've spent my oil only after 300 miles, some other test are going to be made.
First, is going to try GTX 20w-50 on the track and run the test again.
My only concern with changing to such a heavy oil is going to be the excess strain it might cause on my oil pump. Any insight or coments would be helpful.
Second, oil cooler.
Mounting location is going to be an issue though. Not a lot of room left.
Also, as inspyral pointed out below, oil pressure may now be an issue.
Or third, stick with Castrol GTX and change before/during/after a event and not worry about it as long as temps don't peak over 300.
Amsoil Data Sheet
http://amsoil.com/storefront/atm.aspx
Castrol Data Sheet
http://www.castrol.com/liveass...a.pdf
Modified by mrlegoman at 12:53 PM 6/26/2008
Disclaimer: This was a track weekend test. So I would not say these results speak for a daily driven car under normal driving conditions.
B18C1 Full-Race GT28RS kit
ITR Expo 7 & 8
Both test oil came from events at VIR. Both had a total of 300 miles on the oil, with ~115 track miles.
6-8K rev average
~280-300 oil temp
First test: Castrol GTX 10W-30
Note from lab:: We always think it's a good idea to change the oil after you race an engine. Oil is far cheaper than engines and
we've seen a lot of ugly engines that have the oil run too long when the engine is used for racing. That's not what we
found here. Wear from your Honda looks good. Universal averages for the 1.8L are based on an oil run of ~4,200
miles. Most of your wear was close to average after only 338 miles use, so it was a good time to change it out. The
low viscosity wasn't due to any fuel and isn't a big concern. All in all, things look pretty good here.
Holy moly!! So after ~115 miles on track, my oil looked like it came out of a car with 4200 miles on it!!
Second test: Amsoil 10W-30
Note from lab: You can see the differences in this oil from the last that you sampled in the additive package. This oil contains
more molybdenum, boron, and calcium. Moly is an anti-wear additive, while boron and calcium are
detergent/dispersants. Wear was a little lower in this sample but not enough to indicate that this oil works better than
the other. Both came up with slightly low viscosities but both seem to work equally well for you. We see nothing in this
data that would point to any obvious problems developing. We'd use the less expensive oil.
Now obviously this doesn't mean the synthetic is a waste of money for a normally driven vehicle.
This test does not show what happens for an extended period. From all the claims for the synthetics, I would bet that they will maintain and steady viscosity over time whereas the GTX might drop considerably.
But my conclusion would be that I'm not gaining anything by using a synthetic for just a track weekend. For the price, I could change out the GTX twice and it would still be cheaper then a single Amsoil change.
Because of oil temps and that I've spent my oil only after 300 miles, some other test are going to be made.
First, is going to try GTX 20w-50 on the track and run the test again.
My only concern with changing to such a heavy oil is going to be the excess strain it might cause on my oil pump. Any insight or coments would be helpful.
Second, oil cooler.
Mounting location is going to be an issue though. Not a lot of room left.
Also, as inspyral pointed out below, oil pressure may now be an issue.
Or third, stick with Castrol GTX and change before/during/after a event and not worry about it as long as temps don't peak over 300.
Amsoil Data Sheet
http://amsoil.com/storefront/atm.aspx
Castrol Data Sheet
http://www.castrol.com/liveass...a.pdf
Modified by mrlegoman at 12:53 PM 6/26/2008
06-26-2008, 11:32 AM
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Good info, and wow those are some high oil temps 
It's usually debated that oil coolers can cause a drop in oil pressure which is pretty vital for turbo and VTEC operation, but in your case it'd probably be worth considering. A higher viscosity oil will also likely be of some benefit to you, given the beating your setup goes through on track days and how much viscosity oil loses as the temperature rises. You could maybe try a 40 weight oil before going up to the 20w50, and if you're interested in trying a cheap full synthetic with high levels of anti-wear agents(I believe it's ZDDP - zinc dia something-or-other phosphate), I would give Shell Rotella T synthetic 5w40 a try. It's about $16-17/gallon and you can find it at Kragen/Checkers/Parts America stores and Walmart. Check the label and make sure it's the CI-4 standard oil, since the newer CJ-4 "Triple Protection" stuff has its zinc levels reduced to conform with newer emissions standards. It might also be good to run a lower viscosity oil, like a 30 weight, in the winter for better start-up protection, and switch it out for a higher viscosity in the summer.
It's usually debated that oil coolers can cause a drop in oil pressure which is pretty vital for turbo and VTEC operation, but in your case it'd probably be worth considering. A higher viscosity oil will also likely be of some benefit to you, given the beating your setup goes through on track days and how much viscosity oil loses as the temperature rises. You could maybe try a 40 weight oil before going up to the 20w50, and if you're interested in trying a cheap full synthetic with high levels of anti-wear agents(I believe it's ZDDP - zinc dia something-or-other phosphate), I would give Shell Rotella T synthetic 5w40 a try. It's about $16-17/gallon and you can find it at Kragen/Checkers/Parts America stores and Walmart. Check the label and make sure it's the CI-4 standard oil, since the newer CJ-4 "Triple Protection" stuff has its zinc levels reduced to conform with newer emissions standards. It might also be good to run a lower viscosity oil, like a 30 weight, in the winter for better start-up protection, and switch it out for a higher viscosity in the summer.
06-29-2008, 11:03 PM
#4
Thanks for posting this up.
Should definitely note for others reading that this is a turbo engine, so its track miles differ from an NA engine.
How did your oil temps and pressure change over the course of the main straight, back straight, and uphill esses?
Should definitely note for others reading that this is a turbo engine, so its track miles differ from an NA engine.
How did your oil temps and pressure change over the course of the main straight, back straight, and uphill esses?
06-30-2008, 08:27 AM
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Re: (Aquafina)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Aquafina »</TD></TR><TR><TD CLASS="quote">Thanks for posting this up.
Should definitely note for others reading that this is a turbo engine, so its track miles differ from an NA engine.
How did your oil temps and pressure change over the course of the main straight, back straight, and uphill esses?</TD></TR></TABLE>oil temps actually would drop a few degrees on the main straights, even though I was full throttle. These where the only times too I would actually drop my eyes to look at the gauges. But in general, the oil temps did not vary for more then 5 degs around the track.
I did not measure pressure changes.
Should definitely note for others reading that this is a turbo engine, so its track miles differ from an NA engine.
How did your oil temps and pressure change over the course of the main straight, back straight, and uphill esses?</TD></TR></TABLE>oil temps actually would drop a few degrees on the main straights, even though I was full throttle. These where the only times too I would actually drop my eyes to look at the gauges. But in general, the oil temps did not vary for more then 5 degs around the track.
I did not measure pressure changes.
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