oil weight = HP

bogan · Apr 18, 2012

Hello Everybody,
I own a 300+hp Saab turbo.

I usually run 5w40 full syn.

I am going to take my car to the dyno and was wondering if I was to change to 5w30 if I would get an increase in HP.
I watched this video on oil and thought it was interesting.
http://www.youtube.com/watch?v=49kETjPZP9Y.

What do you guys think?

Thanks Greg.

Jim Allen · Apr 18, 2012

You might but as with many things, "it depends." Depends on oil temp when the runs are made. If you made a run on 5W40 with the oil not fully warmed up then ran the 5W30 at a blisteringly hot temp, you might see a wide gap. You could do the reverse and see them at about the same level or even higher on the 5W40. I would advise checking your oil temps before doing anything. You may NEED 5W40 on that dyno to keep the engine healthy. Day to day running easy you might not but the dyno will demand the most and without major airflow, the engine will get hot fast.

Speaking of heat, I enjoyed the video but think it was rigged. The last runs on Nulon, the operator put the fan really close to the front of the car, which would help on the power by putting more airflow across the intercooler. I was dyno testing an engine last week, a turbo diesel, where we saw the exact same phenomenon... let the intercooler get hot, you begin to lose power, Cool it and the power goes up. In our case, it was worth 15-20 hp from the first "cool" runs to the last "hot" ones. For that Mitsu, a few degrees would be all that's needed to help it deliver just a little more power than on the other oils.

ARCOgraphite · Apr 18, 2012

I love high dyno numbers and a rod through the block

mechtech2 · Apr 18, 2012

Nascar cars use 5W for qualifying.

So yes, power should be up with thinner oils.
Is it worth it ? what about long life?

SteveSRT8 · Apr 18, 2012

The number one ford builder in the country uses 10W for dyno runs.

If you set the engine clearances then you know. If you don't it could be an expensive mistake.

My 1998 Neon R/T had very small gains from oil, it can be noticeable on a smaller engine.

bluesubie · Apr 18, 2012

Originally Posted By: ARCOgraphite
I love high dyno numbers and a rod through the block

WRX owner's that have had a bearing failure on the dyno right after an oil change would agree.

-Dennis

bogan · Apr 19, 2012

Thanks for your reply's guys,

I agree with Jim Allen that the video may have been rigged.
I also agree that I may need the thicker oil to protect my engine on the dyno.
I am just trying to get every last bit of HP out of it (for bragging rights)and thought that the thinner oil may produce a few extra HP.

PZR2874 · Apr 19, 2012

I noticed a difference running 5-30 (Pennzoil Platinum or Pennzoil Ultra) as opposed to 5-40 (T6) in my speed when I first bought.

I was thinking the 5-40 would be some extra protection and since I had a bunch on hand (from my Subies) I would try it out on the Speed.

Low and behold, the 5-40 bogged the little 2.3 down to where I could actually feel the difference.

2 days later I drained it and have been using 5-30 Pennzoil Platinum / Pennzoil Ultra ever since and it made a HUGE difference.

Just wanted to share.

bogan · Apr 19, 2012

Originally Posted By: PZR2874
I noticed a difference running 5-30 (Pennzoil Platinum or Pennzoil Ultra) as opposed to 5-40 (T6) in my speed when I first bought.

I was thinking the 5-40 would be some extra protection and since I had a bunch on hand (from my Subies) I would try it out on the Speed.

Low and behold, the 5-40 bogged the little 2.3 down to where I could actually feel the difference.

2 days later I drained it and have been using 5-30 Pennzoil Platinum / Pennzoil Ultra ever since and it made a HUGE difference.

Just wanted to share.

Thanks, That's interesting.

Saab recommends 40 weight or 30 weight.
Everybody I speak to on Saab forums runs rotella 5w40.
But also some do use 30 weight, but our oil pumps have a hard time grabbing 30weight at idle.And some have reported oil lights.

I was pretty much just going to do the dyno run with the 30weight, then switch back to the 40weight

PZR2874 · Apr 19, 2012

5-30 even for a short time on the Dyno will cause blow-by

You have an OCC/AOS on there already?

A_Harman · Apr 19, 2012

Do the dyno runs with the same oil that you normally run on the street or track. There's no use screwing around trying to maximize a dyno reading to squeeze out another 2 HP. You shouldn't let a big reading on the Egojet affect your sense of self-worth. If somebody that I pass during a track day asks me how much power my car has, I look at his car and subtract 50 HP before answering. "Yeah, the old girl needs a rebuild, she's getting pretty tired."

Vikas · Apr 19, 2012

Has anybody ever ran a dyno back to back? What was the variation in the results?

This forum would be so different if basic understanding of Statistics was made a requirement before becoming a member.

- Vikas

A_Harman · Apr 19, 2012

I've done back to back runs with my Camaro on a Mustang dyno. The readings ranged between 300 and 320 depending on how much time we allowed between runs to allow the engine to cool. With a cool engine, it would do 320.

PZR2874 · Apr 19, 2012

Originally Posted By: Vikas
This forum would be so different if basic understanding of Statistics was made a requirement before becoming a member.

- Vikas

What's this supposed to mean?

Solarent · Apr 19, 2012

Originally Posted By: Vikas

This forum would be so different if basic understanding of Statistics was made a requirement before becoming a member.

- Vikas

so true... so true

KrisZ · Apr 19, 2012

Originally Posted By: Solarent
Originally Posted By: Vikas

This forum would be so different if basic understanding of Statistics was made a requirement before becoming a member.

- Vikas

so true... so true

For "bragging rights" you don't need to cloud your head with such details.

PZR2874 · Apr 19, 2012

Tell me this Oh Big Bad Dyno Guru's...

What helps keep engine temps down more? 5-30 or 5-40

SteveSRT8 · Apr 19, 2012

Old news, lighter oils run lower temps, if all else is equal.

Jeff_in_VABch · Apr 19, 2012

Originally Posted By: Vikas
Has anybody ever ran a dyno back to back? What was the variation in the results?

This forum would be so different if basic understanding of Statistics was made a requirement before becoming a member.

- Vikas

All chassis dyno shops will provide at least 2 to 3 runs. Of course most people will only use the highest numbers.

On a chassis dyno, the variation are huge. Expect 10% variations per run. Then people get really crazy and try to estimate crankshaft HP since their wheel HP seems low. Of course, thats impossible. A chassis dyno is really just a qualitative tool, not a device for determining accurate HP numbers. Changes in tire temp, pressure, size, gearing, etc. all majorly affect the numbers.

A vehicle can be tuned on the chassis dyno using EGT and O2. But it is not accurate enough to determine if bolt on modifications increase or decrease power.

It is still a lot of fun and gives you an idea of your power level before bolting on that blower.

Vikas · Apr 19, 2012

A course in statistics would convince you to look at the data with a critical eye. A 2 hp claimed increase when the standard measurement error is of an order of magnitude higher is just a noise.

This principle holds true for all the quantitative data which is being paraded around. This is particularly annoying when people talk about 0.5mpg increase with the use of their favorite snake oil.

- Vikas

oil weight = HP

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