Looking at realistic hp numbers
 

Looking toward future car and have been lurking as well as received several PM's from members who took the time to answer. My question or questions:
Looking to find out how much power is lost between crank and at the wheels. When I had my last Mustang, it cranked at 412 but around 370 at the wheels. However, several folks here have said that with older power that I would lose a higher percentage from crank to wheels. I would like 300 at the wheels without losing the ability to use it on the street or having to tinker with it every day or two. I was looking at Ford power but it seems that getting 300+ at the wheels might be a stretch without forced induction or spending more that I would have in GM power.

From what I have found, 20% loss between crank and wheels seems to be about what to expect. Maybe more, maybe less given an auto or manual. New cars appear to lose less then older builds. Case in point my newer Mustang which lost around 10%. Interestingly, is apprears that a belt driven fan may be one of the biggest culprits in robbing hp. Seems like a clutch driven or best an electric would be the way to go. Still learning...

For what it's worth my Camaro coasted much farther than my Miata will. In the Camaro coming into town from 65 I could slip it into N at the last gravel before the speed dropped to 30 and it was perfect. So it took 1 mile of coasting to drop from 65 to 30. Same engine and trans in the Miata and the Miata is stopped before I get to the speed limit change.

I wonder if the CV joints turning in the rear instead of the solid axles makes a little bit of a difference. The windshield on the Camaro was much steeper so I would imagine the areo was a little better on it than the Miata. Also the Camaro got the same or maybe slightly better mileage and you would think shedding 1200 lbs would have improved mileage in the Miata.

It probably means nothing to the question but just a weird thing.

Trying to figure parasitic losses difficult
 

Trying to figure parasitic losses are really hard. There is no doubt in my feeble mind that new cars do indeed give away far less in losses then older cars even those like your camaro which weigh more. I am sure it is many things that add up to more HP loss then we would like. I started thinking about it when my 2012 Mustang and others like it, only gave up about 10% between crank and wheel HP compared to sometimes three times that much with the Miata and older engines. Given our search for more HP, it would seem that if we could capture some of those losses that we could gain 50+ HP easily...There must be someone out that with some of the answers but so far, I have not found the exact reasons....

The 98-02 Camaro was actually very sound in the aerodynamics department. I think momentum also had a bit to do with it rolling further. I also noticed the Miata drops speed rather quickly when you get out of the throttle, almost like a truck.

Hey that is good to hear Mike. Well not good but at least I know feeling like I have a parachute is normal now! When I first noticed it I looked for brakes dragging but everything seemed fine. I know from my pinewood derby days that weight is a key factor in the coast distance so I expected the Maita to not do as well but I did not expect so much difference.

I really did expect a few more MPG out of the little guy but I have yet to be able to keep my foot out of it and really test it for MPG so I may never know. That might be something for you the know Chuck. I have no idea why but this Miata just ends up getting driven harder than any of the 6 Camaros and Mustangs I have owned. It is every bit as thrilling as it was to slip behind the wheel of that 65 fastback when I was 17. Truth to be told the Miata is the first car I have ever thought was better than that first Mustang...
Attachment 7594
Not the wife though. No need to trade perfection!

Jim,
Glad to know that you are a former Mustang owner. I owned a '66 back in '67. Always wanted another but my next one did not come till 2012 with the 5.0. Then my "wants" went to something like the Miata with V8 power so here I am. The parasitic losses really between new and old really got me to thinking and I posted another post strickly about parasitic losses. Hopefully, someone can come up with reasons why and ways to cut that loss down. I would rather get 50 HP from cutting down parasitic losses then from putting a lot more $$ in the engine...

Parasitic losses come from a lot of places, and there's a lot you can do to mitigate that without spending big bux. New cars have few losses and get good gas mileage because the engineers have been working on these things for years.

Pay very carefull attention to friction. Mechanical parts moving around will always cause some friction. Use quality lubricants, like a pure synthetic motor oil, trans lube, and diff lube.

Don't use oils that are heavier than you need. 5W-30 true synthetic motor oil has less resistance to movement than 15W-50 Dino oil. (BTW, there are only 4 true synthetic motor oils on the market, and M1 is not one of them.)

The CV joints in an IRS are less efficient than a solid axle.

Do you really need a big 140A alternator? If the draw is only 40A, that's what the alternator will make. It only makes what is is needed. If you have a bigger/heavier alternator than you need, it will take more power to spin it.

Same thing with the drive shaft. Do you really need a 3" steel shaft? Also, an incresed pinion angle will increase frictional losses.

Some tires have more rolling resistance than others. As do underinflated tires.

Other than thos simple things, you'll spend a lot of money doing engineering changes for minimal return.

Hey Bob welcome abord! So what do you like for oil? I'm running Moble 1 5-30 in the engine, Synchromesh in the trans and Valvoline synthetic 75-90 in the diff and thought that was as good as it gets.

I'm not following why a 3" steel shaft is not good but yeah big soft tires roll like a turd for sure.

boB,
Good points. I agree about the lubricants and know that M1 is not a true syn.
Always have used a top tier syn for everything I can. The alt and drive shaft issue make sense. I guess that we do what we can and then build the engine to get what power we want.

Careful Jim. Favorite oils can start wars...

Wow didn't know that. So what do ya run then?

Jim,
I run Amsoil in most everything. Their signature series 5-30 in sump and their severe gear in the diff but not sure for the next Miata and will depend on the engine and rear end. I know that in the lab that one syn may have less resistance then another however, (and here is comes) I don't think it makes much difference in the cars discussed here. I would imagine that M1 would not show any more noticable parasitic loss then the best syn made in a built Miata.. I think using a good syn and making sure you keep the oil clean is the name of the game.

Too true! Yeah I doubt the difference would be measureable but fun to hear what guys run. I used to run Amzoil back in the day but too hard to find anymore. Not stuck on M1 for sure but I do really like the Synchromesh over ATF in the trans.

A 3" steel drive shaft is heavy, and takes energy to spin. Light weight alum or even carbon fiber will free up a small amount of HP.

As for oil...... Don't want to start a war or an argument. ;)

A true synthetic motor oil starts with a PAO base stock, and then additives are used to acheive the desired results. The big advantage to a synthetic is it's ability to stand up to heat better - high rpm's, turbo's, etc.

They are also a little bit "slippery-er", and cause less parasitic loss. Not very much, though. It's not like you'll see a 10% increase.

There are only 4 oils that I know of that start with a PAO base stock. Royal Purple, Redline, Amsoil, and another one I can never remember the name of.

I use a Royal Purple in my race car, because of the RPM's. It's reasonably priced and easy to come by. But all my other cars get dino oil.

The Harley also gets RP, because it is air cooled. UOA shows that M1 can't stand up to the Harley, but RP can.

M1 is not a bad oil. In most cars and trucks it seems to do just fine. It's not true synthetic, but it's priced like one. IMO, that makes it a bad value. But for most cars with a reasonable change interval, it will perform just fine.

Thanks Bob! Any relation to Bob the oil guy...?

For all it worth. My 99 miata with a GTO LS1 with a t5 racing trans, alum drive shaft, CTS rear end with custom transaxles. 330 RWHP 384 torque. All the best fluids as well. The Motor has a vac. pump as well

No relation. But I have read through that site extensivly. Lots of really good science there.


What year is your engine? Did you change anything from stock- Cam, tune, etc?

Obviously, I'v got a miata/V8 project in mind. I'm here to find more info about that.

Did not change a thing. Gm performance crate motor (01), I think, long block with a LS6 intake. and of course the vac pump. also added two pressure equalization lines from the front of the valve cover to the front sides of the oil pan. I have had engine oiling issues while racing and that did the trick. I can help a bunch

All the track rat turbo Miata guys swear by Rotella T6. I ran it in the 1.6 and the 5.3 with good results. Its one of the few oils that made the 1.6 quick lifter ticking.

Cut the back bumper up higher. It acts as a parachute.

With the price of a new Speedway aluminum 3" shaft, I don't understand why anyone would go elsewhere. Its balanced and comes with the new joints and slip yoke.

Interesting I never thought about Rotella before. If the hype is true that might be the way to go. Cheaper than Mobile 1 too.

Good point on the rear bumper cover. Thanks Mike!!

Shell Rotella is diesel dino oil. Not a bad oil, but it's designed specifically for diesels. Mostly with added detergents to pick up the extra soot and keep it suspended. I don't suppose there's anything wrong with that for a gas engine, but I don't see that as an advantage, either. Probably just as good (and maybe slightly better) than standard gas dino oils.

Shell Rotella also comes in a "synthetic" version. It's also a dino oil like M1.

The diesel oils used to have significantly more Zinc than gas oils. Zinc is the anti-wear additive that was removed from gas oils to protect the cats. But the newer diesel engines also have carts, so the CJ diesel oils have significantly reduced their zinc content as well.

If you want the added zinc, you need to use a racing specific oil, like Bradd Penn. Or add it to your favorite oil. I add Comp Cams break in additive at every oil change.

Many of the companies are adding zinc back to some of their oils to bring the "Hot Rod" guys back into the fold. I think even Amsoil has added a new oil for that purpose but can't say for certain. Learning about oils will hurt your brain but there is some great info at bobistheoilguy and you certainly learn what seems to be hype and what is truth. And believe me, there is a bunch of hype out there about oils...If you say it enough, most people believe it.....

You are one handy guy to have around Bob!! Just for us that are a bit new to all this what does the term dino mean? Or maybe better stated what is dino oil verses other types of oil?

Dino oil comes from dead dinosaurs (maybe). Petroleum based, rather than PAO. Not a true synthetic.

The current crop of "synthetic" oils is a trick of marketing. What they call synthetic now is dino oil that's been refined enough to meet certain performance charectoristics. That's good for the oil company, because these dino synthetics are cheaper to produce. They still charge high prices, and their profit margin is bigger.

Finding this information is very difficult. But it appears that the only Mobile 1 that is still a PAO base stock is their 20W-50 motorcycle oil.

Jim,
Oil is complicated and as boB said, a large business designed to sell oil. It takes time to find what is in each oil and choosing the oil that BEST serves YOUR purpose. Oils are designed to different standards for a reason. You have look hard to find the info that you want but it is out there. boB is correct in dino oils(from compressed peat, dinosaurs etc.) not being PAO based and that few companies use the PAO base stocks. Do you need a PAO based syn? That is the question we all have to answer for ourselves. I do, but then I am a tad OCD..

Wow I never realized they lie to us! I just want it to survive a track day now and then with out spending 80 bucks to change oil!

Given what you use, you should be fine. I would watch oil temp and as long as it is not overheating then you should be fine. Many things we do are overkill and trackers have used dino oil for years with no damage to their engines. The V-8's used in most Miatas are not reved to 8,000+ in every gear and engine tolerances are not as refined as many hi tech engines. I would imagine that M1 will work fine for you as long as you keep it clean. Again, this is just my opinion and I am just getting into the V8 Miata. I have looked at oils for several years and know older V8's but I am not an expert..

I don't see many V8 Miatas running "regular" street tires. I see big, sticky tires which are not easily pushed around. Also, the Camaro weights a 1,000 lbs. more than a Miata (mine weighs 2660). The Camaro has a lot more inertia at 65 mph to carry it further down the road.

Jon,
I agree. I think it is everything working together. Big tires, belt driven pulleys and fans as well as unsprung mass that we do not think about.

Even with the back seat removed and what not the Camaro was a pig at 3715lbs. The Miata is 2580 so no question the mass makes a big difference in the coast.

The Camaro had 295/30- 18s on 11 inch wide wheels and the Miata has 225/45-15s on 9. So pretty much apples to apples tires for the size to each beast but I sure wish I could run 250+ wide on the Miata!

I'm thinking about doing another cam swap on it this winter and if I do will probably do a dyno to tune it next spring and find what the rwhp is .

I run 245/40/15 on my road race miata. Tons of grip. I need a better seat! I'll tell you for the money, I was .550 slower than a full race viper at Thunderhill at the last race and the car has more to give. All that for 35k

Wow, this started out as a HP thread then Mustangs, then oil then tires. Well I can chime on on all of these. My 1st new car was a 66 Sprint 200 Mustang. Then replaced that with a 66 271HP Pony Package Mustang convertible, replaced that with a new 70 Mach 1, 351 Cleveland engine with ram air/shaker hood in Grabber Blue. Been a Ford guy ever since. Then a few years ago got a 66 Sprint 200 convertible for my wife--that car's been sold. Now, Miata's. Bought my wife a year old 93(auto) Miata. Loved that car, reminded me of my old Triumphs--except maybe a 1000% more reliable. Then I got the road racing bug and got myself a 91 R package Miata, then very stupidly replaced that with a 93 JR(M45)SC Miata. Then a few years ago found a V8 Miata on E-Bay that did not sell, a Ca. rust-free track car. Had it shipped to NJ. The 302 engine lasted 2 or 3 easy track laps before it blew. Got in touch with Jason (MRM)-explained to him I am no mechanic--just a driver. Wanted him & his dad to build me the most solid reliable NA track engine they could. They did--actually twice. A 302 stroked to 331. Had the car dynoed by Tom(Jason's dad) a couple of month ago--306hp. He said with some tweaking he thought he could get another 25-50hp out of it. With my track season ending last week--that is the plan for this winter.

Oils: Initially Tom recommended a Valvoline 20-50 conventional racing oil with a Valvoline engine break-in additive.
Then the guy that maintains my track car had me switch over to M1 10-30 full synthetic. Been running that the past few years. Seems to work for me.

Tires:
Car came with 255-50-16's rear and 245-40-15's up front. Those were were fairly old and rock hard rubber. Replaced those with Toyo RA1's. 205-50-15 up front and 225-40-15 in rear. Then switched over to Toyo 888's, had front fenders cut and flared, to fit 235-50-15's all around. My 888's were down to the cords but I did not want to get new tires for my last few days on track so managed to stay on the track more or less with these 888's. But a friend at the track had a set of somewhat used but at least not corded--Hoosier racing slicks mounted on the same Kosei K1 wheels I use sitting in his trailer. These are 23.5 X 9 X 15, these were a huge improvement over the corded 888's. The difference was like going from my 1.6 to the V8. I've already ordered a set of these Hoosiers for next year. Although I don't drive this car on the street. The little I did, I found the 888's and RA1's a really good fit for track and street use on my V8. Obviously, now with these slicks--they will see even less street time then the little I did before.

So, I think I about covered all the bases here.
Mustangs
Miata's
oil
Tires

M,
Good info. This thread has taken on a life of its' own but that is fine as there is a lot of good info given. Being new to the V8 Miata, all of this helps in my search for what exactly I want or as close to it as possible. Was just trying to see how much rwhp I could expect from a naturally aspirated SBF without buying a brand new crate motor...Want a dependable street driver that could play on a track or Xcross once in a great while..

Old Chuck
This thread has certainly wandered around a bit. Getting back to your original query: I think most of the guys with V8's use them for same purpose as you're wanting to. And the guys I know with V8's are really happy with them as street cars with some occasional track use. I am one of the few that has the car as a dedicated track car. I sometimes regret not being able to legally and comfortably take it out for a cruise every now & then. Even though it's registered, plated and insured it's not really street legal. Won't pass state emissions, no headlights or horn and calls attention to itself with big numbers and decals on the car. But, I do sometimes drive it to car shows or take it out for testing very early on Sun. mornings.
But getting back to your goals, I don't believe you should have any problem reaching your goal of a NA SBF with 300rwhp street car.

M,
Thanks. I thought the 300 was very doable but wanted to check in case what I have been reading elsewhere was just boasting. When you read about gobs of HP being produced, you don't always know how much money they threw at it or if it could idle on the street for very long.

Old Chuck
Regarding idling on the street-I can't do that without running hot. On the track no matter how hot the ambient temp is I barely touch 200 degrees. I have an oversized racing radiator and I have the original Miata fans mounted in front of the radiator wired together pushing air. Currently I turn them on manually but they are not very effective while idling on 80+ degree days.The off season plan is to wire them up to turn on automatically and possibly replace them with a more efficient set up.
When I am sitting in the grid before going on track I always keep a close watch on the temp gauge. I often just shut the car down while in the grid. If I took the car out for a drive and got stuck in stop & go traffic, especially on a hot day, I'd have a big problem.
This gives me an idea to post a question on here about cooling. You should contact Jason(MRM). He used to have cooling issues. I know he went to a waterless system and I think he's happy with it. I don't know what else he's done.

It's interesting that that's where your at Morris. I'm at the point now where I have no on street over heating issues, even with the AC on full blast. Evans Waterless Coolant, placing the fans behind the radiator with an effective shroud and installing hood vents in a scientifically proven location took care of that issue. I run between 200 and 215 on the street now. On the track I still start to creep up toward 240 if I'm pushing it. It does not seem to go past that point though. I was seeing it hit 250 and keep going but just adding five rubber Spal pressure-relef flaps to the shroud brought it down to where I am now. I have the radiator ducted on the top and bottom but not on the sides. I'm pretty sure that extra effort could bring my on-track temp down even further.

Pullers or pushers that were meant to be pushers (the Miata fans you have were not) would make a difference for you.

-Jason

Jason,
I'm kind-a surprised that you're running hotter on the track then on the street. On the track I mentioned nearing 200 degrees--I meant 210. I don't know where my boiling point is & I don't want to find out. When I'm sitting in the grid and I see the temps approaching 220 I shut it down and run the fans. As you know I have no ducting anywhere, I don't know if the front splitter has any effect or not. But, since it's a track car & temps continue to run in the normal temp range it's not a real priority but something I would like to address this winter. One other thing I need to look at is better oil pressure management. Toward the end of the season we made some adjustments to suspension and I've gotten pretty comfortable with the car now, so my cornering speeds have increased dramatically. To the point now (the GT3's can't shake me anymore)that my oil pressure in the corners is dropping from 50psi to 20-25psi. I'm open to suggestions.