Lotus v's Aftermarket Supercharging

[TheViper]

If Lotus HP and torque numbers are at the flywheel and BWR and Katana, all using similar superchargers are at the wheels, why the difference, what am I missing?

Elise 2008 SC 217 hp, 156 ft/lb torque at flywheel -
15% drivetrain loss = 184 hp, 132 ft/lb torque at wheels

BWR supercharged 223 hp, 146 ft/lb torque at wheels -
15% drivetrain gain = 262 hp, 172 ft/lb torque at flywheel

Katana supercharged 216 hp, 142 ft/lb torque at wheels -
15% drivetrain gain = 254 hp, 167 ft/lb torque at flywheel

[akandok]

Possibly boost pressure. Tuning. Efficiency of the supercharger.

The most gains I have seen on cars are from Prochargers. I wonder how come no one went that route yet..

[Bane]

Intake manifolds are different across all three of them as well.

From what i understand, Lotus is using the Toyota supplied one, Sector 111 is using the Greddy/Trust one, and Blackwatch has created their own that's been optimized for the Elise (hence the slightly higher power rating).

The all have slightly different fuel injection setups as well. Lotus = stock, Sector = CharlieX ECU + stock injectors(?), Blackwatch = PES ECU + aftermarket injectors

[richw350]

Isn't the 2008 SC different as well?

As I understand it:

2008 Elise SC = M45 SC
Katana & BWR = M62 SC

[mp3moose]

Warranty. Lotus design has to be more conservative.

[darkSol]

That doesn't explain why 2007 Exige S's typically dyno between 200 and 208 whp.

My N/A Elise dynoed at 167.31 whp bone stock, which is more like a 12% loss. 190 - 12% loss = 167.20.

That would mean the 2007 Exige S's are making 227-236 hp instead of the advertised 220hp.

Try and recalculate your numbers with a 12% loss instead of the 15% loss - I think it'll be a bit more accurate.

[TheViper]

Originally Posted by darkSol

That doesn't explain why 2007 Exige S's typically dyno between 200 and 208 whp.

My N/A Elise dynoed at 167.31 whp bone stock, which is more like a 12% loss. 190 - 12% loss = 167.20.

That would mean the 2007 Exige S's are making 227-236 hp instead of the advertised 220hp.

Try and recalculate your numbers with a 12% loss instead of the 15% loss - I think it'll be a bit more accurate.

OK here's 12%:

Elise 2008 SC 217 hp, 156 ft/lb torque at flywheel -
12% drivetrain loss = 191 hp, 137 ft/lb torque at wheels

BWR supercharged 223 hp, 146 ft/lb torque at wheels -
12% drivetrain gain = 253 hp, 166 ft/lb torque at flywheel

Katana supercharged 216 hp, 142 ft/lb torque at wheels -
12% drivetrain gain = 245 hp, 161 ft/lb torque at flywheel

[MotorCade]

Originally Posted by Bane

Intake manifolds are different across all three of them as well.

From what i understand, Lotus is using the Toyota supplied one, Sector 111 is using the Greddy/Trust one, and Blackwatch has created their own that's been optimized for the Elise (hence the slightly higher power rating).

The all have slightly different fuel injection setups as well. Lotus = stock, Sector = CharlieX ECU + stock injectors(?), Blackwatch = PES ECU + aftermarket injectors

Actually, we're (Sector111) using RC Injectors. The company has years of experience with high revving/small displacement motors, and makes a great injector for our application. In addition, the tune is completely contained within the stock ECU housing, no piggybacks.

Cade

[GTsRasta]

The differences in power is to minimize wear and tear on our motors that came NA stock, just so it could last longer.

Originally Posted by akandok

Possibly boost pressure. Tuning. Efficiency of the supercharger.

The most gains I have seen on cars are from Prochargers. I wonder how come no one went that route yet..

That kumo-tec guy is running a centrifugal supercharger, and a 2zz swapped MR2-Spyder owner over at spyderchat.com has a 313 whp rotrex centrifugal supercharged setup on stock internals.

[Z-dculus]

Originally Posted by GTsRasta

The differences in power is to minimize wear and tear on our motors that came NA stock, just so it could last longer.



That kumo-tec guy is running a centrifugal supercharger, and a 2zz swapped MR2-Spyder owner over at spyderchat.com has a 313 whp rotrex centrifugal supercharged setup on stock internals.

could that same setup fit in the elise engine bay?

[GTsRasta]

It fit under the MR2-Spyder lid with some moving around, but I really don't know about the Elise. They're basically custom jobs. I believe the owner of the car, grumpy, is signed up here if you want to ask him directly. The details of his 2zz swapped build start here in this thread after the custom builder did his own 1zz build, at post #407. It really is epic:

http://spyderchat.com/forums/index.p...post&p=4479648

Also check out that kumo-tec guy's posts for his centrifugal supercharger setup in his Lotus. But it really is a costly route, especially since the centrifugal supercharger units themselves cost an arm and a leg. I'd just get an aftermarket supercharger kit with an intercooler and call it a day. I'm personally scrambeling to see if a A2W unit will get made for my car. You guys are lucky to have kits coming out with them.

[MikeW]

Originally Posted by darkSol

That doesn't explain why 2007 Exige S's typically dyno between 200 and 208 whp.

My N/A Elise dynoed at 167.31 whp bone stock, which is more like a 12% loss. 190 - 12% loss = 167.20.

That would mean the 2007 Exige S's are making 227-236 hp instead of the advertised 220hp.

Try and recalculate your numbers with a 12% loss instead of the 15% loss - I think it'll be a bit more accurate.

I alway thought the 15% figure was something grabbed out of the air without any any testing. If 15% was correct, my N/A with header (1777 whp) would be putting out 208 at the crank. I think 13% is closer. Of course that's a guess, just like the 15% everybody thinks is correct.

[Murix]

We do not have enough data to answer this question yet. At least that I am aware of.

[GTsRasta]

13-15% drivetrain loss is the acceptable range. I usually like to do 14% since it's in the middle.

[fzust]

Originally Posted by Bane

Intake manifolds are different across all three of them as well.

From what i understand, Lotus is using the Toyota supplied one, Sector 111 is using the Greddy/Trust one, and Blackwatch has created their own that's been optimized for the Elise (hence the slightly higher power rating).

The all have slightly different fuel injection setups as well. Lotus = stock, Sector = CharlieX ECU + stock injectors(?), Blackwatch = PES ECU + aftermarket injectors

Blackwatch is using Bosch injectors + tuned Lotus ECU by PES who has 10+ years tuning experience (no piggy backs). We custom CAD designed the manifold to open up the 4th runner for better flow matching.

That said, be careful comparing different cars and different dynos under different conditions there are alot of variables to account for.

[Westrock]

Originally Posted by TheViper

OK here's 12%:

Elise 2008 SC 217 hp, 156 ft/lb torque at flywheel -
12% drivetrain loss = 191 hp, 137 ft/lb torque at wheels

BWR supercharged 223 hp, 146 ft/lb torque at wheels -
12% drivetrain gain = 253 hp, 166 ft/lb torque at flywheel

Katana supercharged 216 hp, 142 ft/lb torque at wheels -
12% drivetrain gain = 245 hp, 161 ft/lb torque at flywheel

Where did a 2008 dyno at 191HP? I haven't see a "S" dyno less then 200HP.

[turbophil]

Now that everyone has their promotional plug in......

Let's look at what we know:

-BWR and S111 have nearly identical intakes (FYI, they're both CAD designed, ), where the Lotus Manifold is WAAAAAAY different (also CAD designed)...possibly, Lotus's integrated intake design is detrimental to hp?
-BWR runs a smaller pulley than S111, thus runs more boost, thus the most likely reason for more *peak* hp....assuming the dynos are all created equal...
-Sector runs RC injectors, while BWR runs Bosch...
-That said, the brand of after market injector on above two kits has as much to do with the HP variances as the price of tea in China does on how many Chipotle burritos I eat in a week Nothing.(RC, Bosch, they're both fine)

Now, what we don't know:

-What boost is Lotus running?
-What is boosted intake temp on the smaller 45 blower when compared to the bigger 62 of S111 and BWR?
-Is the 220 advertised HP "real"...I don't think anyone has any real whp dynos for this SC car...especially on a dynojet that others have recorded pulls on for comparison...
-How "safe" (read, room for improvement) is the Lotus tune when compared to BWR or Sector? For that matter, how "safe" is BWR? There's only a fraction as many track miles on that kit when compared to S111's... It's probably fine though, so forget it...

Ultimately, one cannot, absolutely not, compare the advertised figures of this new SC to what's available in the after market and possibly be serious. When it comes down to the brass tacks, it's all sorted in a drag race (mph, not ET), a dyno, and smoothness of power delivery....along with plenty of monitoring of course to make a judgement about sustainability.... Chances are that all the kits and OEM options are sustainable for now, with the aftermarket kits providing more HP/TQ than the OEM for obvious warranty and emission related reasons...

Finally, I'm not sure measuring parasitic drive-line loss in terms of a percentage is the best way to do it. I don't believe drive-line hp consumption has linear relationship to fwhp as a flat percentage would imply...

All the Best,

Phil

[darkSol]

x1000 to Phil's post above

[TheViper]

Originally Posted by Westrock

Where did a 2008 dyno at 191HP? I haven't see a "S" dyno less then 200HP.

This for an Elise SC rated at 217hp, flywheel, apply the 12% loss and there is the 191 whp. I don't believe one has actually been dyno'd, be interested to see though.

Phil, thanks for your concise explaination.

[Devious]

A few things to consider:

What does CAD have to do with performance - it is a simple drawing tool. It is just as posible to design a good part in CAD (or pencil and bar napkin for that matter) as it is to design a bad one... garbage in and all that. Even using some of the most advanced flow analysis software available, it is possible to not account for some variables that turn up in real world testing.

Addressing specific issues to flow, balance, velocity, volume, pulse tuning, etc. all help to produce an improved design, but even real world testing and tuning can only give results for a specific combination of variables. Start changing the exhaust, headers, etc. and the results change.

Drivetrain losses - Even if you can account for friction, thrust, deflection, windage, etc., you still need to account for differences in different dynos from the same manufacturer. Good luck.

Trying to compare results on different dynos is nearly impossible - especially when comparing rear wheel power. Even comparing results on the same car, same dyno, with different atmospheric conditions is not easy. The best weather station correction still does not account for something as simple as the correct ignition timing possible for best power on the same fuel as atmospheric conditions change.

And as for fuel, I have seen some pump fuels provide as much as 1.5% differences from the same octane, but different brand. Start testing fuels with different oxygenates or summer/winter formulations (MTBE, ethanol, etc.) and the variance can double.

Load: You can tune all you want on a dyno, but if the dyno does not load the engine the same as the engine is loaded in different gears on the road or track, the tuning is off, and power output is not optimal.

Lubricants: I have seen some engine/trans/dif lubricants alter output easily as much as 2%, and sometimes even more.



Just a few items to think about.