The Lotus Cars Community banner

1 - 18 of 18 Posts

·
Registered
Joined
·
400 Posts
Discussion Starter #1
I figured I'd start a thread to document a project that has been a slow burner up to this point. I've always wanted to increase the power output of my Elise, which is primarily used for track days. The loose goal is to build something legal for use in SCCA TimeTrails, Global Time Attack and the new SCCA XSB auto-x class. So... powertrain is mostly open, drivetrain swaps are fine, ECUs are open... etc.

I found a used RevX kit that I thought would be a good base for my build. The main elements I wanted from the kit were the BOE intake manifold, whipple supercharger, supercharger inlet adapter (actually adapters, plural, with the RevX kit) and some of the plumbing associated with the supercharger heat exchanger system. The kit was way more rough than the pictures indicated. Everything was in need of reworking.



















I couldn't handle the 3D printed Rev400 to Whipple supercharger adapter, so I designed an aluminum version.



Fitment was reasonable when it came in, but needed port matching with the Rev400 inlet adapter and supercharger housing.







Thanks to a tip from Fred Zust, I picked up a 2007+ Tundra DBW throttle (76mm plate) to replace the stock DBW throttle. It's plug-n-play with the Elige engine harness and my Haltech ECU was able to operate it without recalibration... though it did produce DTCs for high throttle current draw. After recalibration, everything worked fine.


In order to install it with the Rev400 inlet adapter, another adapter (yes, that will be 3 adapters in series) was needed to clock the hole pattern relative to the stock TB.





The Rev400 inlet measured at 72mm and needed to be port matched to the Tundra TB adapter plate.






There's a lot let to finish up before the supercharger is ready to go into the car...

  • E153 build with Kaaz gears and Quaife LSD
  • Design and fab 10-rib serpentine pulleys (any other RevX owners want to split manufacturing a batch?)
  • Pin the crankshaft and crank pulley
  • Install low-compression pistons
  • Install high-strength rods
  • Rebuild cylinder head with VVL killer rockers & associated hardware
  • Build new Haltech Elite1500 adapter harness with more appropriate sensor suite
  • Exhaust work...
  • Fuel system work...
I'll try to keep this thread updated with more pictures along the way.
 

·
Acme Super Moderator ** The Enforcer **
Joined
·
7,053 Posts
I'm jealous. Perhaps when I have a lot of money laying around not being used, I'll do something similar. Thanks for posting.

San
 

·
Premium Member
Joined
·
1,388 Posts
Nice work. Looking forward to reading the next update.
 

·
Registered
Joined
·
400 Posts
Discussion Starter #7
Kaaz gear set came in.

Kaaz gear set box... lots of parts


Input shaft - dark spots are just corrosion inhibitor collected in areas


They appear to have the same synchro design as the E53 I bought to harvest gears 3,4,5 for an E153 build

Kaaz synchro design - this looks like 5th gear on the input shaft


Gear set (synchro design from E154F gear set) that came with the first E153 Frankenstein I bought... 3rd gear synchro specifically


Gear set from E53 (3rd gear synchro pictured)
 

·
Vendor
Joined
·
3,137 Posts
Cool Project! I've had some thoughts on doing a 10 Rib Custom ATI Damper Pulley. Might be a good project especially if there are other folks interested.
 

·
Registered
Joined
·
400 Posts
Discussion Starter #9 (Edited)
Well... my project is stalled waiting on parts/pieces to arrive during this... umm... interesting period. So, I'm tinkering with various small projects I've had in mind.

One such project - compare my Haltech Wideband O2 sensor to my AEM X-Series inline Wideband sensor. I got the idea from Speed Academy, as they did a similar survey of AEM, Innovate, and PLX wideband systems.

Both sensors are plumbed into a Mk3 RaceCapture. The AEM is connected via an analog input. The Haltech WBO2 system only has a CAN interface. Both systems are being logged at 50Hz. Haltech doesn't provide much information about their CAN channels and modules, but the WBO2 system appears to broadcast at a ~20Hz rate. There are repeat readings when the signal is polled at 50Hz via the RaceCapture.

Here's a graphic of my logging setup:


AND... here are the results:


A few things become apparent after review. 1) It is easy to make out the more discretized nature of the Haltech CAN signal. 2) The response of the systems is different. The 2nd subplot paints the picture well. When the system is nearing steady state, the delta between the readings is relatively small. However, anytime there is a fueling transient, the Haltech signal lags.

This makes me want to figure out how to spoof the AEM X-series analog or CAN signal into the Haltech ECU, making it think it's the Haltech WBO2 module.
 

·
Registered
Joined
·
1,218 Posts
Cool Project! I've had some thoughts on doing a 10 Rib Custom ATI Damper Pulley. Might be a good project especially if there are other folks interested.
I actually contacted ATI about doing this. They said they could probably modify their existing 2ZZ pulley.
 

·
Registered
Joined
·
40 Posts
I actually contacted ATI about doing this. They said they could probably modify their existing 2ZZ pulley.
I'm not familiar with "Damper Pulley". What is it and what is the benefit?
The only clue I see is "Designed and tuned to eliminate harmful crankshaft harmonics that cause parasitic HP loss."
Which pulley gets replaced?
 

·
Registered
Joined
·
400 Posts
Discussion Starter #13
A damper pulley, aka harmonic balancer, is a tuned mass damper (TMD). The goal of a tuned mass damper is to reduce amplification of a structure at resonance. A crankshaft has torsional resonances, which are excited by the oscillatory torque inputs from the individual cylinders firing. Each torsional resonant frequency of a crankshaft aligns with a specific engine speed. If the resonance aligns with an engine speed that is common to highway driving, say ~4000 rpm while driving on an interstate, the crankshaft will experience millions of cycles of torsional resonance. This can lead to premature crankshaft material fatigue and potentially failure of the crankshaft due to the amplification that occurs at structural resonance.

A TMD can be designed to affect a specific modal frequency and mode shape, dramatically reducing the amplification that occurs at resonance . In the case of an crankshaft, this would allow an engine to sit at the engine speed that would align with the critical resonant frequency without incurring significant accelerated damage. The harmonic balancer mounted to the snout of a crankshaft does exactly this. It is a ring of material (usually steel) coupled to the crankshaft via a ring of rubber. The ring mass and stiffness + damping of the rubber is tuned to match a critical torsional resonance of the crankshaft.

For a car that doesn't sit at critical engine speeds for long periods of time, I would guess a harmonic balancer is unnecessary. I would also venture to guess that OE harmonic balancers are designed to attack frequencies and RPMs that are common for highway driving... not the high engine speeds more common to tracking.
 

·
Registered
Joined
·
204 Posts
So Jake, would that mean that other than a loss of potential longevity, removing a harmonic balancer would shed rotational mass and thus gain faster RPM gain? And potentially hp too?
 

·
Registered
Joined
·
400 Posts
Discussion Starter #16
So Jake, would that mean that other than a loss of potential longevity, removing a harmonic balancer would shed rotational mass and thus gain faster RPM gain? And potentially hp too?
Effectively, yes. Rotating mass requires torque to accelerate that mass. Mass at a large radius from the rotation axis requires significantly more torque to accelerate it than that same mass located closer to the rotation axis. Any effective gain in torque is a direct increase in HP... as HP is effectively just torque at a given speed.

The moment of inertia equations effectively boil down to I (inertia) = mass * radius^2. Torque required to accelerate the inertia = I * a (alpha, or rotational acceleration of the object).

If we assume the balancer mass is a ring of steel, 7.5" OD, 6" ID, 1" wide, it has an inertia of .015 kg*m^2 (yep, I'm switching to SI units). Now, if we assume the vehicle accelerates to redline in 1st gear in 3 seconds, our alpha = 8500rpm / 3s = 2833 rpm/s... or 297 radians/s/s. Torque required to accelerate our steel ring = 0.015kg*m^2 * 297rad/s/s = 4.5Nm or 3.3ft-lbs. In 2nd gear, this drops to 2.1ft-lbs... and so on for each gear increase.

But, you can't just remove the harmonic balancer. It doubles as the serpentine drive pulley. So, you would need to replace it with a solid aluminum or other pulley of equal diameter in order to maintain accessory drive ratios. Those pulleys will have inertia, too, so you can't gain all of that torque back.

So, when someone makes a claim like a pound of rotating mass is worth 10 pounds of non rotating mass, you can reply by asking, "where is the mass and what is the rotational acceleration?"
 

·
Registered
Joined
·
656 Posts
posts like this, with math, engineering and racing are what make lotustalk great, thanks for sharing your thoughts.

about the oxygen sensor comparison... do both units use the same sensor probe? (i.e Bosch LSU 4.x/5.x?)?
 

·
Registered
Joined
·
400 Posts
Discussion Starter #18
Same sensor, LSU4.9 in both cases.

What I have realized since posting the plots, is the Elite1500 is generating the "AFR" CAN message and I'm not logging the actual message from the Haltech WBO2 controller. Haltech doesn't post all of their CAN IDs, so I don't know what the message ID or data structure is for the module. I've asked them for this info and I have ordered a CAN bus analyzer to better investigate what messages are broadcast on the bus.
 
1 - 18 of 18 Posts
Top