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159: BMW Direct Injection on MoTeC: Genius or Headache?

159: BMW Direct Injection on MoTeC: Genius or Headache?

Tuned In Apr 08, 2026 131 min
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About this episode

Greg Strom (Strom Motorsports) breaks down why modern direct-injection BMW tuning is far more complex than port injection—especially when using MoTeC standalone. He contrasts dyno “numbers” with real race-lap durability, then walks through DI fundamentals like injection timing, fuel pressure control, MBT ignition mapping, and the knock/mixture sensitivity that can swing power with tiny timing changes. Greg also shares his path from racing and coaching into motorsport engineering, plus real-world GT4/GT racing lessons on limp modes, traction/ABS behavior, and why factory ECUs can be frustrating. The episode ends with his current B48-focused parts/business direction.

Cars: BMW M3
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Technical Too Afraid to Ask
Company

High Performance Academy

"for those who are new to the TuneIn podcast, High Performance Academy is an online training school. We specialise in teaching people how to build performance engines, how to tune EFI, how to construct wiring harnesses."

High Performance Academy is a training site that teaches people how to build and tune performance engines. They also teach practical skills like wiring and using data logs.

Concept

track day

"...worked at a shop cleaning the floors to kind of learn what I could. Yeah I got to do my very first track day actually so this was I think it was like 1997 and I was 16..."

A track day is when regular drivers get time on a race track. You’re not usually racing other cars side-by-side—more like practicing and learning the track.

Car

e46 M3

"my dad picked up an e46 m3 with the smg like they had just come out with that and we started doing track days with that because it was a lot easier for me to drive because I couldn't shift"

The BMW E46 M3 is an older M3 generation. It’s a performance BMW that many people track, and the version mentioned uses an SMG transmission that can make driving easier for someone who can’t shift normally.

Concept

spec racing

"[614.9s] for racing for spec racing is the speccy 30"

Spec racing is a format where cars are kept close to identical (or tightly regulated) so competition depends more on driver skill and setup within the rules. The speaker later ties this to small power differences and shared suspension/brake rules making driver talent more important.

Term

slicks

"it's on 280 width slicks"

Slicks are race tires made for maximum grip. They work best on dry track days and help the car stick better when you accelerate and brake.

Company

MoTeC

"Interestingly though the MoTeC West Coast office at the time for USA they don't have it anymore but was was a couple... once I kind of got it going... I called up Shane Tecklenburg because he was he's the MoTeC guy... it’s 800 bucks for the day to come down and tune it"

MoTeC makes aftermarket computers for engine control. Tuners use it when they want more control than the factory ECU, especially for custom builds.

Term

ECU

"because most ECUs will have some kind of trigger scope or ref sync capture so you don't actually need to break out the oscilloscope... every calculation for fuel ignition is based on that information being valid."

ECU is the car’s engine computer. It reads sensors and decides how much fuel to inject and when to spark the plugs.

Term

ignition timing

"just such a powerful way of showing exactly what the ignition timing's doing to the engine torque. Interestingly Todd from Mainline upgraded us to their new Pro Hub firmware and it's lost that"

Ignition timing is when the spark happens in the engine cycle. If it’s too late you lose power; if it’s too early you can get knock and damage.

Term

data log

"Oh really? Well there's a different way of doing it with a data log so essentially there's a logger that's running the whole time and if you've got torque and ignition timing you can log those two parameters against each other and it'll show you that graph"

A data log is a recorded file of what the car/dyno measured during the pull. You can review it later to see patterns that weren’t displayed live.

Term

torque

"if you've got torque and ignition timing you can log those two parameters against each other and it'll show you that graph but at the moment"

Torque is the engine’s pulling force. Tuners care about it because it’s closely tied to how much power the car makes in the real world.

Concept

BOP balance of power

"...if you back in the day... it was a lot easier to get the cars to be kind of equal you know effectively BOP balance of power now or performance that was..."

Balance of Performance (BOP) is a racing rule system that adjusts things like weight, engine output, or other limits so different cars can compete more evenly. The speaker connects it to modern racing where technology makes it harder to “naturally” keep cars equal.

Term

cam timing table

"and trying to figure out what was the cam timing table it was like I have nightmares about it."

A cam timing table tells the engine computer when the camshafts should move. If it’s set wrong, the engine can run poorly or not make power. It’s one of the more sensitive tuning areas.

Concept

engine tuning

"...like obviously we do engine tuning we're also designing suspension components and we do obviously I do driver coaching..."

Engine tuning means adjusting how the engine runs so it makes more power or drives better. A tuner changes settings like fuel and timing so the car performs the way you want.

Concept

endurance racing

"...paid me to come because I I could both drive with him or or drive with the team if we were doing endurance racing but also would consistently like if we were having problems..."

Endurance racing is long-duration racing where the car has to last. It’s not only about speed—reliability and careful setup are just as important.

Concept

limp mode

"at the 24 hours of COTA where the car suddenly went into a limp mode like an hour into the race and no indication as to why it's just it's a factory race car"

Limp mode is when the car automatically cuts back power to protect the engine. It happens when the computer thinks something is wrong, so you can keep driving (slowly) or get back to the pits.

Concept

inlet temperature not shown on the display

"it didn't tell you what the inlet temp was on the display which is insane like you'd think of all the values that you would want to know on a turbocharged race car like that"

Sometimes the car knows something is wrong, but the driver screen doesn’t show the key number. If you can’t see the inlet temperature, you may not catch the problem before the car limits power.

Term

manuals

"[3216.0s] in we rented two rental cars so that we could both practice driving manuals and we got the [3220.3s] cheapest rental cars we could and you know my co-driver was paying for this stuff"

“Manuals” means cars where you shift gears yourself with a clutch. If you’re not practiced, it’s easy to shift at the wrong time and lose performance or stress the drivetrain.

Concept

oil pressure

"[3270.6s] what was happening is that the pan wasn't baffled very well so under braking it would lose oil pressure"

Oil pressure is how strongly the engine’s oil is pumped through the system. If it drops—like during hard braking—some engine parts don’t work correctly and the car can throw faults.

Term

wheel lockup

"[3642.6s] you see Formula One cars admittedly not very often but you see Formula One cars locking up a [3647.3s] front wheel coming into a corner well the answer is no they can't so yeah abs for me yeah"

Wheel lockup is when the brakes are so strong that a wheel stops turning and starts sliding. That usually makes the car harder to steer and can increase stopping distance.

Company

Bosch

"[3732.1s] lap time it is quicker it's interesting you say that because when the the deal we had with that [3732.1s] Bosch motorsport abs unit was we were given it by Bosch motorsport Australia and we're very open [3738.5s] about the fact that yes we were given a very expensive piece of equipment but also from the"

Bosch is the company that makes the ABS hardware used in racing. They’re saying they tested it and shared what they learned instead of just trusting marketing claims.

Term

compression ratio

"and there it's just stock stock engine 10.2 to 1 compression so it is scary in the sense that like if you're trying to push power right away on them"

Compression ratio is how tightly the engine squeezes the air-fuel mixture. With boost, higher compression can make knock more likely, so you have to tune carefully.

Term

rev limit

"now I think the stock rev limit on these is 7000 and I just had a car out this last weekend that we were pushing to 7800"

The rev limit is the RPM ceiling the car won’t normally exceed. It’s there to protect the engine, so raising it is something tuners do carefully.

Term

wall wedding

"The first time I was tuning [6553.4s] acceleration enrichment and the whole idea of wall wedding, I was like, this is crazy."

This sounds like a mis-heard term, but the idea is that fuel can “stick” to the inside of the intake for a moment. When you change throttle quickly, that stored fuel affects how much fuel the engine actually gets, so the tune has to account for it.

Term

commission

"...you use the ECU that the tuner you've chosen suggests. And they're not suggesting that ECU because they're making 40% commission on that versus 20% on something else."

Commission refers to a sales incentive the tuner or shop might earn for recommending certain products. The speaker explicitly addresses this concern, arguing that ECU recommendations aren’t primarily driven by commission differences but by professional capability and alignment.

Company

Haltech

"but at that time Haltech wasn't super popular in New Zealand. And I felt that those two products"

Haltech makes aftermarket computers for engine tuning. Tuners use them to control things like fuel and ignition, and the speaker is saying it wasn’t very common in their area at the time.

Term

plug-and-play harness

"So yeah, so we're doing Motec plug-and-play harnesses for these where you'll just be able to plug the thing in."

A plug-and-play harness is a ready-to-install wiring kit. It helps prevent wiring mistakes that can cause the car to run poorly or not start.

Term

air flags

"And every single time I logged into that ECU, it was like, oh, look, there's like 32 little air flags here."

“Air flags” are settings inside the engine computer that tell it how to interpret air-related sensor data. If they’re wrong, the car may not run correctly until the settings are fixed.

Concept

perceived value around price point

"[7574.6s] also I think if you're charging yourself out at a rate that's too low, there's sort of perceived [7580.0s] value around price point. So if you're charging out yourself too low, you're charging $500 [7587.7s] for a tune and everyone locally's $1,000, almost people look at that and are like, oh it can't [7592.2s] possibly be any good if it's $500"

People sometimes think “cheap must mean bad.” If your price is much lower than everyone else’s, some customers may assume the work isn’t good, even when it is.

Concept

charging for expertise vs time

"[7615.9s] No. And I think it is important to realize exactly what you just said, I had the same issue with [7621.3s] with feeling or putting in the time to solve problems and then you get, you fix the problem [7625.9s] and you're like, oh, well, I guess I should have known that, I should have done that first, you [7629.9s] know, only to realize that like, no, you had to go through the steps and it's unlikely someone [7634.7s] else could have figured it out faster. You got to charge for it. So. Absolutely. I think that [7639.5s] where that goes almost the other way though is where you come into a job and, you know, [7645.1s] someone's been driven crazy by this problem that no one's been able to fix and they've [7649.2s] poured hours and hours into it. So look at it, look through the thing and I know what the [7653.5s] issue is and you've fixed it in five minutes. And so what do you do? Do you build them for [7657.8s] the five minutes of time or the 20 years of experience that you've gained along the way?"

Sometimes you solve a problem fast, but you only can do that because you’ve learned from years of similar issues. The price should reflect that know-how, not just the time you spent that day.

Company

strongmotorsports.com

"And then our website, strongmotorsports.com, is where I'm probably going to hire a media guy soon because I'm not good at it. And I get so busy with the technical stuff"

They mention their website, strongmotorsports.com, where people can find what they do. It sounds like it’s connected to the tuning and products they’re selling.

Concept

VIP package

"don't forget by using the code podcast500 at checkout, podcast listeners can get a huge $500 off our VIP package which includes over 40 current courses as well as a long list of courses to be released in the future."

A “VIP package” is being promoted as a paid membership tier that includes a large library of courses and ongoing access. In the context of performance education, this implies structured learning (not just one-off videos) and continued updates via webinars and a community forum.

Concept

lifetime access

"As a VIP, you'll also get lifetime access to our members only webinars and our community forum. Lastly, we'd love it if you could leave a review or comment"

They’re saying you keep access to the content forever. That’s helpful because tuning knowledge changes, and you may want to rewatch or review things later.

Concept

engine building

"we are an online training school and we specialise in teaching a range of performance automotive topics. Everything from engine turning and engine building through to wiring, car suspension and wheel alignment, data analysis and race driver education."

Engine building means taking an engine apart and putting it back together (sometimes with upgrades) so it can make more power or handle harder use. It’s not just “bolt-on” work—there’s a lot of careful assembly involved.

Concept

wheel alignment

"Everything from engine turning and engine building through to wiring, car suspension and wheel alignment, data analysis and race driver education."

“Wheel alignment” is the adjustment of suspension angles (like camber, toe, and caster) to ensure the tires track correctly. Proper alignment improves tire wear, straight-line stability, and cornering consistency—especially important for performance driving.

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