Sprint Booster installation (and testing)
 

Overview

A caveat. I don't know a lot a about the inner workings of motor vehicles... :)

I did a lot of research on any performance chips that might be available for the E70 4.8i (as I'd had performance chips in my previous 325is and 328i). There are a couple available in Europe for the E70 3.0si and there is one for E70 4.8i from Hamman (which I would classify as a reputable company). That requires 98 octane fuel so I had to forget that option (in the USA). So there is no USA option for boosting HP or torque (from reputable manufacturer).

I really wanted to see if I could improve throttle response though (as the HP and torque in the 4.8i is actually fine). Sprint Booster's Throttle Enhancer was the obvious one as it's been discussed on many different BMW & MB forums. There are people that are very happy with it and there are others that have problems with it or claim that it falls into the same (useless) category as the "Tornado Air" (which supposedly increases MPG). The Sprint Booster price has come down to as low as $300 and is carried by reputable companies such as ECS Tuning, Turner Motorsport, Bimmerworld, Bavarian Autosport, etc. Some are offering a 30-day money back guarantee. Another product, that appears to be a similar to the SB, is the G-Power BMW E-Response Module. I asked Jace Tuning why the product was $1,003 compared to the Sprint Booster but never got a response from them.

I decided to try the Sprint Booster and purchased that.

Installation

Unfortunately, installation was not as easy as the single instruction sheet showed. The instructions for removing the throttle pedal assembly were for a totally different model of car and did not work for the E70. After some searching, I found some instructions which helped. This is my version:
1. Remove floor mat
2. Flip up black plastic button at bottom of pedal with small screw-driver (see pic 1)
3. Remove allen bolt holding bottom of pedal
4. Lift throttle pedal up (from bottom) and wriggle it a bit while doing that
5. In pic 3 you can see the clip that was holding the throttle pedal in place (along with the allen bolt at the bottom)
6. I haven't attached any pictures of attaching the Sprint Booster install as those are straight forward and covered in the instructions
7. In pic 4, you can see what it looks like after the Spring Booster is installed. It looks ugly and there is no excess cable on the SB to tuck that up under the dash (as I had hoped to do and that others with other BMWs had been able to do). Maybe there's different model that has longer cabling -- I had supposedly received the correct SB for the automatic X5 though
8. In pic 5, I had temporarily put the little switch where you see it. There are three settings (light off = Stock, green = Sport, red = Race)

Testing

I put it into Sport mode. Pressed the gas pedal. The X5 jumped and lurched forward! I had to learn to drive differently. The throttle response improvement was FANTASTIC! I had to gently touch the gas pedal and I got IMMEDIATE throttle response and only had gently depress it further to accelerate fast.

So this was a good thing for normal driving around town but that's not where I found the real benefit. It was on the freeway driving at 70 - 80 MPH and above. When driving at those speeds, overtaking was RIDICULOUSLY SMOOTH and RESPONSIVE. If I was in the #2 lane and wanted to move over quickly, between two cars, into the #1 lane, I just slightly depressed the throttle and got immediate and smooth response. None of the "mashing the pedal to the floor" and the resulting lurching.

So for freeway driving especially, I felt like I was driving a different vehicle :) I hardly pressed down on the throttle at all and it was very comfortable to drive. There was no negative effect on my MPG in the time that I tested it.

Negatives

The negatives are
1. The Sprint Booster switch being right above the throttle pedal assembly
2. The red "Race" mode is unusable as the car jumps forward at the slightest throttle touch
3. The "Sport" mode or the green light does not switch off when the car is switched off
4. If another driver, who doesn't know about the Sprint Booster, drives your car with it in Sport or Race mode, they could easily be overly surprised with the throttle response and cause something bad to happen to the car's front end
5. It will most likely affect the warranty. But is quick and easy to remove -- only 5 minutes work.

Why I've removed it

My X5 has the Active Steering w/Servotronic Power Assist option. This adjusts the front wheels' steering angle in proportion to the car's speed. In low speed, the front wheels respond immediately to small movements of the steering wheel (parking and driving in tight spaces is enhanced) while at high speeds, it gives more precise steering, great stability and more comfort (which results in it being very easy keep the car exactly in the lanes and less tiredness when driving long distances).
I found that the Sprint Booster made my Active Steering no longer work :( I first noticed something different when in town; I could feel the steering (unpleasantly) different. On the open road, this difference became a lot more apparent. It took more effort from me to stay in the lanes (as I'd lost the stability enhancement) -- it was obvious that Active Steering was no longer working. Everything else seemed to be working just fine.

So I've uninstalled in and hopefully the supplier will stand by his 30-day money guarantee...

Interesting write up.

So now that you've removed the SB, has your active steering returned to normal?

I'm surprised this product had any effect on the active steering (which I thought was dependent on actual vehicle speed, not throttle setting).

The Sprint Booster sure looks like snake oil to me.

It appears to do nothing more than remap the response of the throttle relative to the position of the accelerator pedal so that the throttle opens faster at the beginning of the pedal travel. This is nothing you couldn't accomplish on your own, simply by pressing the pedal faster. It's not surprising that it has the unpleasant side effect of making fine modulation of the throttle at low speeds difficult.

doesn't sound all that different from DS mode...?

Brian5, thanks for the post and pictures.

I am interested in this product and have read more reviews and posts on it than I care to admit. Overall, the reaction seems mixed and is mostly centered around "a faster car" versus a "more response and linear pedal feel." At the end of the day I think the intent for the product is a more responsive / linear feel to your accelerator than a faster car. At least that is what I am after; no interest in a "faster" car.

So, if we put that argument aside, your comment about disabling your active steering is obviously a concern. I have read other posts that made no mention of this issue but there were a few other abnormalities mentioned here and there but nothing consistent.

Wouldn't any downside of this nature be consistent across models (assuming the same options, i.e,, active steering)?

Any other comments or insight from anyone on the topic?

Couple of answers:
1. After removing the Sprint Booster, my Active Steering has returned to normal. I have not read of ANYONE else that has experienced this particular problem (and I did a lot research before purchase).
2. No, it's not "snake oil". Read my earlier post for what it claims to do. It does what it claims to do.
3. No, it's nothing like DS mode.

After having installed and removed it, I can see that it can be a pretty quick operation to do that. I do NOT recommend the Sprint Booster (at least for the E70) though. I have listed most of the reasons in my earlier post. Some more reasons are:
6. It would be a real hassle to remove it and re-install every time you take the car in for service under warranty.
7. You would have to hide the switch, that switches between the 3 modes, before anyone else not familiar with the SB drives your car -- the SB could be dangerous to anyone unfamiliar with the car. This could be auto shops, valet services, etc.

If you have an older BMW, I suggest looking at a different option to increase the torque/HP instead. Having said that, I could see that a SB might help a small car like the 328i to be more responsive. I drove a new 328i loaner recently and I could not believe how sluggish it was.

Just an FYI. European 98 octane is the same as our 92 or 93 (I cannot remember which).

I can't dispute that as I haven't looked into it.

I can tell you that Hamman Europe told me that they don't sell their performance chip in the USA because it requires 98 octane fuel.

They told me the same thing about a chip for the X5M. Even though I argued it is the same engine.

I don't believe that to be the case.

You can't actually convert from one octane number to the other unless you can test the fuel. You can approximate the other octane number though, and 6-7 points is a reasonable estimate of the difference.

Euro rating is based on the Research Octane Number (RON).
Another standard is the Motor Octane Number. This uses a different test protocol than the RON method. One focuses on higher engine speeds, the other on lower engine speeds, as I recall. Edit: I looked it up, and the RON test is run at 600 rpm, while the MON test is run at 900 rpm. Since we don't spend much time with our road vehicles at those engine speeds, it shows the theoretical nature of the octane ratings.
North American Antiknock Index (AKI) is calculated as (R+M)/2, so it is the average of the two tests. However, two fuels with the same RON rating may have different MON numbers, and so have resulting different AKI numbers.

All that said, 98 RON is pretty close to 93 AKI in the real world.

You are touching on why the Sprintbooster causes controversy and gets tags like 'snake oil' on this and other forums.

For my part, I understand completely that it changes the throttle pedal mapping, and can thus change the feel of the throttle. That is perfectly logical, and in that sense it is not snake oil.

However, the Sprintbooster is often claimed to increase horsepower. That is when many of us snort in derision, and use phrases like snake oil, because the throttle pedal doesn't control how much horsepower an engine makes. If it did, we wouldn't need turbochargers, we could just install larger gas pedals to improve 0-60 times. It may feel like the vehicle has more power, but logically, it can't.

Your quote above may leave some readers believing that for older BMWs, the Sprintbooser may be an option to increase horsepower and torque.

Good post though, interesting to read. Thanks for putting it up.

JCL,

I said "....If you have an older BMW, I suggest looking at a different option to increase the torque/HP instead." and you responded that "Your quote above may leave some readers believing that for older BMWs, the Sprintbooser may be an option to increase horsepower and torque."

I've made it clear and I'm pretty sure that you'd find that most resellers are NOT claiming horsepower or torque increases. I agree that lots of uninformed people may have got that impression -- but not from what I posted. They'd have to be pretty slow to think that HP or torque gains are possible from the SB.

I probably could have just changed it slightly to say "....If you have an older BMW, I suggest looking at an option that will your increase the torque/HP instead of SB (which only increases the throttle response)."

BTW, As much as people like to malign the SB, it's still nothing like the "BMW X5 performance chips" on eBay that make claims like this $25 product:

MUCH DIFFERENT! Huge difference!

Brian - I just realized you bought version 2. I have the old version, which doesn't have a switch to change between race and sport. On my M5, I just have the M version, which doesn't have a switch either. It's just designed more around the power band of the M models.

Sorry to hear it didn't work out. I absolutely LOVE the Sprint Booster and have had them in many of my BMW's over the years.

Let me also state that the Sprint Booster DOES NOT increase HP or TQ. It just removes throttle lag. For those familiar with throttle lag and how annoying it can be at times, this is your solution. If you have an ECU remap, that too, removes throttle lag, but I will tell you that the Sprint Booster essentially makes it non-existent. I have and had ECU tunes on my BMW's and tested the cars with and without the SB. The SB still made a huge difference. I'll never not own one.

Ah, no!