HKS SLD (Speed Limit Defencer)

[macbuddy]

What do you make of this device? It is called the HKS SLD (Speed Limit Defencer) (http://www.hksusa.com/products/?id=781)
http://www.hksusa.com/images_products/S_2129.jpg
I have been looking for a way to raise my Fit's rpm rev limiter. This looks like a possible solution. The only problem, is that this totally eliminates the rev limiter. It does not allow one to dial in an alternate rev limit ceiling. If this device does what it says it will, what would the consequences be if we occasionally over-rev our little 1.5 engines? Do you think that we could safely rev to 7,500 rpm?
From what I see, PN: 4502-RA002 is a Type 1 (for manual transmissions), PN: 4502-RA003 is a Type 2 (for auto transmissions). I discovered this device through a post made by mgutt.

[claymore]

Whew that is a tough one. Look at the turboed one on the freak site with a messed up piston. Fit connecting rods are in no way beefy and can stretch besides being not the strongest in the world. Combine high RPM, rod stretch, and interference type heads and you are asking for trouble.

As to could you even control it I have a hard time not bouncing the limiter with a stock engine when pushing hard in first gear going into second it comes up so fast it's very easy to hit the limiter before shifting. Do that a few times with no limiter and you are heading for disaster.

With the size of our intakes and port limitations any gains gotten over stock redline would be minuscule at best. Could you do it a couple of times .... probably... is it worth a blown engine for possibly ONE horsepower doubtful.

In mgutt's case he is looking to get rid of the car speed limiter not the engine speed limiter because of unlimited speeds are legal in his country but the JDM ECM he has is limited to 188kph for use in Japan which limits all cars to that speed

[manxman]

I agree with claymore. As excellent as the Fit may be in its unique design, the drive train is just good enough to not blow up or fail when the car is used for its normal, advertised purposes, at least during the warranty period. If the engine were strong enough to withstand higher rpms, the rev limiter would not be there in the first place.

[macbuddy]

Thanks for the input. You guys just saved me another $170...and maybe more!

[claymore]

Glad we could help you out that is what we are here for :p

But IF you had a custom engine that had stronger High Performance parts installed and had a better cam etc. Higher rpm does offer some increase in power because at higher Rpm the engine is putting out more power strokes per minute than at a lower rpm. So the conundrum is is buying all the extra parts worth the amount of extra power you are going to get vs the greater chance of blowing that engine.

It must work because the Formula one engines turn in the neighborhood of 18,000-20,000 RPM :eek:

[manxman]

Thanks for the input. You guys just saved me another $170...and maybe more!
We saved your CAR- hee hee hee.

[macbuddy]

...I have a hard time not bouncing the limiter with a stock engine when pushing hard in first gear going into second it comes up so fast it's very easy to hit the limiter before shifting.
I totally agree, redline comes up way too fast when I am in a hurry. In all my previous cars/motorcycles, I used to shift by the "feel" of the engine. The Fit's engine revs so "willingly," that it "feels" like it wants to keep on revving. It "feels" like it is still pulling, when the rev limiter prematurely steps in. It "feels" like it has more to give!
Even after 4 years, and 110K miles of ownership, I continue to struggle with that ~6,500 rpm limit every time my adrenaline kicks in. This has been a real problem during AutoX events. I tend to hit the limiter quite often.
When I run mrFroge's HS Fit on extremely tight courses, I sometimes post better times by just leaving the 5AT in 1st gear and drive on the verge of bouncing off the rev limiter, rather than trying to constantly shift back and forth between 1st and 2nd gears. I have yet to master those "paddles" fixed to the steering wheel. Shifting UP and/or DOWN can get downright confusing when your arms are all twisted up, while trying to power out of a decreasing radius turn!
The point here is that I lose time, every time the limiter steps in. I thought that if I could safely raise the limit, I could have a more drivable car, and ultimately post better times.


It must work because the Formula one engines turn in the neighborhood of 18,000-20,000 RPM
Whoa! That's spinning over 333 revs per second!

We saved your CAR- hee hee hee.
LOL!...and mrFroge's CAR too!

[manxman]

I learned back in 1970-71, with my Sunbeam Tiger at Riverside and Ontario raceways, that you can't truly be competitive in your DD. You aren't going to win unless you can afford to break the car. mrFroge is anomalous to my statement, but in most cases, my statement is true.

If you had a spare Fit for track use (or spare engine and the time to do swaps when necessary), you could buy one of those black boxes that does away with the rev limiter, and see if the extra available revs would give you the edge that you want without leaving a connecting rod or two in a big pool of oil on the track.

But------- most important--- the box would disqualify you from stock class. And WHEN it destroys your engine on the road, you will be a looooonnnnggg way from home.

[macbuddy]

Yeah, I think about that every time I compete. The coilpack episode that I had recently only supports such fears. I have learned that some parts fail without warning.
Even breaking down two blocks from home is still a long way to push a 2500 lb. car.

[mgutt]

Its useless for revs but not for speed limit. I'm driving often more than 180 km/h and the limit is a pain.

And as I know it doesn't remove rev limits:
http://www.hksusa.com/products/?id=781