Harrop Smoothie D-Box? and misc issues
 

Heyo - does the Harrop supercharger kit require a Smoothie D-Box like the Edelbrock kit?

Also... are there any known issues with the Harrop kit? Reading through all the ownership threads. It looks like

Edelbrock bypass valve is known to fail (repeatedly)

JRSC Rotrex unit reliability is iffy

Are there any issues with the Harrop kit I am missing?

D-Box: I haven't heard of anyone of the Harrop customers using one. In fact, I am of the opinion that the pressure pulses can be reduced significantly and pneumatically by using a remote-mount MAP sensor with a pulsation dampening chamber inline with it.

I am currently in the middle of experimenting with certain parts and materials to address this and have a working prototype, but I have yet to install my Harrop on my car yet to test it out.

As for any known issues: I haven't heard of any. It seems to be as reliable as a Lexus, which is one of the main reasons that I chose it for my car.

Haha I just went to this subforum to check on your progress and found this thread. I guess it is still in development.

To the OP, I don't know of anyone with issues. The kit suffers the same issue, but maybe less because the sensor is lower in the runner. It can be sorted with tuning or with a mechanical filter, but otherwise, it isn't really a major issue. I don't have the Dbox.

Harrop doesn't need a D-box. Neither does the Edelbrock, with CSG tunes.

Edelbrock's bypass has been incremented and is no longer an issue

JRSC Rotrex kits are easily THE MOST Proven kit on the market. The most popular kit is bound to have the most failures because there's more of them out there. As an actual percentage, failure rates are tiny.

I reached out to Neal @ Racer's Line who helped develop the CARB tune (I learned). He informed me that the Harrop kit uses a separate IAT sensor and the stock MAP sensor so it does not require a smoothie box.

Hey Mike, I'm inclined to believe you given your experience.

In terms of reliability do you think the C38 running on a CARB tune would have a longer life than a C30? Because it's not being stressed as much? Waiting for a new unit from overseas on top of a warranty claim just seems like a huge headache I would like to avoid.

Those bearings are designed to spin at high RPM. There is no "less stress" with the C38, but I do see units frequently go under-maintained.

Undermaintained as in not changing the oil every 50,000 miles? I thought Rotrex was maintenance free outside of that

or 2 years, and making sure the fluid level doesn't get low.

Many folks don't do that.

It depends on the tuner, what the tuner is using to do their tune and your setup. Some tuners prefer to tune off a MAP sensor, and I don't know the limits of the MAF sensor for tuning. Maybe it has no limits, but I bet there is a limit.

From what I understand, the Harrop kit uses the stock MAP sensor and is running a tune off the MAF readings. The stock MAP isn't really designed for boost, so anyone getting a tune based on the MAP sensor needs to upgrade, which was me, and because I am running more than the stock pulley, the entry level MAP sensor at 11psi wasn't enough, so I am on the 45psi sensor.

The downside is that the MAP sensor does see fluctuations, which I hear tell from others can be tuned out like Mike said, but I don't know if all ways of tuning it out is the same or equally safe or possible at all boost levels or whatever. Best thing is to find a tuner, and then ask them.

Uh, your tuner specifically had me make a remote MAP sensor adapter for my Edelbrock tune due to large pulsations that even the D-box couldn't pull out. It made a huge difference.

What do you make of the 100k Edelbrock oil change interval? Seems sketch to me tbh.

I'm lame and would probably just use the CARB tune for whatever kit I choose.

Got a picture of your setup?