Harrop TVS86 Owners Thread

[FR-S2GT86]

Originally Posted by Irace86.2.0

The stock map sensor only reads like 3psi, but the Harrop CARB tune is based off the MAF, so that is how they get away with that. If you want to run a custom tune then check with your tuner. Delicious Tuning, for instance, uses the MAP sensor, so they would need you to purchase a larger map sensor.

Also, the CARB tune is off the 8psi 95mm pulley. The 85mm pulley yields 11.5psi.

Just realized the typo, I meant to write 95 mm. Edited my post above.

Ah, I see. Thanks for the info on Harrop using the MAF sensor instead of the MAP sensor in their tune. I went ahead and ordered a 2.5 bar Omni MAP sensor to have on hand for my trip back up to Cincinnati for the flex-fuel, bigger injector and 85 mm pulley custom tune after I install the Harrop kit with their CARB tune.

Just received my economic stimulus payment today, so I know exactly where that's going.

[Kodename47]

Unless you max out the MAF you don't need a larger MAP and in most PD blowers I've seem (not seen the logs of a Harrop for some time) the pressure wave resonance in the manifold has a negative impact on a wider range sensor that the OEM one isn't able to detect, hence it will run better on the OEM sensor. This is why many recommend the D-Box but is actually able to be mapped out quite easily on EcuTek.

[Irace86.2.0]

Originally Posted by Kodename47

Unless you max out the MAF you don't need a larger MAP and in most PD blowers I've seem (not seen the logs of a Harrop for some time) the pressure wave resonance in the manifold has a negative impact on a wider range sensor that the OEM one isn't able to detect, hence it will run better on the OEM sensor. This is why many recommend the D-Box but is actually able to be mapped out quite easily on EcuTek.

Again, of course, that will require a tuner that tunes off the MAF. Tuners with canned-custom-revisioned-tunes based only on MAP input will likely require an upgraded MAP sensor. I can confirm the the Harrop kit does suffer the same resonance as the Edelbrock kit, but it could be to less of an extent because the MAP location is close to the runners. I don’t know if the DBox works on the Harrop kit, but it could do the same to smooth out the signal in theory like you said.

Questions: If a tuner had both inputs, would it be better? My intuition is no or the DBox wouldn’t be necessary, but maybe it is a matter of it being used. What’s the limit of the stock MAF?

[FR-S2GT86]

It would seem to me that installing a small chamber, maybe the size of a fuel filter, between the pressure port of the supercharger and the MAP sensor, would reduce the pressure pulses and the resonances and which would, in return, smooth out the electrical signal. The size of the chamber can be experimented with to find the right amount of "muffling". I don't think a $350 electronic box which simply smooths out the electronic signal is necessary when a simple inexpensive mechanical fix would work.

As for the limit of the MAF sensor, I believe Kodename47 was involved in a similar discussion here:
https://www.ft86club.com/forums/showthread.php?t=106496

where Yobiwan was using a MAF sensor from a Forester with a higher limit. He posted some of his findings, but I don't have a way to read them. I looked a bit on EcuTek's site to see what the actual limit is for our OEM MAF sensor, like I did for the MAP sensor, but haven't found it yet.

I do believe that the more, accurate and usable sensor inputs that a tuner can use, the better the tune and the resulting performance will be.

[Calum]

Originally Posted by FR-S2GT86

It would seem to me that installing a small chamber, maybe the size of a fuel filter, between the pressure port of the supercharger and the MAP sensor, would reduce the pressure pulses and the resonances and which would, in return, smooth out the electrical signal. The size of the chamber can be experimented with to find the right amount of "muffling".

That's exactly how damping is introduced into a pneumatic signal in pneumatic control systems. It can be plumbed in series or in parallel. In series allows you to put a needle valve on the outlet to get finer control of the damping.

[FR-S2GT86]

Originally Posted by Calum

That's exactly how damping is introduced into a pneumatic signal in pneumatic control systems. It can be plumbed in series or in parallel. In series allows you to put a needle valve on the outlet to get finer control of the damping.

Yes, and it would be a lot cheaper and simpler to build. And it would be universal to ANY F/I application depending on the materials used. You probably wouldn't want to use rubber hosing to connect everything with 20 psi of pressure on it. But if you were to use hard plastic or copper or aluminum tubing.....

Edit:
Do I win anything for having the 1000th post on this one topic?

[sw20kosh]

Originally Posted by Rich196

Thats some ducting, what did you make it out of and do you have any data on the effects it had?

aluminum

all temps are cooler than expected

190 F ECT
190 - 220 F Oil T (somewhat varies with ambient)
IAT varies with ambient but no more than 35F above ambient with 70 mm pulley (throttle limited to 13 psi)

[Irace86.2.0]

I ordered my CARB tune today!

[Kodename47]

Originally Posted by Irace86.2.0

Questions: If a tuner had both inputs, would it be better? My intuition is no or the DBox wouldn’t be necessary, but maybe it is a matter of it being used. What’s the limit of the stock MAF?

5V......

OK I'm being silly, but the size/design of the intake will vary what the MAF reads for any given volume, hence the need for MAF scaling. The stock ECU uses a combination of MAF and MAP, I would assume there is some multiplier for MAP but I've not seen anyone, including EcuTek determine the logic. Hence why fluctuations cause interesting fuelling and less than optimal power. I also reckon that if you went pure SD or relied purely on the MAP for custom mapping then you're only going to get this or worse as there is no MAF basis to damp it out.

Here's a Cosworth SC, top is with Custom Map fuel smoothing, bottom is using the ECU's own fuelling strategy. You can see where the MAP signal starts to become erratic.

[Irace86.2.0]

https://datazap.me/u/jirace/more-log...-30&zoom=0-158

Same thing:

[FR-S2GT86]

So pneumatically smoothing out the pressure pulses before they get to the MAP sensor would be beneficial in ANY tune where the MAP sensor input is used. Does everyone agree? I'm trying to convince my tuner of this before I allow him to custom tune my engine.

[Irace86.2.0]

Originally Posted by FR-S2GT86

So pneumatically smoothing out the pressure pulses before they get to the MAP sensor would be beneficial in ANY tune where the MAP sensor input is used. Does everyone agree? I'm trying to convince my tuner of this before I allow him to custom tune my engine.

So you want to buy or 3D print something that would fit between the sensor and the manifold, or do a remote sensor like the hose I have off the back of my supercharger going to my boost gauge, but instead goes to the sensor?

Some boosted engines have map sensor filters supposedly to keep oil out of the sensor. It might have a dual action of smoothing out the signal. What do you guys think?

https://www.performancedieselinterco...-sensor-filter

[itschris]

Originally Posted by Irace86.2.0

I ordered my CARB tune today!

Speaking of, when you have multiple tunes w/ Ecutek does switching between them also switch the CVN? And if the first tune is selected, does having a second tune also available effect the CVN when the first is selected?

[FR-S2GT86]

Originally Posted by Irace86.2.0

So you want to buy or 3D print something that would fit between the sensor and the manifold, or do a remote sensor like the hose I have off the back of my supercharger going to my boost gauge, but instead goes to the sensor?

Some boosted engines have map sensor filters supposedly to keep oil out of the sensor. It might have a dual action of smoothing out the signal. What do you guys think?

https://www.performancedieselinterco...-sensor-filter

Yes, that's pretty close to what I was thinking of.

I found this during my research.

It's called the Pulse Plus built by REOTEMP which appears to be exactly what would be needed. I just found it last night and haven't looked at prices or tried to contact them as to where they can be obtained, but this device should work to solve the problem.

Here's a link to their website:

https://reotemp.com/pressure/diaphragm-seals/