Harrop TVS86 Owners Thread

[FunnyGopher]

Originally Posted by grumpysnapper

looks great, well done!

Given its the start of your Harrop journey, in the short term at least, you could think about going back to the standard throttle body and enjoy a really nicely well sorted system/tune, without the overun compromises etc?

So I did swap the OEM TB back on today after cleaning it and taking a dremel to the coolant hose barbs. After 10 minutes driving, I could tell it was already so much smoother. Tip in feel wasn't as harsh, the overrun is completely gone, and the transition to deceleration is not as aggressive. I was told I could probably make an aftermarket TB work if I were to have the car dyno tuned, otherwise it's just too difficult to get drivability nailed down. So I think I'll leave it on for now.

On a different topic, now that I've been able to play with the car a bit more, the difference between 90% throttle and 100% throttle feels like all the boost. Does the wastegate just dump everything unless my foot is on the floor? In partial throttle, just chillin', it feels like my car did before the charger. Only when my foot hits the floor does it scoot. I guess I felt it was going to be a bit more torque-y in higher partial throttle positions. What are all of your experiences with this?

[FunnyGopher]

Originally Posted by Mike_ZN6

I don't think there are a lot of gains to be made with a bigger throttle body on the FA20. Using the stock throttle body like your tuner suggested is probably the way to go.

I've never really wanted a larger throttle body (TB) for the gains. It's for the throttle response. I threw the Grams 72mm TB on my NA car and I loved it. It made negligibly more HP, but the throttle response was so much better. When I was planning to SC the car, I thought I might as well try to find a TB that matches the throttle port on the charger to take advantage of the throttle port size and let the charger be as efficient as it's going to be. You're right though, it alone wouldn't make a ton, but it would help make some up at the top while in the higher boost ranges.

I also knew a larger TB solution that works with the AC compressor really hasn't been shown and proven a ton in this forum, so I thought I'd try and find a good solution. Wam bam, I found that the Blox 70mm does fit with the AC compressor and works.

The problem for me is that the base maps that CSG has and works from when tuning this kit take into account the behavior of the OEM TB, and an aftermarket TB is going to behave differently. I was told it would be very difficult without a dyno tune to dial in correctly, not that it couldn't be done. Therefore if I desired smooth drivability when using the CSG tune right now, I should probably go with the OEM TB. And so far that statement has been very true.

[FunnyGopher]

Larger throttle bodies (TBs) create the potential to deliver more air to the motor. They themselves generate no power. They are a support modification. The motor is requesting air, the TB helps deliver that air. The motor will not ask for more air just because a larger TB is installed.

On this car when NA, previous research has shown that the OEM TB at WOT is not a restriction on this engine, even at the top of the RPM range. The OEM TB is completely sufficient in delivering all of the air the motor is asking for. Because of this, a larger TB on this motor in an NA configuration is mostly going to contribute to throttle response. You're able to deliver more air at partial throttle when the butterfly valve in the TB is partially open. More air at partial throttle is allowing the motor to make more torque. So with less throttle pedal the car will make more torque because more air is able to be delivered. Up top in the RPM range when in WOT, there's not a single difference, because this motor doesn't ask for more air than the OEM TB can supply at WOT, so the ability to deliver more air with a bigger TB is wasted.

On a pull through boosted application like the Harrop kit, because the compression of the air is happening after the TB, getting as much air through the TB is important for allowing the charger to create higher boost pressures. You can think of pull through boosted applications like a much bigger motor asking for air. The Eaton unit that the Harrop kit uses asks for 1.32L of air for every rotation of the rotors. From my rough measurements, when using the 90mm pulley, for every crank rotation, the rotors will have rotated ~1.5 times. That's ~4L, or ~2x more air volume than the displacement of the motor for every full engine cycle. The OEM TB is sufficient at delivering the volume of air needed for a 2L motor, but a 4L motor? The TB could probably use higher flow rate for that.

With even smaller pulleys, the rotors will rotate even more times per crank rotation, in which case the OEM TB will definitely become an air restriction when those rotors are asking for multiples of air volume more than the OEM TB ever had to deliver. With the 65mm pulley, it's essentially asking for ~5.5L of air. Installing a TB that at least matches the machined throttle port on the charger will help deliver the amount of air the charger is asking for, allowing it to more easily make higher boost pressures.

TB size is not as important on a push through application like a turbo or centrifugal SC because the compression is happening before the TB, pressuring the front side of the TB and increasing the effective flow rate of the TB. The TB will open and the compressed air will just fill the intake plenum with as much air as it can very quickly. A larger TB won't hurt, but it's effects are not going to be as dramatic because the pressure has already been made.

So does all this make a huge difference in my case? Probably not. The car still hauls ass regardless. This will make a larger difference to those who opt for higher boost pressures, displacements, or RPM limits. Harrop machined their own 75mm TB for their track car, but removed the AC. The Blox 70mm TB allows you to keep the AC and still run a significantly larger TB that you can buy off the shelf. I probably can't use all the benefit right now, but that doesn't mean others can't. I'm just glad I found a solution and now maybe others can benefit from it.

[grumpysnapper]

Originally Posted by FunnyGopher

On a different topic, now that I've been able to play with the car a bit more, the difference between 90% throttle and 100% throttle feels like all the boost. Does the wastegate just dump everything unless my foot is on the floor? In partial throttle, just chillin', it feels like my car did before the charger. Only when my foot hits the floor does it scoot. I guess I felt it was going to be a bit more torque-y in higher partial throttle positions. What are all of your experiences with this?

No you are right, it should feel a lot more linear than that.

[FunnyGopher]

Originally Posted by grumpysnapper

No you are right, it should feel a lot more linear than that.

Okay, I'll see if I can get a log where I have the throttle around the border of where I feel all the boost kicks in and ask my tuner about it. I'm sure we could watch manifold pressure and if it's not anywhere close to where it should be at 90% throttle, then something might be up with my waste gate?

[FunnyGopher]

Originally Posted by grumpysnapper

No you are right, it should feel a lot more linear than that.

So, I had a sneaking suspicion it might have just been my driving. I went out to log last night and decided to find the longest flat road I could and just slowly move the pedal throughout the entire pedal range. It was 100% linear. I do feel, however, that 0%-60% felt similar, then everything up from there was progressively stronger as boost rolled on. So this tells me the wastegate was bleeding enough off until ~60% throttle to feel the same throughout that whole range.

[grumpysnapper]

Originally Posted by FunnyGopher

So, I had a sneaking suspicion it might have just been my driving. I went out to log last night and decided to find the longest flat road I could and just slowly move the pedal throughout the entire pedal range. It was 100% linear. I do feel, however, that 0%-60% felt similar, then everything up from there was progressively stronger as boost rolled on. So this tells me the wastegate was bleeding enough off until ~60% throttle to feel the same throughout that whole range.

That sounds more like it, at the end of the day its still a small motor that needs a decent amount of revs (particularly without a smaller pulley) to get properly motivated.

[Kiske]

Still nothing on the Gen 2 revision?

[YCK]

Originally Posted by Kiske

Still nothing on the Gen 2 revision?

I have been waiting for the FA20 version to be back in stock for quite a while... I noticed Harrop pulled out all the info about the FA20 supercharger from their website a while back so I sent them an e-mail asking if it is officially discontinued now so I can move on... They replied promptly and said they are working on a version that will work for both FA20 and FA24 but they didn't have an ETA or pricing. I am guessing the fact that the ECUTEK support for the FA24 is not yet available is not helping if they are tying the release of the updated hardware to the new engine.

[ojuniour]

I'm not sure what's going on..but my tuner tried as much as possible to getmy power up to 300whp but to no avail...And I'm running 85mm pulley. I could only get to 260. and on e85 (~60) I could only muster up additional 20whp.
Although it was brutally hot during that day.. close to 100. but still That's very underwhelming right now.

Can anyone explain why? Is it because it's a mustang dyno? I was expecting at least around 300 with 85 mm pulley on 93 and close to 350 on 85.

[Brz-123]

Originally Posted by ojuniour

I'm not sure what's going on..but my tuner tried as much as possible to getmy power up to 300whp but to no avail...And I'm running 85mm pulley. I could only get to 260. and on e85 (~60) I could only muster up additional 20whp.

Although it was brutally hot during that day.. close to 100. but still That's very underwhelming right now.



Can anyone explain why? Is it because it's a mustang dyno? I was expecting at least around 300 with 85 mm pulley on 93 and close to 350 on 85.

Harrop only claim 244 HP at the hubs on a dynapack dyno on 95 mm pulley. WHP will be lesser.

260 on a 85mm seems fair to me. Each car/ engine could be +-10 bhp and mustangs read conservative anyway

Sent from my SM-G781B using Tapatalk

[RedReplicant]

As always, a dyno is a tool, not to be used for comparison and the peak numbers somewhat meaningless without context.

With that said, if you use a dynojet with the same correction factor / smoothing NASA specifies for classing dynos (https://nasa-assets.s3.amazonaws.com...m--3-14-22.pdf) you can get kind of close to a comparison with other people tested using the same config. If you have NASA people in your area then there will be shops that will probably do 3 classing pulls with them overlaid and the RPM printouts for $80-120.

The two dynos I posted were done in this config.

Also, supporting mods?

[FunnyGopher]

Originally Posted by ojuniour

I'm not sure what's going on..but my tuner tried as much as possible to getmy power up to 300whp but to no avail...

Hmmm. I haven't had mine dyno'd yet, but on 90mm pulley and E85, my butt dyno is definitely telling me at least 300. Zach from CSG told me for my goal of ~320whp, the 90 or 85 would get me there easily, but I have all the goodies installed to get me there. I believe Replicant also had a dyno chart showing a conservative 85mm tune and also reached ~320 with all the goodies. Temps here are similar, if not hotter. I'm with Replicant, what supporting mods are installed?

[Mike_ZN6]

Originally Posted by ojuniour

I'm not sure what's going on..but my tuner tried as much as possible to getmy power up to 300whp but to no avail...And I'm running 85mm pulley. I could only get to 260. and on e85 (~60) I could only muster up additional 20whp.
Although it was brutally hot during that day.. close to 100. but still That's very underwhelming right now.

Can anyone explain why? Is it because it's a mustang dyno? I was expecting at least around 300 with 85 mm pulley on 93 and close to 350 on 85.

What headers are you running?