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Aerosport Power IO-375 users…

rsr3

Well Known Member
I’ve been in touch with ASP and their IO-375 looks very tempting. I also really like the idea of the build school. I’d be interested to hear from owners / operators of the engine, specifically with respect to differences / difficulties of installation compared with the Lycoming M1B that Vans sells.

Either a post here, or if you prefer, PM me and I’ll send you my email.

Thank you!

Rob
 
IO-375 experience

I installed an ASP IO-375-M1S in my RV-7 during the build in 2010. I now have 8-1/2 years / 919 hours on it - so a fair bit of experience.

As far as installation differences, I think it depends on which sump and cylinders you specify. Back when I ordered mine, you could choose to have it built with mostly ECI parts or mostly Lycoming parts. I specified ECI parts and the ECI nickel tapered fin cylinders. (Note: the engine actually came with ECI, Lycoming, AND Superior parts!) The tapered fin cylinders require you to modify the standard Vans baffles. Not terribly difficult, but a bit fiddly. At the time, you could also specify the Superior "Cold Air Sump" - which I did. This required me to fabricate some custom brackets for the throttle cable and the mixture control bell crank. I believe this sump can also affect your exhaust system. Vetterman I think wants to know if you are using the Superior sump. I used the Vetterman 4-pipe exhaust which pretty much stays away from the sump. I think those are pretty much the only installation differences you will get into. Basically its a parallel valve IO-360 with a stroked crankshaft - and it fits like an IO-360.

You didn't say which version of the -375 you were considering. Back when I ordered mine you could get a low compression version or a high compression version (8.0 vs 9.6). At the time, both used the same, undamped crankshaft. It was strongly recommended to use only composite propellers on the high compression version due to possible torsional vibration issues. I don't know what ASP is currently offering, but I ordered the low compression version and have been using a Hartzell Blended Airfoil Prop with no issues.

As far as operational experience is concerned, frankly it has been a bit mixed. I have been a bit disappointed with the performance power-wise. Speed and climb rate numbers for my RV-7 are pretty much right on the money with Vans numbers for the 180 HP 360 engine - so no apparent benefit from the extra cubes and $$. Oil consumption with the ECI nickel cylinders was always on the high side with the oil turning dark within about 5 hours after an oil change. When the consumption got up to about 5 hrs/qt, I changed out the ECI cylinders for brand new Lycoming cylinders around 580 hours. After break-in, oil problem solved!

Caveat/Disclaimer: The above is my experience with the 2010 version of this engine. Your mileage may vary.
 
Hi Dan.

Thanks for the reply… I’d be going low compression “M1S” for future-proofing, and also am fairly set on the MT 3-blade.

I’ve been quoted for Millennium cylinders, so I’ll ask the question as to whether they’re tapered fins or not. I’ve flown aircraft in the past with millennium cylinders but have never looked at them in great detail.

I’ve received a private message along the similar lines to yours (without the oil consumption issue) so on the face of it, it doesn’t sound like too wild a suggestion for a first time builder with little knowledge of anything firewall forward wise.

I must admit the extra 15 horses hold some appeal.

Thanks again,

Rob
 
I have an IO375, 8.3:1, dual PMags, nickel carbide cylinders, ECI tapered fins, Superior cold air sump, 13 row oil cooler with damper on the firewall, and Vetterman 4 pipe exhaust. At 330hrs I'm happy with the performance and reliability. It does burn a bit of oil - 7.5 hrs/qt since day 1 and the oil gets black pretty quick.

Only installation changes I recall was in the baffling for the tapered fins, a custom throttle cable mount and slight mod to the mixture cable mount - no big deal.

When I bought the engine in 2013 crank dampers weren't offered. I flew it with a Hartzell BA for 300hr without any issue but changed to an MT-9-B/183-50a out of an abundance of caution.
 
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I installed a ASP IO-375 M1SC with 9.0:1 pistons, counter-weighted crank, Superior Cold Sump. System32 EFII. MTV-9 prop.
80 hours flown since new in the last year.

The Vetterman Trombone exhaust fits perfectly with no issues.
Straight finned cylinders, no baffle or cooling issues. (Do the #3 cylinder baffle mod by adding a few washers).

If you choose a B&C starter, you'll have to trim and re-glass the Van's snorkel to fit around the larger than standard starter. I also enlaged the snorkel's opening that mates to the EFII throttle body so their sizes matched.

To attach the Throttle Cable, I used a bracket sold by ShowPlanes (that I custom trimmed to fit) mounted to the bottom of the Superior cold air sump.

One thing to know is that I chose to use a 13 row oil cooler fitted with the ShowPlanes Thirteen Row Oil Cooler Mount with its Air Control Valve. 13 rows is more than enough oil cooling. At typical cruise speeds in canadian summer temps, the air valve is typically open only 1/2 - 3/4 inch to have oil temps in the 180-190F range. It's open about half-way for extended 130KTAS cruise climbs. These days, flying at below freezing with the cowling inlets almost half blocked, it's fully closed to get 180F.

So outside of the snorkel and the Throttle bracket modifications the installation was very straightforward as the weight and size is similar to a IO-360.

Compared to a 360, I arguably have a 15 - 20 extra HP on hand (maybe a bit more due to EFII). Needless to say that the acceleration and climb rates are stellar (they are already awesome with 180 HP).

Normal cruise speeds at 8K are north of 160KTAS with ~ 7.5 GPH, 50°LOP.

Break-in was a non-event, running 75% or above until the cylinder temps and oil consumption stabilized. About 8 hours for cylinders and 20 for oil.
Today, on average the engine burns about 1 quart/15 hours.

What would I change if I needed another engine?
Probably "normal" compression pistons to eliminate the 100LL only restriction.
I'm not tempted to test MOGAS before further, indepth considerations or even know if it's reasonable to consider.
The extra horses are always fun to have but are they a must??

I'm very happy with my engine and prop choices.
ASP and its staff are awesome.
I could'nt attend the build school in spring of 2020 because of COVID.
I may attend a future build of a similar engine, for education and personal interest.
 

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The 370 with 9.6cr is conservatively rated 195HP, probably closer to 205.
ASP uses the continental 370 components; I went with Continental build myself and couldn't be happier.
Oil consumption like others in around qt/8hrs but love the extra ponies!
 
20 HP

According to the engine data plate, it's rated at 200 HP, at least with 9.0:1 pistons.
If I recall, (ASP's site doesn't mention it anymore) with lower compression pistons it was rated at 195 HP.
 

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HP rating

At the time I bought my low compression IO-375 in 2010, the HP number quoted was 195. I don't believe it was based on Dyno testing (at least at that time) but rather extrapolation. Based on later Titan (Continental) data, it is realistically more like 185-187 HP. The lower numbers are much more consistent with my observed performance numbers.

Answering the original poster's question about tapered cylinders - as far as I know, the "experimental" cylinders from ECI (now Continental) are the only ones with tapered fins. Lycoming, Superior Millenium cylinders and "certified" Continental cylinders are all straight fin.
 
Bought mine in 2021, installed earlier this year and currently have ~170 hours on it. Same experience as others. If you get the straight fin cylinders then the baffle kit will bolt right up. If you get the same carb,mechanical injection, or ignitions that Vans offers, then it will all bolt up right up. The exterior dimensions of the 360 are the same as the 375. It's when you start going with EFII or SDS with aftermarket sumps and other options that it starts taking more effort.

Mine was optioned as a 9.0:1 pistons w/ squirters, port/polished heads on tapered cylinders, with superior sump and SDS ignition/injection, and the counter-weighted crank. I believe they ship the 9.0:1 and 9.5:1 compression engines only with the counter-weighted crank now. Data plate shows 195hp, it climbs at 1500-2000 fpm at full gross and cruises at 165 true on ~7.5 gph LOP. If I go ROP, it cruises >175 on 11gph. I have to go way ROP to keep the temps under control, but that's a cowling issue, not an engine issue. I looked into the MT 3-blade as well and was told you NEED to use the MTV-9 and not the MTV-12 because of the higher torque pulses. This means the MTV-9 is 56 lbs installed, which was too much for me. I went with the Whirlwind 300 which is approved for the 375 w/ counterweighted crank and only weighs 36 lbs. I see between 5 and 8 hours per quart of oil, which is a lot of oil compared to a standard 360, but seems to be "normal" for the 375.
 
15 more cubic inches NOT 15 more HP. Probably half that

I can only go on the information provided by the manufacturer, that’s why I’m here for further reports from current owners. The info I received states 375 cubic inches and supposedly 195 hp.

Thanks everyone for the information so far. I’ve searched for and read all the posts on the IO-375 and have received a lot of good stuff from you all today.
 
As far as I understand, ASP does not dyno the individual engines.
If they're equipped maybe they can if asked/required??
I know mine was not as it was hooked up to a carburator for the 2 hour test bed run.
 
ASP IO-375 with 325hrs. 8.3:1, tapered fins. No serious baffle install issues. Cold air sump and I made my own throttle cable bracket. I burn Swift Fuel 94UL as often as possible. 13 row oil cooler is on RV-10 firewall mount with butterfly valve in duct works extremely well. Oil consumption 10-12 hrs/qt. Vettterman trombone gives great cabin heat. More info below. I’m very happy with it.
 
OI-360 with superior sump, Vetterman crossover, twin EFII ignition, tapered ECI cylinders...

Like was said earlier, the footprint of the 360 is the same as the 375 and all the other mods mentioned are also required for the 360.

If you go with the tapered cylinders, DO YOUR BAFFLE FITTING AROUND THE CYLINDER WHILE IT'S ON THE STAND!! You'll get a better result and spend less time dinking with it later.. just sayin'

I had a visit with Rob (the owner of ASP) this summer and he said that their intent was to move some equipment around the shop and install a Dyno for on site testing. Don't know a date but he is very interested in providing that service.

And yes the people at ASP rock! I'd be happy to work there myself!

Cheers
 
OI

If you go with the tapered cylinders, DO YOUR BAFFLE FITTING AROUND THE CYLINDER WHILE IT'S ON THE STAND!! You'll get a better result and spend less time dinking with it later.. just sayin'

I just added a few holes to the lower tabs on the inner baffles and pulled them up tight, absolutely no CHT issues. This also gives me the option to go back with straight fins if the need ever arises.
 
I’ll post Dyno runs for a few TItan 370s when I get back to the office. The extra in^3, taller pistons, better breathing Superior sump (cold is a bit of a misnomer), EI, etc pushes these to about 210 HP IIRC. This with standard Titan cylinders which are also supposed to breath better; not require porting/polishing.

The representative data is nice but ultimately, the proof is in the actual performance.

I have no loyalty to Conti or Titan but JB Ball is one of the best guys in the business. He saved me a bunch of money.
 
Not flying yet, but installed.
The Build School was wonderful. Highly recommended. I posted about it.
Installation has been effortless. The only difference is the crank, so externally it's another IO-360 depending on starters, alternators, sumps, etc. I can't wait to add my flying experience with it.
 
i have the low compression io375 with a cold air sump and nickel cylinders. installation of baffles and control cables is a bit different than standard 360 but not more difficult.

my oil consumption is at around 8 hours/quart and this (surprisingly) seems to be the norm with that engine.

i have no idea if it's makes the 195 hp stated on the engine placard. and honestly... i really don't care how much hp. i figured that an RV7 with any 360 is well hung so to say. :D

i'm happy with the engine.
 
Titan taper fin cylinder support

Continental has published a new service information letter (SIL005) that addresses aftermarket availability and support for the taper fin cylinders.
It's new and it will take a while for the parts to be set up and stocked at Continental's master distributor, Boeing, and others. I thought that the group would be gratified to know that cylinder availability is in the works.

It's found under the home page Support tab, then Service Publications, then Service publications for experimental engines.

http://www.continental.aero/titan/documentation.aspx

J.B.
 
Baffling?

I am now trying to install the standard Van's Baffle kit on my IO-375 M1S, and on initial glance, it does not seem simply compatible. On the two sides of the baffles which mount to the cylinder heads, the bolt holes do not match the holes I find on my heads.
The Baffle kit is expecting two bold holes which are in line and above the center of the cylinder. My cylinders have one hole in that place, but another hole diagonally across the cylinder and below the center.
Are my cylinders different? Is my baffle kit different? Or, is this, in fact only a slight alteration I should not be concerned about?
 
I am now trying to install the standard Van's Baffle kit on my IO-375 M1S, and on initial glance, it does not seem simply compatible. On the two sides of the baffles which mount to the cylinder heads, the bolt holes do not match the holes I find on my heads.
The Baffle kit is expecting two bold holes which are in line and above the center of the cylinder. My cylinders have one hole in that place, but another hole diagonally across the cylinder and below the center.
Are my cylinders different? Is my baffle kit different? Or, is this, in fact only a slight alteration I should not be concerned about?

I’m guessing you have a parallel valve engine and an angle valve baffle kit.
.
 
D'oh!

I knew the ordering at Van's was a bit convoluted. I knew it, and I got it wrong anyway. Yes, the IO-375 is a parallel valve engine, but in order to get the correct baffle kit from Van's, I needed to order the O-360 baffle kit.

New baffle kit ordered. Now I get to do the reverse inventory to make sure I'm returning everything, and wait for the FedEx man.

It sucks to be human.
 
Clay,
I installed the IO-360 parallel valve baffle kit and it was not a big fuss.
Just don't trim down the left/front ramp inlet before you fit the snorkel. Leave it as long as possible. It's easy to trim too much off.
 
Yes . . . .

. . . . assuming you are talking about the parallel valve IO-360 (180 HP) and not the angle valve IO-360 (200 HP). Pistons will vary depending upon which compression ratio -375 you get.
 
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