Intercoolers? Merlyn Auto Wastegates?
Question:
I’m trying to get some feedback on the relative merits of these modifications to my Seneca II. I’ve just purchased the plane, and am having a fair bit of work done at this time, and I’m wondering whether these are worthwhile? Also, how much are they? Engines are TSIO 360’s by the way…fixed wastegates. Thanks for the feedback! Brad
Response:
I’m trying to get some feedback on the relative merits of these modifications to my Seneca II. I’ve just purchased the plane, and am having a fair bit of work done at this time, and I’m wondering whether these are worthwhile?
I fly a turbo Arrow III, TSIO-360-FB. For me the Merlyn wastegate was definitely worth the money. o Reduced temperatures down low (our typical field elevation is around 700 feet. o Increased turbo and engine life accordingly (less work and heat) o Increased service ceiling by more than 5000 feet (with upper altitude climb increased accordingly). o Less sensitive to throttle movement I found the Merlyn folks to be extremely good to work with. Very helpful, very concerned with product satisfaction. There is one thing that the Merlyn wastegate is not, and does not claim to be – it is NOT turbonormalization. You still don’t slam the throttle to the firewall and go. But you are a lot less likely to overboost with the Merlyn. Now, last issue: Intercoolers. A good intercooler can be a big help, but is it worth the cost? In my case, no. I don’t have any real temperature problems, even up in the flight levels. I know another guy a few spaces down from me with the exact same plane and Merlyn *and* intercooler — he doesn’t have any temperature problems either! But the Seneca may have different cooling issues. I’d check some back issues of Aviation Consumer and maybe Light Plane Maintenance for any history of Seneca cooling problems. Maybe talk to the Merlyn folks also. If not a big deal, then I would skip the intercooler, buy two sets of GAMIjectors, and have money left. [The GAMIjectors are **highly** recommended.] jmk
Response:
What are your experiences running GAMIs on the TSIO360? I have a Mooney 231 and am interested in how GAMIs impact an engine with Merlyn and your methodology for operating it (I also have an Airflow Systems intercooler). Thanks! Ray – Hide quoted text — Show quoted text – [The GAMIjectors are **highly** recommended.] jmk
Response:
- Hide quoted text — Show quoted text – Now, last issue: Intercoolers. A good intercooler can be a big help, but is it worth the cost? In my case, no. I don’t have any real temperature problems, even up in the flight levels. I know another guy a few spaces down from me with the exact same plane and Merlyn *and* intercooler — he doesn’t have any temperature problems either! But the Seneca may have different cooling issues. I’d check some back issues of Aviation Consumer and maybe Light Plane Maintenance for any history of Seneca cooling problems. Maybe talk to the Merlyn folks also. If not a big deal, then I would skip the intercooler, buy two sets of GAMIjectors, and have money left.
Intercoolers do a lot more than address cooling problems. They provide higher safety margins as far as potential detonation problems go, and they increase power output significantly. After I intercooled my Aerostar the cruise speed increased by 15 knots at altitude. Marc Rodstein
Response:
What are your experiences running GAMIs on the TSIO360? I have a Mooney 231 and am interested in how GAMIs impact an engine with Merlyn and your methodology for operating it
I am very fond of my GAMI set. Very good example: I have had to make three trips from Austin to St. Louis and back in the last 6 weeks. No wind, that should be about 4 hours each way — no problem. **But** last trip I managed to have a major headwind (and I mean major — 62 knots just off the nose on the way up) **both** directions (as in another 40 knots on the nose on the way back south two days later! {:<( Why don’t the gods like me? The trip time at virtually any altitude was right at 5+15, almost regardless of altitude (higher I plan for the faster I go, but the headwinds increase by the same amount). And you can virtually guarantee a big vector/detour at St. Louis. Normal POH shows only 5 hours endurance, 6 hours if I lean out to peak and run the EGT/CHT’s right up to the limit. And I would still be hitting St. Louis class B with fumes in the tanks. So I took off, climbed to about 12,000 (best wind/speed combo – and not very good at that!) and leveled in cruise. Set the prop up for 2200 RPM, pulled the mixture quickly back to *well* lean of peak (LOP). Then pressed the LEAN-FIND button on my JPI EDM-700. I **enrichened** until it showed the first cylinder to peak, then **leaned** back out until I was about 70 degrees LOP. [All of this is no harder than normal leaning procedure - just backwards!] Last, I pushed the throttle forward until I had my normal cruise airspeed or a little more and watched the EGT/CHT temps. Net result – cruising at normal or greater speeds with all temps showing more than 100 degrees below redline, and a little above 10 gph. Arrived from the southwest to St. Louis, got vectored another 50 miles out of my way (to land on that short little 2000+ foot runway that runs between the buildings at Lambert), and still had slightly over an hour in my tanks. So yeah, I like them. One note: I don’t recall exactly, but there is one particular model Mooney for which the fuel system is set up much better than the average TSIO-360. On that one the benefits are not anywhere near what they are typically, and I don’t believe GAMI even sells their system for that model. Check with Tim or George up there and see which it is. Also, run their little test procedure (if you have a full-probe monitor) and you will get a good idea of what kind of fuel savings you will see. jmk
