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kirkbauer

Active Member
I'm debating between a normal IO-540, a Thunderbolt IO-540, or a third-party engine source. I did a lot of searching here on VAF but my ignorance of engines is not helping me out. I'm hoping some people can help me interpret some of the options on the Van's Thunderbolt order page (https://www.vansaircraft.com/order-a-kit/lycoming-thunderbolt-engines-order-form/). I'm looking for dual pMags but am not looking to complicate my build or require significant alterations.

1) It looks like if I order this engine I get an Airflow Performance fuel system -- do I want that? What does the normal IO-540 come with? How do both of these compare to Silverhawk? They have a note on the order page
  • Note: When ordering the IO-540 with an Airflow Performance throttle body, you will need to provide some components that are not included in our Firewall-Forward kit. Specifically, the push-pull cables, VA-182 throttle/mixture bracket and fuel hoses will likely need to be replaced with parts that fit the AFP option, and the Van's filtered air box may require some modification .
2) The order page says "requires Slick-Start booster system". What does that mean and why don't I need it for the normal IO-540?

3) I read that the Cold Air Induction option requires cowling modifications. How much power do I gain from this expensive ($5,700) upgrade and how extensive are the modifications required?
 
If your top priorities are “not looking to complicate my build or require significant alterations”, then you need to weigh the Cold Air Sump option.

Modifying the stock Van’s cowl is possible, but not for the faint of heart. Two vendors offer RV-10 cowls for the Cold Air Sump IO-540, Showplanes and James Aircraft. I have the James version in the hangar (along with a new Thunderbolt Cold Air Sump IO-540). The tumbrule is this is a ~15hp bump over the vertical induction IO-540.

Some other thoughts:
- Compression ratio. Thunderbolt offers 9.0 pistons if you want (I think this is a~$3K up charge but you should check). I stayed with stock 8.5 pistons as I want the option to burn 93 ethanal free mogas - but many people opt for 9.0 pistons.
- The first build was a stock vertical induction Lycoming IO-540 with Slick Mags (no Slick start booster). The six cylinder pMag was not yet available. I was careful to only start on the left mag as it had a timing retard breaker. Never a problem starting.
- The new engine will have dual pMags (so the Slick booster is not applicable as the pMags have retarded timing during start). I’ve been running dual pMags on all the other builds.
- I consider the AFP option a no brainer and recommend it. The needed control cable brackets are available from Don at AFP (and just bolt on).
- I suspect most third party engine builders can offer the same options as Thunderbolt, so shop around.

Carl
 
If you are a hands on person, I would recommend Aerosport. I got my IO375 from them, dual pmags, inverted oil, but best of all, I got to travel there and build it myself with their oversight. Fantastic experience and I know my engine inside and out, literally.
 
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