In an old thread, http://stunthanger.com/smf/index.php/topic,7992.0.html of 7 years ago describes available CL conversion parts for Thunder Tiger .25GP R/C engine.

That was a while back. I've got an NOS .25GP R/C. Does anyone know where I can get a venturi and NVA for it?

Perhaps I should clarify. This is the old plain bearing .25GP made in the 1990's, not the more recent GP-25. I don't know how similar or dissimilar these two are.

The engine I have is the earlier Magnum .25GP by TT. Width across pinch bolt is 13mm. Engine looks similar in appearance to yours, I don't know the differences if there are any.

George, I measured the boss on mine and measured 13.5mm (~17/32"). A GP 40 was the same.

The pinch bolt is 4mm, so the hole is a good fit for an ST NVA. I used ST 46 NVAs on some of mine but to centre the hole in the boss required brass washers both sides.

I measured a Brodak 40 NVA and I believe that it is ideal—if/when you can get them.

Here's a TT25 PRO with a conversion set froM Bill Bischoff. It's meant for the Magnum 15 for racing, but works well on this engine for stunt.

Here's a TT25 PRO with a conversion set froM Bill Bischoff. It's meant for the Magnum 15 for racing, but works well on this engine for stunt.

Hmmm, mine is different. Same engine but the Supertigre spraybar goes through the hole where the retaining bolt is on yours and feeds a 3 hole sprinkler venturi a lot like a Tee Dee. Mine needs choking down. I wonder if I could JB weld a ring of short brass tube in the venturi to neck it down a bit. Maybe someone has tried that and can tell me if it's a reasonable idea.
Rusty

The venturi in my TT GP25 with the ST-style NVA through the pinch bolt hole is 0.136".

With no spreay bar restricting the venturi throat, you need to forget all your 'conventional wisdom' on venturi ID.

Got a NEW T T Venturie the other day . Teeny Hole . UNFORTUNATELY I needed TWO ! SIX WEEKS WAIT ?? WHATINTHEFK .

Anyway , have the ' part no , PN1081”

' the ' deck hight ' is larger than the MaGNUM ! SO NEEDS A SPACER .
The MVVS D7 , ST C 35 & Magnum 25 *& 40 match . The TT 25 is about 1/8 plus at the O ring , as it were .But Diameter matches . For my GP 25 Magnums .

or to clear the mud , the TT intake fitted to a Magnum etc requires a slice of rubber tube , 1 / 8 in odd , as an O ring . so I figure .