What's holding back?

Hey guys (and gals), I'm fairly experienced with engines in general, but I can't really figure what's keeping my tomos from doing all it can. I got the biturbo and that helped bunches, but I feel that there has to be something major keeping this thing from really screamin.

Just revin' it on the stand tells me something; it takes way to long to reach max rpm, and then again, max rpm doesn't seem all that high. Not that I care to run my engine at anything over 4500 or 5000 rpm, but it still seems something's boggin it down. I have a stock #53 jet in the carb and if i had a spare, i'd dare to drill that sucker out just a hair to see if that would help. But, in the meantime, i'll let common sense slow me down til i get some real suggestions. Any ideas, folks?

Eternally seeking power,


Re: What's holding back?

Chris Robertson /

Hi Lane:

There are three major factors that affect your engine tuning. Usually everything has to be increased together (with a whole bunch of variables and "what-ifs").

Think empirically about the three things the engine needs:

1. Fuel (jet size)

2. Air (carburetor diameter, air filter)

3. Exhaust Flow (bi-turbo, port size, port angle, exhaust diameter)

You've increased the exhaust flow, now you have to make sure your engine is getting enough air and fuel to keep up with it. One of those three things is always your bottleneck.

Also remember that the harder you tune/drive your engine, the faster parts will wear out.

I'll admit I do not have experience with bi-turbos so maybe somebody else can give you more specific information.


Re: What's holding back?


I have more questions for you than answers. How do you measure the rpm

Re: What's holding back?

I got really pissed today cuz i had to ride my ped up a really steep long hill. I had to scoot along with my feet a few times...downfall of getting a ped without pedals. I think I'll try the smaller sprocket up front before I screw with the engine anymore. Things are already rattling more than I think they should for an engine with only 650 miles on it. Anyways, I'll run it til it quits and then build it back better.

I don't work in a VW shop, but i have tons of experience with them. The only VW related thing I own at the moment is a rail buggy with a 1600cc engine. Man, it's a blast. I've never worked on a karmen ghia (as you could probly tell by my spelling of it) but i'm sure lotsa mechanical parts are the same as beetles and such. If you got any specific questions, fire back at me and I'll get ya my email addy...

Get it when ya can,


Re: What's holding back?

Reeperette /

>>Why would you ever bother drilling out a jet?! They can

Re: What's holding back?

gimmejimmie /


It was....david f martin...that works on VWs that posts here sometimes, search him up.

I had a K. Ghia convertible years ago, dark green w/ white racing stripe and white rag top, loved it, wished I had it today, I'd put a Porche engine in it if I did. There are websites dedicated to Ghias with pics and parts, gotta search for them too.

You will enjoy that collector car, have fun with it.

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