Is it worth the trouble?? throttle bodies

by itself (espcially w/ the sandwich style adapter plate setup which SUCKS) an oversize t/b might make the throttle response a bit better, but not much in the way of power gains...however, combine it with a match ported intake manifold opened up to the correct size (drill or dremel with a flexshaft and an asst of grinding stones works quite well, pick up a junkyard manifold or two and do it yourself) can make something like 8-10hp depending on other mods and the condition of your engine...you will definitely need to have your CO and idle reset after the install, but there's almost no downside- my car pulls much harder from idle to redline, revs faster and smoother, and seems to get a few more mpg on the highway..w/ the g grind and some headwork, it used to make power to about 6200-6500rpm then it was choking, now I have to keep an eye on the tach cos' it just keeps making power, at least to 7k, I don't push it past that if I can help it (i do have h/d valve springs to keep everything in check) if you junkyard everything, it's a great gain for few $$, good luck

Re: (fat biker)


call me another sceptic.
The bigger throttle body and ported manifold on my bunny make it feel faster because it has snappier throttle response but I seriously doubt there's any real power gain. At higher rpm a big 1.8 or 2.0 engine might gain a little bit but I wouldn't expect 10 or even 5 horsepower.
I wish I had a dyno...I'd test it and let you know!
jamie

maybe I need one of the tornado thingys for my intake...you know "turbocharge any car"...surely a plastic beanie prop stuck in my intake tubing is good for like.....50 hp? guess I'll need a 6ft high 2 level carbon fiber wing to add some downforce too, and soo stylish now if I can only get these 24's to fit my rabbit hehehe (sorry I was feelin silly)

Re: (joeymigraine)

I've done it. I might have felt a little bit but more likely than not it was trying to justify the 10 buck upgrade. If you get 10 hp for the throttle body, 15 for a port job, 10 for a g-grind, 10 for twintube manifold and downtube, and 10 for a 2" exhaust, 15 for 2.5" exhaust then your car is faster than anything. That intake and throttle body are not that restrictive even with a better exhaust.
Techtonics used to sell a GTI 15 hp kit which was a g-grind cam, better exhaust and an adjustable cam. Techtonics claims are more real than many of these newsgroup claims. Now they have an A3 kit that does about 20 hp.
If you really want to see if it make a difference let someone else install the old one or the new one and let you take it for a drive. Let him put something els on or not. Do this a number of times and see if it really makes a difference. It is called blind testing where the driver has no knowledge of what has really been done. Or just take it to a chassis dyno for a few runs and $50.
Change a throttle body has no effect on mixture. No need to screw around with mixture screws. The mixture is affected by the flow of air and it measures that flow of air. If your throttle body flows more air it would compensate for that.

Changing the throttle body alone wouldnt require CO adjustment, but (at least in my case) it did need to be richened slightly after the bored out intake manifold was added.....i suppose it could have been out of adjustment prior to that, but I dont believe so......as I said I would imagine it was a cumulative effect of just the right combo of cam, head porting, intake porting, throttle body, and exhaust manifold and exhaust.... I had it dyno'd on the dynojet at EIP a few years ago,before the headwork and the manifold (just the G cam, airbox swiss cheesed on the side away from the engine, dual outlet US manifold, TT 2" exhaust (gutted cat) and neuspeed t/b (then I was using the stupid sandwich plate, I didnt know any better at the time) and at that time it made 98.1whp and 99.9 ft lbs 1st run and 96.6 whp and 101.4 ft lbs on run the 2nd run, this on a 97.3 degree day....I am pretty sure that the port/polish work and port matching on the intake/t-b/head/ added between 10-20 whp possibly more, bringing me to approx 110 whp, so maybe 125 flywheel? maybe I'll have to do some dyno runs soon, cash flow permitting.. anyway I wasn't trying to start an issue over real/percieved HP just give my impressions/experience with the ported mani/tb per the original question ...does anyone have some before/after dyno numbers for this they can post perhaps?

Re: (joeymigraine)

My CAI and cat back picked up 20hp j/k