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crx
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Discussion Starter #1
Guys can anyone recommend a good aftermarket throttle body. I am running a jrsc and had my stube ported and polished by Mr. Grimm, he recommended a bigger one. Although the tube from the throttle body to the charger is still going to choke it somewhat. I plan on getting another one fabricated up in the future.

thanks
 

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crx
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Discussion Starter #3
I was thinking of something bigger, more like 68mm. I could have mine bored out to 60mm.
 

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How much power are you planning on making? Because unless you are making some serious power, like twice what a JSRC is capable of making a D series, I dont much see the point in anything over 60mm.
 

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I have about a 200hp b18c1 crx, biggest upgrade I have done to it is taking off the 70mm TB and putting on a stock B series 60mm TB. Drastically increased my throttle response and gained about 8 MPG, top end was at least as good if not slightly better.
 

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crx
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Discussion Starter #8
thanks' guys for the responses. I'm thinking of taking your advise and getting mine oem bored out. I hear Maxbore does good work. I always read superchargers like the least restriction, so I figured bigger was better.
 

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90 CRX Si
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I think on the JRSC where it's having to pull the air through it you may benefit from a larger TB. I have a Maxbore 64mm (OEM GSR TB opened up) and he did excellent work, and now I have a Skunk2 70mm. It doesn't operate as smoothly as an OEM and tends to stick at about 1% instead of closing completely.
 

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crx
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Discussion Starter #11
I think on the JRSC where it's having to pull the air through it you may benefit from a larger TB. I have a Maxbore 64mm (OEM GSR TB opened up) and he did excellent work, and now I have a Skunk2 70mm. It doesn't operate as smoothly as an OEM and tends to stick at about 1% instead of closing completely.

Good to know, you never know with after market parts sometimes. I would prefer to stay oem. I hear some guys say these work well.

Import Performance Parts - Professional Products Throttle Bodies
 

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Any TB can stick or do wierd things, my OBX 70mm that was on the car when I bought it worked like garbage at first. You take it off clean everything up, lube it up lightly, adjust it so it closes all the way wihout sticking, adjust the TPS sensor and then you are good. I have had to do this with both stock and aftermarket throttlebodies, and anyone who doesnt do this to their 20+ year old throttlebody is missing out.

Even with the 70mm OBX TB functioning perfectly, it still lost out everywhere over the stock 60mm one though. You just loose throttlebody control along with air velocity.

The only reason they seem to make some improvement is because right after you put one on what was 10% feels more aggressive because it is now 15%, what was 20% is now 30%, what was 60% is now 90%, what was 80% is now 100%, but what was 100% is still only 100%. There isnt any real improvement in 99% of cases, only loss of resolution that seems like more power on the surface.
 

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ED6&7. EE4&5, MB1
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The only reason they seem to make some improvement is because right after you put one on what was 10% feels more aggressive because it is now 15%, what was 20% is now 30%, what was 60% is now 90%, what was 80% is now 100%, but what was 100% is still only 100%. There isnt any real improvement in 99% of cases, only loss of resolution that seems like more power on the surface.
I made this back in the days.
 

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94 Integra
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I'd really recommend a 60mm B-series, they're $20-40 on ebay. The next step would be the 68mm Omni, but I haven't seen many D16 JRSC's that could max out the 60mm TB.


I have about a 200hp b18c1 crx, biggest upgrade I have done to it is taking off the 70mm TB and putting on a stock B series 60mm TB. Drastically increased my throttle response and gained about 8 MPG, top end was at least as good if not slightly better.
Have you datalogged your manifold pressure? My H23A-vtec does NOT like the smaller 60mm TB I put on it. After 5300rpm it creates vacuum & dips to -1psi at redline. Virtual Dyno and 1/4 MPH puts it in the 195whp range.

I made this back in the days.
As much as that is appreciated, it obviously doesn't account for the 1/4" rod in the center. The increase is actually slightly non-liner.
 

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90 CRX Si
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Speaking of datalogging, I was seeing pretty serious restrictions on my 11.5:1 B18C1 with Blox intake mani and 60mm. It was falling back to 940mBar by redline, or maybe lower. 64mm Maxbore helped eliminate most of that then now with the 70mm S2 and Ultra intake it may drop to 985mBar.
 

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See above...
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I enjoyed using the 68mm Professional Products TB on my boosted build. Was high quality, priced aggressively, and worked flawlessly.
 

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So for those of you who feel you saw improvements from a larger throttlebody, how much power did you actually gain on the top end? Because a reduction in manifold vacuum does not necessarily mean better performance, nor does it mean anything for driveability or throttle response.
 

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90 CRX Si
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So for those of you who feel you saw improvements from a larger throttlebody, how much power did you actually gain on the top end? Because a reduction in manifold vacuum does not necessarily mean better performance, nor does it mean anything for driveability or throttle response.
No dyno numbers for me, or even track numbers since I never drag race any more. I can say it still had great low-mid range paired with the old cams I had in the motor. It was an obvious restriction though as much as it was dropping off.
 
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