Weber carb comparison, Stock /6 IDTP vs. 40 IDA Options

[Lavanaut]

I'm wondering what the differences are, and in general (flame suit on) which is "better"? More specifically, what would be the benefits/drawbacks in changing from IDTP-->IDAs? For what it's worth, this isn't something I'm considering doing, it's something that's already been done on a factory /6 I'm looking at. I have the opportunity to purchase the IDTPs in addition to or as a replacement for the IDAs, but have been told the engine is running very, very well with the IDAs. I like the originality idea of sticking with the stock carbs, but don't want to sacrifice performance or the convenience of a more modern, more fully developed product *if* that's what the IDAs constititute.

Basically I don't know shit about carbs. Yet. (IMG:style_emoticons/default/smile.gif) Any and all feedback (opinions even!) would be appreciated.

Thanks all

(IMG:style_emoticons/default/chowtime.gif)

edit: Replaced "40s" verbiage with "IDFs" in an attempt at clarity
re-edit: Replaced "IDF" verbiage with "IDA", since that's what they actually are

[SirAndy]

Any and all feedback (opinions even!) would be appreciated.

Carbs suck! (IMG:style_emoticons/default/stirthepot.gif)

[Lavanaut]

(IMG:style_emoticons/default/av-943.gif)

[sixnotfour]

if its a six, its either IDTP or IDA or IDS

IDTP's have a step on the mixture screw.

[Lavanaut]

Yes, they're IDTPs. I wasn't positive if it was IDTP or just TP. Thanks for clarifying.

[SLITS]

Well, Foist .... I do not know nor never have heard of a triple throat IDF.

911 engines (including 914/6) were equipped with Weber 40 IDA 3Cs, 40 IDAP 3Cs, 40 IDS 3Cs and 40 IDT 3Cs. This is not to mention the Solexs and Zeniths.

And I don't know the differences between IDA / IDAP / IDS / IDT.

From the information I have at hand, they are all the same.

AND .... carbatooters for a street engine really SUCK; I am a dyed in the wool FI man. If I want to hear the engine suckin' air, I take the airbox cover/filter off. (IMG:style_emoticons/default/biggrin.gif)

Damnit Jeff

[Lavanaut]

Well, Foist .... I do not know nor never have heard of a triple throat IDF.

That's good to know, thanks Ron. I'll check back with the seller.

AND .... carbatooters for a street engine really SUCK; I am a dyed in the wool FI man. If I want to hear the engine suckin' air, I take the airbox cover/filter off. (IMG:style_emoticons/default/biggrin.gif)

I'm not necessarily pro-carb or anything here fellas, it's just that WOW, finding a stock injected factory Six is TOUGH! (IMG:style_emoticons/default/shades.gif)

[sixnotfour]

slits do you want the rod ?

[SLITS]

slits do you want the rod ?

A 5 cylinder 3.0 may leak a tad bit of oil. Just got your message and I will get back to you in short order.

[SLITS]

Well, Foist .... I do not know nor never have heard of a triple throat IDF.

That's good to know, thanks Ron. I'll check back with the seller.

AND .... carbatooters for a street engine really SUCK; I am a dyed in the wool FI man. If I want to hear the engine suckin' air, I take the airbox cover/filter off. (IMG:style_emoticons/default/biggrin.gif)

I'm not necessarily pro-carb or anything here fellas, it's just that WOW, finding a stock injected factory Six is TOUGH! (IMG:style_emoticons/default/shades.gif)

No such thing ... but ... a conversion does. You take the carbatooter 12-17 mpg; I'll take the 22 - 27 mpg with FI. (IMG:style_emoticons/default/flag.gif)

[Lavanaut]

Well, Foist .... I do not know nor never have heard of a triple throat IDF.

911 engines (including 914/6) were equipped with Weber 40 IDA 3Cs, 40 IDAP 3Cs, 40 IDS 3Cs and 40 IDT 3Cs. This is not to mention the Solexs and Zeniths.

Ron, you were correct, the carbs on the car I'm looking at are 40 IDA 3Cs. I've changed the topic title to reflect that fact.

Now...anyone out there able to compare the two for me at all...?

Thanks

ps: Hey sixnotfour, if you're gonna give Slits the rod please do so in private... (IMG:style_emoticons/default/wink.gif)

[6freak]

Well, Foist .... I do not know nor never have heard of a triple throat IDF.

911 engines (including 914/6) were equipped with Weber 40 IDA 3Cs, 40 IDAP 3Cs, 40 IDS 3Cs and 40 IDT 3Cs. This is not to mention the Solexs and Zeniths.

Ron, you were correct, the carbs on the car I'm looking at are 40 IDA 3Cs. I've changed the topic title to reflect that fact.

Now...anyone out there able to compare the two for me at all...?

Thanks

ps: Hey sixnotfour, if you're gonna give Slits the rod please do so in private... (IMG:style_emoticons/default/wink.gif)

WEBERS RULE IF TUNED PROPER ....we need a screw driver happy face

[sixnotfour]

not giving , he's buyin.

IDTP's have a step on the mixture screw.

IDA's wider range of idle mixture adjustment. (no step, full taper)


since your looking for #'s matching you might as well have the correct carbs on hand.

[Lavanaut]

IDTP's have a step on the mixture screw.

IDA's wider range of idle mixture adjustment. (no step, full taper)

Cool thanks. Can you translate that for me a little bit? Meaning, given those facts, how does that affect tune-ability, performance, ease of use, etc, when comparing the two?

[sixnotfour]

Depends on the motor build , stock no difference.
ask why he changed em ?

[brant]

factory 6's were all carbed
the difference would be the number on the outside of the carb are just not right for a number matching car

I wouldn't think there would be any difference in performance
and even the numbers not matching should really produce no difference either
I suppose in a full pro concours maybe....

but for practical purposes... no difference

I don't know the minute differences between the T and A

I do know the IDS carbs had an auxillary enrichment circuit for high rpm
they only made that carb for 2 years (and none on 914's obviously)
even that is a minute difference, but one could argue it is a performance difference at least.

from a realistic view:
my guess is that the original T carbs were getting worn out, and since they cost 1k to have rebuilt propperly, it was cheaper for the owner at that point to put on a set of IDA's than to rebuild them.. its the throttle shafts that wear and no rebuild/self kit addresses that issue. your choices are between 800-1400 to have it professionally addressed.

brant

[Lavanaut]

Depends on the motor build , stock no difference.
ask why he changed em ?

Hmm ok. As for the motor, from my understanding it was very recently rebuilt to stock specs but "L" pistons were used. The seller is not the person responsible for the swap-out, but when I asked him, he commented that in general the IDTPs were somewhat of a step down from the IDAs. For what it's worth the seller is a 911 guy, so that may be no more than his opinion.

Actually, here's pretty much what I know about the motor at this point, "The original motor was rebuilt by Gary Dielacher of GD Racing in San Bruno, CA and has less than 5,000 on it. The PO told me that they used early '67/'68 911 2.0L pistons which have a higher compression than the stock T pistons"

I guess it need not be a secret, this is the car I'm looking at... (IMG:style_emoticons/default/smile.gif)

[Lavanaut]

factory 6's were all carbed

I actually do know this, my earlier comment was intended as sly humor..but obviously didn't work too well. Should know better.

The rest of your info is good to know, thanks. What would a good set of IDTP carbs go for do you think? I'd assume they'd need to be rebuilt.

[Lavanaut]

Actually Brant, to comment further ~ that's exactly what I wanted to know. "no performance difference". I'm just trying to decide if I should opt to have the IDTPs rebuilt and put those on the car, or leave the IDAs. I'm aware of the desirability of these cars when fully stock, but that's another topic.

Thanks again

[Lavanaut]

I ended up passing on the car. Thanks though for the feedback all. Oh yes, and for the opinions as well. (IMG:style_emoticons/default/smile.gif)