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Discussion Starter #1
Iv been building a small block valver for 10 months now as budget allows
so far it has;
Ported gas flowed head with 3 angle valve seats
JE pistons with 11.5:1 CR as well as taking the CC close to 1700
Lightened and balanced flywheel and crank

Future buys are;
TBs
Emerald ECU
Newman cams, approx 260 degree not sure what lift yet
Vernier pullies
I intend to start off at 1/4mile sprints and track days,
but eventually get into hill climbing

so my question is, what is the criteria for chosing TB size?

Iv resulted to taking my inlet valve size into consideration;
36mm, with 2 that would give an area of 2035.752mm
and an overall diameter of 50.911688mm

so in theory anything up to 51mm would be good
but some people have told me 40s would be best for my kind of driving(week end use included)
and others have said to go for 45s....
Is there that much difference between the two??

TIA
 

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45's will give you a higher up peak power which will be a higher fugure, the 40's may give you 5 bhp less but will have more torque through the range, especially lo down. I'ld go for 40's personally.
 

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if you can afford it go for 45's, A well modded 1600 runs better on these i've heard.

You'd be better off running 34mm chokes in a pair of 45's than in a pair of 40's.
 

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Discussion Starter #6
yes it is a 16v engine

when i say 40s or 45s, i mean Jenvey throttle bodys, not carbs sorry.
Last time i looked on the Jenvey site the two were the same price.
So its conflicting views on here also?
 

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i do cracking stuff for the x14xe. what rods you running? for the love of god dont run standard ones modified to take the JEs
and dont run standard crank if going over 8k they tend to 'wander' lmao
 

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Discussion Starter #9 (Edited)
lol, to be completely honest it isnt an XE, its a volkswagen
Im using an older style 1400 block with GTi 1600 rods and crank.
Sent the OE 1600 piston and rod complete to JE, its an exact copy
bar the 2mm overbore to get it near 1700cc.
Was also going to use ARP bolts and an absolute maximum of 8k rpm

So what you think Rob, is the 40/45 decission that
important to the performance of the engine??
 

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thats ok i do stuff for those too :D lmao
45s, so common its pointless to go for anything else, its not like carbs where you need to worry about choke sizes etc, you simply fuel for the air you have
 

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Discussion Starter #11
45s it is then! lol
what stuff do you do for these then, got a price for ARP rod bolts?
cheers
 

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Discussion Starter #13
Block is AFH, so thats the cam setup
Internals are AUS, for the rods
cheers Rob, was wondering what happened to the 16vastra user name
all is explained :cool:
 

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yeah thought i had a good cam for that one :p
bolts are weird, as usual the air cooled stuff gets the most coverage, the rods arent the same as the g60 are they?
 

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Discussion Starter #15
no, totally ifferent, as its a much newer design, and not a big block engine
got my engine shop block looking into it anyway
 
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