ITB'S and 438,s anyone done this yet

[domsclio182]

As above would be nice to see a graph of this set up.

 

[Meek_racing]

I could be wrong but reading through recent posts, these are the same profile as 421's? Being that these are fairly new I'd doubt anyone has fitted them, if they are the same as 421's then there will be plenty on here that have had the combo done

 

[domsclio182]

I think there are a couple of people who have just interested to see a dyno graph of 438s seen plenty of graphs of 421's want to see if there is any noticeable differences when comparing the two

 

[Dan519]

I could be wrong but reading through recent posts, these are the same profile as 421's? Being that these are fairly new I'd doubt anyone has fitted them, if they are the same as 421's then there will be plenty on here that have had the combo done

they are SIMILAR but not the same. Few subtle changes other than just the timing that dont show on the published data.

They're in testing with ITB's currently I believe, but as said they should be very similar as the changes made were to improve idle and prevent stalling

 

[Chip-mk1]

they are SIMILAR but not the same. Few subtle changes other than just the timing that dont show on the published data.

Well given that the published data includes duration at multiple lift points, and the overal lift and so gives a very good indication of lobe shape they sure must be VERY subtle differences if anything at all, or more likely they're just being a bit vague and hinting there are other changes that arent there as its not good for marketting to say its just an old cam retimed, as although I personally would see the value in that, a lot of people wouldnt. Or maybe they just have a different colour box now, lol

I noticed ktec using a graph for advertising the 438s that they previously used exactly the same graph for advertising 421s as well, so they must also feel that the differences are so slight they wont effect the results at all, well either that or they are misleading people which im sure they wouldnt do

 

[shiftspark]

I thought ktec used catcam timing tools to set up 421 and 428 which altered the exhaust timing from standard if that's the case there must be a difference in the 438's unless it's so they can be fitted elsewhere with the standard Renault timing tool?

 

[Cub.]

Mine will have had both hopefully by March. So, i'll update with relevant graphs then.

I would be interested if anyone has done this to date.

 

[Jonny1*2]

The timing tool ktec have is the one catcam recommend for their cams. Inlet or exhaust is slightly advanced iirc. Can't remember which. It's like grp N timing tool

 

[BIGASH]

Mine will have had both hopefully by March. So, i'll update with relevant graphs then.

I would be interested if anyone has done this to date.

What ITB's are you going for out of interest?

 

[shiftspark]

Lift and duration are the same on 421s and 438's Colin. Timing position differs.

That's what everyone assumes apart from 519and ktec who know, there's a thread somewhere which has a picture of the timing tool if it's just timed different on the blanks why bother if there's a tool to set them up in the 1st place unless it's so they can be fitted by anyone who doesn't have it (£300 iirc)

 

[Jonny1*2]

I think they work slightly better on the catcam tool. It's a bit of a con really. If you make cams for a car it should be made to suit oe timing IMO.
438's are too secretive. I mean why bother. 421's are just as good. What are they hiding. If they were miles better I would understand

 

[Dan519]

The timing tool ktec have is the one catcam recommend for their cams. Inlet or exhaust is slightly advanced iirc. Can't remember which. It's like grp N timing tool

it's nothing like a group N tool, it's a fully adjustable tool which allows you to dial in the cams with the rocker cover removed

 

[Dan519]

I think they work slightly better on the catcam tool. It's a bit of a con really. If you make cams for a car it should be made to suit oe timing IMO.
438's are too secretive. I mean why bother. 421's are just as good. What are they hiding. If they were miles better I would understand

they ARE made to suit OE timint THAT'S THE WHOLE POINT!!!!! 421's you need to f**k about, 438s go straight in

 

[Chip-mk1]

it's nothing like a group N tool, it's a fully adjustable tool which allows you to dial in the cams with the rocker cover removed

You mean its nothing like the cheapy copy group n tools, I would think its very like the actual tool the rally guys were using

 

[Dan519]

 

[Chip-mk1]

Proper bit of kit

 

[Jonny1*2]

they ARE made to suit OE timint THAT'S THE WHOLE POINT!!!!! 421's you need to f**k about, 438s go straight in

I was under the impression that with 421's if you tweek the exhaust cam slightly one way, they run better. I assumed the catcam tool did this. Not to say they don't run with standard timing as mine runs fine, and will run even better when I get the idle raised.

View attachment 69579

This doesn't look like it would twist :approve:

 

[shiftspark]

I don't know why everyone's getting hot under the collar over these , even if the cam lob timing is the only difference,if they get the same results as 421's without having a higher tick over or lumpy idle then alls good to me!!

I will let you fit them to mine if anyone needs more proof ( foc though) lol

 

[Jonny1*2]

I don't know why everyone's getting hot under the collar over these , even if the cam lob timing is the only difference,if they get the same results as 421's without having a higher tick over or lumpy idle then alls good to me!!

I will let you fit them to mine if anyone needs more proof ( foc though) lol

Exactly mate.