438 vs 421

[Carlv8415]

After having a little but if engine trouble I thinking about rebuilding the top end. I decided to go for some high lift cams. The 2 main ones I have been looking at are as above, It's not massive power gains that I'm after more about better drivability. One thing I don't want is a dodgy idle, correct me if I am wrong but do the 438's offer the same power as the more aggressive 421 but without the rough idle?

I know the 438 cams are about £600 and as I getting the top end done anyways it will be a straight swap for original. Would I need a remap or could I run on standard map?

Thanks

 

[Dan519]

they're almost the same, but 438s are slightly modded for a better idle. They're exactly the same price. My old 172 ran 421s, and when I removed the ITBs I left the cams in and we got it working perfectly. First one on FBW throttle as far as I'm aware.

you will absolutely need it mapping. No way round that

 

[Carlv8415]

438's it is then. Can I run just the cams for a little bit or will it need a remap straight away? Will an RS Tuner map be sufficient ?

 

[Dan519]

you'll be ok to drive it around at light throttle and low revs, but no more than that. You will need it mapping properly

 

[Carlv8415]

you'll be ok to drive it around at light throttle and low revs, but no more than that. You will need it mapping properly

What happens if you start giving it high revs without remap? Out of interest?

 

[Laine_16v]

I wouldnt worry to much, i drove mine unmapped pretty hard for a while with no ill effects.

 

[dmallett]

they're almost the same, but 438s are slightly modded for a better idle. They're exactly the same price. My old 172 ran 421s, and when I removed the ITBs I left the cams in and we got it working perfectly. First one on FBW throttle as far as I'm aware.

you will absolutely need it mapping. No way round that

the car Dan is talking about is this,

 

[Dan519]

right, thats it!! I'm making the 197 sound like that. GOD I miss that car!!!!!

 

[dmallett]

ITG filter

After being in a various cammed cars Id say that between the 421/438 there isnt a great deal of difference imo.

 

[Carlv8415]

the car Dan is talking about is this,

What has been done to that! It sounds amazing ....

 

[Dan519]

I built it = amazeballs engine

 

[dmallett]

Home made induction kit using ITG filter, 421 cams, 182 manifold, gypsy cat, ARP bolts, janspeed stealth exhaust, head work.

Think thats it

I built it = amazeballs engine

Its a decent engine to be fair! Let me know when you want to buy it

 

[Carlv8415]

ITG filter

After being in a various cammed cars Id say that between the 421/438 there isnt a great deal of difference imo.

Yeah I was reading about both and from what people are saying they pretty much the same just the 438 is a better idle apparently

 

[Carlv8415]

Home made induction kit using ITG filter, 421 cams, 182 manifold, gypsy cat, ARP bolts, janspeed stealth exhaust, head work.

Think thats it

Another thing, are ARP bolts really necessary ?

 

[dmallett]

Mine idles fine after about 30seconds, just sits slightly higher to start with then drives fine. Never had issues with it stalling etc like people seem to say.

ARP bolts, imo are worth it for the piece of mind/dealing with the higher rpm. Though my knowledge is limited.

 

[Carlv8415]

Mine idles fine after about 30seconds, just sits slightly higher to start with then drives fine. Never had issues with it stalling etc like people seem to say.

ARP bolts, imo are worth it for the piece of mind/dealing with the higher rpm. Though my knowledge is limited.

Oh right fair enough, just my engine decided to break itself at 7000rpm I think it's something up top that broke (Rocker or spring) so thinking it may need a top end rebuild so might see about cams.

ARP bolts may be a good investment later on. Is it a common thing for the standard bolts to snap ?

 

[Dan519]

the map was specially tweaked to stop it stalling, thats why! lol. If it's not done, then you can cut out approaching junctions and that can be a bit dodgy as you lose brake servo assitance fairly quickly

 

[dmallett]

Well your mapping worked on it Dan!

 

[Fred@BTM]

same cams AFAIK only difference is the exhaust cam is retarded about 5deg

 

[Carlv8415]

same cams AFAIK only difference is the exhaust cam is retarded about 5deg

Lol retarded is it Fred, not rotated by any chance

 

[Cub.]

If you're after a set of 438s, I may be in a position to sell mine in the next couple of weeks. PM me if you're interested.

Also - it is retarding, not rotating. You can advance or r****d cams to alter power at rpm levels;

http://www.cranecams.com/faqview.php?s_id=8

 

[Jay Payne]

What a rotated question :S

 

[Carlv8415]

If you're after a set of 438s, I may be in a position to sell mine in the next couple of weeks. PM me if you're interested.

Also - it is retarding, not rotating. You can advance or r****d cams to alter power at rpm levels;

http://www.cranecams.com/faqview.php?s_id=8

Oh yeah so it is, learn something new every day

I will be interested I need to get my car booked into the garage but I busy for next couple weeks so won't be for a while yet.

Thanks