why do z20lets sound so different?

[dearing5]

random thread i know but i have always wondered why z20lets sound different to a c20let!

they have a certain growl to them an the throttle shut off seems far more responsive!

[dewismotorsport]

Be done to exhaust manifold design I'd of thought, and they are electric throttles not cable like c20lets

[dearing5]

so what's the advantage to have electronic throttle body?

[Violet]

Advantage = Mechanical vs electronic/motor driven. One works for 20 years, the other lasts five, but is in it's own 'unit' and more compact. The progression of technology.

[dearing5]

does that help to there noise? they sound so good lol love the pops on gear changes to.

[daddy cav]

does that help to there noise? they sound so good lol love the pops on gear changes to.

Noticed the pops on a Mk4 Astra GSi round here .

[welsh andy]

pops on zlets are more down to fuel,plugs and decat/sportscats. for instance i have many zlets, ph1 maps give quite a lot of pops, but just by using say cossie 071c plugs can give u pops, or by using high octane fuel, rarely have a seen a standard zlet pop, plenty of burble yes, the 2 cats on a zlet tend to stop any pops

[Tathan]

since they're geometry is identical and the block is very similar, must be basically exhaust. Some inlet too.

[welsh andy]

since they're geometry is identical and the block is very similar, must be basically exhaust. Some inlet too.

if you compare clet,zlet and zleh, you see,all pretty much the same. but the LEH pops more and the Nerd pops most, down to its sportscat, it was a 100cell, but changed to 200cell due to eml emissions codes. so you might have sumit, the LEH exhaust is 2.5" where as the Zlet is 2.25" maybe hence it pops more, espec if using vpower or other high octane fuels

[Nemesis]

My PH1 with no cat/precat pops more and is louder @ 18psi than my PH3 with cat an 26psi, also louder than my mate's 300bhp Z20LET

In other words I think the exhaust is the biggest factor

Hack it off at the downpipe and scare children.

Or in my case scare them more!

[TigraTurbo]

Λ

[welsh andy]

My PH1 with no cat/precat pops more and is louder @ 18psi than my PH3 with cat an 26psi, also louder than my mate's 300bhp Z20LET

In other words I think the exhaust is the biggest factor

Hack it off at the downpipe and scare children.

Or in my case scare them more!

my old T8 had a standard oe 2.25" exhaust with 1st cat decat and sportscat running ph3 280bhp red dot map 18psi used to pop like hell, although was running cossie plugs as well which does make a zlet pop, monday im having fitted a 200cell sports cat on my zlet as eml with 100cell along with fmic,vxr unit will flash my old red dot map bk on, still running cossie plugs, so will see if she pops more with a bigger zorst as running 3" front section and a 2.5" cat back

my old T8 wiv 3" used to sound mint my astra coupe turbo 888 turbo back prospeed 3" exhaust - YouTube

[dearing5]

hmmm maybe your right.. my old 2.5inch system used to have that growl to it. i prob just need a decent exhaust lol.

does an inlet make that much difference?

[welsh andy]

fueling plays its part too, as if you look at EDS maps they will make even a non modded zlet pop, yet a progessive map like say courtenay wont pop as much, so i think its a few factors, i dont think inlet has a part to play imo

[dearing5]

yeah i was going to say the map must play a part.

can the return spring on the tb wear out? my throttle don't close quick enough

[Violet]

I can't say I've ever appreciated the sound of a LET, they're not the greatest sounding thing.

[ccm640]

don't the exausts have a flap in on the likes of the vxr ect? if so wouldnt this make is sound like they shut of quicker due to flap shutting?

[dearing5]

aint got a clue?? why they need a flap?

[Nemesis]

don't the exausts have a flap in on the likes of the vxr ect? if so wouldnt this make is sound like they shut of quicker due to flap shutting?

Do you mean the wastegate?

[Tathan]

Lots of cars have had an exhaust valve that opens at certain revs, my 328 has one



Dunno if the VXR does but it's fairly common on sporty cars.

[daddy cav]

Lots of cars have had an exhaust valve that opens at certain revs, my 328 has one


Dunno if the VXR does but it's fairly common on sporty cars.

What , a regional Co-ord and no Vauxhall ......

[ccm640]

thanks tath you explained that alot better than i would

[redtopnutta]

i have cars with all 3 engines (z20,c20 let, and xe) my xe sounds so much better then the lets.