Turbo Lag

sleepyhead · Post by **sleepyhead** » Thu Jan 04, 2007 10:56 am

Love it or hate it?

In the mx5 circles everyone goes on about how bad lag is and how great their tubby system is as they are on full boost of xxpsi at xxxxrpm (insert silly low value like 2500). This always on characteristic kinda spoils the fun of having a tubby'd 5. For me, part of the joy is driving along in say 4th, planting your foot down and you can feel the power building and when you are on full what it pins you in and whoosh away you go! If I wanted instant go, I would have pumped for a s/c but alas I frown on the idea of stealing energy from the crank to turn a compressor, much prefer the use of exhaust gases!

So anyhow, whats your view?

duncan · Post by **duncan** » Thu Jan 04, 2007 10:58 am

Totally addicted to turbo sounds and the kick.

Tried a normally aspirated V6 for a while and it wasnt the same... I missed the whistle and fizz of the turbo

jungle-jim · Post by **jungle-jim** » Thu Jan 04, 2007 11:19 am

i kinda like the lag.

its more of a build up like you say rather than it having trouble spooling up.

it can be a pain when you are in need of more power but dropping it down a cog is too much revs and past the best power and torque of that gear.

mines larger than stock but its also a ball bearing type.

we have a really steep hill in norwich called gas hill.

my mate was having a go in mine and told him to go up there.

he turned in and he was about to put it into first.

i said no, leave it in second and put your foot down.

well, the look on his face when it reached 3,000 rpm!!

we got to the top knocking on 65 mph!! lol

god know what a bigger one would be like?

andycaca · Post by **andycaca** » Thu Jan 04, 2007 11:53 am

people commonly confuse lag with boost threshold

boost threshold is where the turbo spins up and begins to produce useful power. the bigger the turbo relative to engine displacement, the more revs you need to get things moving. this is commonly heard as "i bought a big turbo but its really laggy". no its not!

(unless you fit something silly like a T88 to a 2 litre engine)

lag is the time between planting the throttle and being pinned back in your seat. if you have a labyrinthine FMIC install, the volume is greater than a standard top mount and so this time delay will take longer. we are only talking about fractions of a second tho

where these issues are really exacerbated is when a big turbo is combined with a small engine and low revs...then you could realistically be waiting 15-20 seconds for the engine to pick up and start accellerating.

in my experience, when i went from a topmount chargecooler to a large FMIC there was very little lag introduced over the original system. i lost 2psi through the entire system but that was compensated for by adjusting the EBC. at 3000rpm or higher, it takes under half a second to go from vacuum to 18psi

for that half second, i just love the feeling of great momentum building underneath you. plus the exhaust sounds is awesome :twisted:

Christian and Beccy · Post by **Christian and Beccy** » Thu Jan 04, 2007 1:03 pm

jungle-jim wrote:we have a really steep hill in norwich called gas hill.

Gas Hill??!! I've been down that at 45mph on a push-bike!! Great fun. :-D

cannit · Post by **cannit** » Thu Jan 04, 2007 5:57 pm

My lag is waiting for VTEC!!! Its addictive, changes sound of engine and exhaust and is predictable :P

Cannit

sleepyhead · Post by **sleepyhead** » Thu Jan 04, 2007 7:00 pm

Turbo is also predictable too

:lol:

You have a good point there andycaca.

The instant go of a S/C system is nice but I'd miss all the turbo related noises and the bang in the back of the seat action

madenglishman · Post by **madenglishman** » Thu Jan 04, 2007 7:23 pm

I LOVE my agricultural turbo....for me it defines lag or boost threshold or whatever its called :-D

I'll put it into my language.......my car under 5500 rpm no real 'boost' after 5500 all hell breaks loose

.....I think Stu hates drivng my car with a single on compared to his responsive twins but I like it so I guess it's whatever floats your boat.

Saying that though a 7 litre V8 N/A would keep me happy without a turbo :-D

Post by **Stuart** » Thu Jan 04, 2007 7:25 pm

Madenglishman and I have had this chat many times. We are both disciples of the Rb26. He follows the path of singularity, I prefer the concept of twins :twisted: Dan's set up means that he has all of the anticipation of the turbo, the external wastegate, the whistle as it comes on song and the kick in the pants that epotimises large old school horsepower delivery. Mine is like a milk float in comparison but at least I can get out of corners without waiting for written permission from Mr T70 :lol:

Hand on heart~ big turbo's are lovely and if it was purely a decision made on plucking of automtive heartstrings I would have a big single with wastegate yada yada yada. I would just make sure it was strapped to an RB30 and then lag wouldn't be an issue

madenglishman · Post by **madenglishman** » Thu Jan 04, 2007 7:31 pm

Stu, your way with words is so much better than mine

....."written permission from Mr T70".....cracked me up and not far from the truth

...........race you to the unicorn of engines

....I wish!!!