Since moving to a sc40 turbo and remapping to 390 hp I find the car particularly laggy. Nothing meaningful really happens till past 4k.

So I'm wondering what you guys have done to reduce the lag.

My setup
sc40
forged engine
800cc + walbro
FMIC - standard setup (would rotated inlet help much?)
3 port
ecutek by JGM
ported headers, full derestricted 3 inch exhaust and up pipe.

The lag should be improved a tiny bit on next remap as the previous map we had ICV issues when mapping and it got cut short, but I want to go back with as many improvements as possible to reduce lag and maximise the potential of the turbo.

 

AVCS heads, Smaller diameter up-pipe depending on what you have, Twin scroll headers but you will lose the burble......Rotating the inlet and compressor housing and flipping the intercooler will help but not an easy job to do on the drive ..............Oh then Meth

 

i would say at the bhp level a fmic is not needed

 

In which gear?
Flat foot in 6th @ 3k rpm will get you bu99er all, try the same in 1st and it should be whoopee time.

 

needed and wanting to make a better car is the question.
a top mount is going to suffer from heat soak badly at this level and is basically on its limit

 

Harvey/as performance up pipe will help with spool as they are designed and made for specific turbo's

Avcs can apparently bring spool down a lot and help with low down torque

Reducing the engines rotational drag will help with response as in lightened flywheel and pulleys

When my car was on the rollers we tried a run without the air filter on and it made more topend power but lost a bit of spool up, what intake setup do you have?

Is the standard airbox still efficient at 400hp?

Do you have any silencers in your exhaust? If not then a lack of back pressure can hurt spool significantly, so ive been told anyway

 

I had quite bad lag on my car when I got it. Since then have fitted RCM headers and up pipe, took it to Enginetuner for a full map and it's a different car. Still abit laggy but a hell of an improvement on what it was like.

 

Get and billet upgrade for your SC40......or strech for SC42+ (sc40 is basically td05 20g and sc42 is the smallest turbo with gt30 bb core).

What heads are you using?

You can also imporove insulation.....turbo blanket,manifold spacers,etc.

 

I don't think you need a front mount for that power,I have 427 bhp on a top mount with other supporting mods obviously an it goes like a train.thats with a sc42 by the way

 

What boost is that at and is it a standard bottom end?

 

Budget for £2k if you want to add AVCS heads, trust me I'm gong through the motions now.

From what I hear the SC42+ although slightly bigger spools like crazy.

 

It's running 2 bar of boost on a fully forged 2.1 stroker in a bugeye.perrin inlet,perrin 3 port,perrin 4 bar map sensor,full decat an a rc induction kit.an ya obvious uprated injectors an fuel pump

 

That's a lot of boost! I reckon you'll gain 20-30 bhp switching to a front mount.
Is that on a first generation sc42 if you don't mind me asking?

 

It was fitted 4 weeks ago,so it must be the new generation.yea it cud see around 460 to 500 with a front mount an meth,it had a new ecu fitted aswell forgot that bit.but I am worried I will hate it for being to laggy.great figures don't mean a great car.so its 50 50 for me at the mo

 

That seems pretty laggy.
My 2.1 with rotated GT30 0.63 on V6 heads making 1 bar at 3300 and holds 2 bar from 4200 all the way to the redline.
Winter plan is fit some trick AVCS I have built and reduce the size of the up pipe. Hoping to make full boost 3750ish

Ps also rotated the manifold so shorter pipe work

 

Lateral Inlet pipe, just a straight through job to from my air filter to turbo.

I did think lightweight flywheel as heard great things

My up pipe is a cheapo so would definitely benefit from a upgrade.


Was hoping to hold on to this turbo for a few months first

Standard ported headers.

Why such a high budget for AVCS heads?




Headers upgrading to RCM and up pipe could well be a good idea by the sound of it, did they really improve that much?

I have to keep the burble though obviously

 

3rd gear was my main example or even second isn't great at times.

Has to be above 3.5k in 2nd or above 4.5k in 3rd to feel the boost really.



Ohh and as for my exhaust, its a HKS silent power and does have a box on it.

 

I hate Turbo lag.. so really happy with my P1, it runs the standard turbo with lightened flywheel and 550 injectors, walbro and comp clutch.. 305 bhp with cat and standard air filter.

I have no lag on this car, which is why I like it so much more then the last 2 GT4 Turbos I had.

I want to get nearer 400 bhp so interested to see what advice you give scooby87

 

Because in your first post you said Ecutek

So..

£1kplus for ECU + mapping
£300-400 for the heads
£130 for head gaskets.
£75 AVCS loom
£80 oil and filter change

That's without labour, and any other odds and sods I've forgotten.

 

Ohhh....

I see, yeah I feel the money may be better spent then?

 

Think your headers are too big for the power your running, not enough back pressure by the sound of it

 

+1

Billet the wheel, FMIC, Meth