Supercharged VT running out of puff

[BJ31OS]

Hi guys

My Supercharged VT seems to run out of puff at around 4500 RPM now i plan on upgrading to a 10psi pulley and cooler thermostate within the next few weeks and im hoping this might fix the problem, BUT what im wanting to know is how restrictive the stock exhaust is im thinking of just upgrading to a hi flow rear muffler to start with will it be worth it.


Cheers

[S.T.K.E]

$60 bucks. by a boost gauge and find out if your not pulling the right boost. Upgrading to a 2.5" in twin cat system is a the way to go however dont get straight throughs....... sounds frikin awesome but drones like the pope on good Friday.
Not_An_Abba_Fan should be able to hook you up with a sweet deal he seems to be throwin some good prices around

[don0xer]

if you feel its running out of guts midrange a roller rocker upgrade will help u a ton

[BJ31OS]

yeah got a boost guage sitting at home will put it in the same time i get the 10 psi pulley done.

roller rockers are on the list aswell hopefully for early next year

[S.T.K.E]

I'd probably say that if you feel like its lacking something get a tune the same time your throw the pulley on there........ just in case you throw fuel into the fire, but if your doing the pulley upgrade your gonna want that exhaust

[chargedvx6]

I wouldn't worry about exhaust until a few more mods have been done. It's just for noise until you get up around 150rwkw (stock is around(110-115rwkw).

Check your fuel filter isn't blocked and give the MAF a clean with the proper spray and you may see a good improvement

[BXHD]

Go onto the FIT website. apparently if you do extractors and exhaust before anything else, it doesnt get very good results. the 10psi pulley thing is the best idea to start with

[chargedvx6]

87mm pulley, CAI improvements, high ratio rockers then an exhaust would come into play in my experience

[BJ31OS]

87mm pulley, CAI improvements, high ratio rockers then an exhaust would come into play in my experience

Thats the plan im going down. have already done the CAI and 10 PSI pulley will be ordered next week.

[Tsunamix]

It shouldnt be running out of puff at 4500, peak torque is around 3400, should be going hard for another 1000rpm at least...

Maybe your getting some belt slip ? check tension on belts recently ?

Just had another thought - Your supercharger bearings may be binding - meaning that the higher the revs, the more friction on your chargers rotor, reducing its ability to rotate freely. This may force belt slip as well.

WEhatever it is, to be running out of puff - yet still running smoothly and not roughly, suggest that there is an impediment to airflow. Unlikely to be fuel or spark, because it is still running smoothly.

[chargedvx6]

The stock super 6 is kniwn for not having much up top. Get a few mods into it would be my suggestion. They respond very well everywhere once these are done

[emmtee83]

Great thread!

I'm suffering from the same thing in my VT.....i'm putting on a 12psi pulley next week.

I'm thinking of running a diagnostic tool to see if there are any other errors in the system, would that be a good idea?

Thanks for any help.....

[alien]

Everyone with stock L67's need to stop posting these questions. Your torque rating is charted at 3000-3400 RPM. After that it's designed to go into the next gear around 4500rpm and still be in torque range. The autos though have a lack of gears to be able to get you going, the reason why the V8's will start gaining speed at around 100-110km/h.

However, to get it to keep going you can do the mods like listed above to get more power, but you will end up with the same problems at some point unless you do something different.

[vsl67]

Go onto the FIT website. apparently if you do extractors and exhaust before anything else, it doesnt get very good results. the 10psi pulley thing is the best idea to start with

My l67 stato had an oversized exhaust & extractors when I got and no other mods and it killed off power until I done other mods but one of the best mods I done was a corvette servo its nice and cheap and get results ,also be very careful what you run it on if you use cheap fuel dont expect too much power from it because your computer will retard the timing due to the lower octane rating

[chargedvx6]

Great thread!

I'm suffering from the same thing in my VT.....i'm putting on a 12psi pulley next week.

I'm thinking of running a diagnostic tool to see if there are any other errors in the system, would that be a good idea?

Thanks for any help.....

Just go an 87mm pulley for best results. The 78mm is too small for a relatively stock L67.

[emmtee83]

Everyone with stock L67's need to stop posting these questions.

Alien,

Maybe not everyone who has an L67 knows their cars inside out, like you do.

How's about answer the questions asked by members. If you're hear to help out, thats great.....if you're here to criticise, then keep your thoughts to yourself.

PS - Thanks for your help chargedvx6!

[HARVZ-6]

My l67 stato had an oversized exhaust & extractors when I got and no other mods and it killed off power until I done other mods but one of the best mods I done was a corvette servo its nice and cheap and get results ,also be very careful what you run it on if you use cheap fuel dont expect too much power from it because your computer will retard the timing due to the lower octane rating

a key point made there

run atleast 95prem unleaded or it will run like crap especially up top under load where it starts to ping and sets the computer into a fit haha

youll notice it doing this because itll lag for a few hundred revs.. then pic up again then lag down again and so on