| Author | Topic |
|---|
Location:
Adelaide
Registered:
September 2003
|
|
General forced induction questions
|
Mon, 09 May 2005 07:49
|
 |
Hi all,
just a few questions to help my understanding of forced induction:
1. To add forced induction to a N/A car it is usually best to lower compression..is there a specific amount to lower it too?
eg. for a 4 cylinder motor wanting to run 10-15psi do you drop it to 8.8:1 or 9.1:1 or 9.6:1 etc etc? (or does this differ greatly for ALL engines?)
2. How does lowering the compression affect 'off boost' driving?
3. When adding forced induction (assume turbo not supercharger) to an N/A car what other things would you need to consider 'internal' to the engine?
ie. Forged pistons (lower compression rate), forged rods, springs and valves, ??
Cheers for any answers.
*Try not to flame me too much - I did search and debated a fair few times before posting this*
|
|
|
I supported Toymods
Location:
Australia
Registered:
November 2003
|
|
Re: General forced induction questions
|
Mon, 09 May 2005 07:59
|
|
1) Depends on intake temps and above all, Tuning.
2) Will reduce off boost torque. Less torque = worse to drive
3) Have a look at what turbo engines have, forgies are good but once again, is in the tuning, some have oil squirters, oil coolers etc etc.
|
|
|
Location:
Toronto, Downtown
Registered:
September 2004
|
|
Re: General forced induction questions
|
Mon, 09 May 2005 08:04
|
|
|
the biggest part of keeping an originally n/a engine together when adding boost is keeping detonation away it is important to do this is any motor but more so in an engine that wasnt designed with forced induction in mind
|
|
|
Location:
MELBOURNE
Registered:
December 2004
|
|
Re: General forced induction questions
|
Mon, 09 May 2005 10:44
|
|
I want to know the answers to these aswell!
Thanks
Troy
|
|
|
Location:
Adelaide
Registered:
September 2003
|
|
Re: General forced induction questions
|
Tue, 10 May 2005 06:16
|
|
So basically there is no real 'standard setup' to aim for, nor any real guidelines....
which leads me to the next few questions:
Is it possible to lower compression too much, and have a pig of a car to drive off boost? (Given the application I don't think that will be a problem but still better to ask now rather than whinge later.)
If lowering compression affects off boost torque - is it possible that if you lower the compression too far, that you will increase spool time on a turbo?
(although if you pick a suitable turbo for the application one would assume that problem wouldn't exist...?)
When you say it's all in the 'tuning' what exactly does that mean?
eg. ecu setup, injector setup, cam lift and duration etc etc or all of the above and all of the etc etcs?
Cheers again for answer so far.
|
|
|
I supported Toymods
Location:
Australia
Registered:
November 2003
|
|
Re: General forced induction questions
|
Tue, 10 May 2005 06:20
|
|
Its all in the tuning means the tune needs to be perfect.
A couple of degrees extra timing can cause detonation, a few % not enough fuel can cause detonation.
An NA-T really needs to have stand alone management if you want to put in more than 6ish psi.
And don't lower the compression much past 8.5:1
I'd be aiming around 9:1 unless you want high boost.
A 9.5:1 with mid boost will be nicer to drive than an 8.5:1 with high boost, especially on a 4cyl.
It won't put out as much power, and will be slower at the drags, but will much nicer to drive.
|
|
|
Location:
Toronto, Downtown
Registered:
September 2004
|
|
Re: General forced induction questions
|
Tue, 10 May 2005 06:50
|
|
|
agreed more comp and less boost is more desireable better to pull another gear and ride the torque instead of reving it out
|
|
|
Location:
Adelaide
Registered:
September 2003
|
|
Re: General forced induction questions
|
Tue, 10 May 2005 09:48
|
|
Thanks guys for answering my questions 
If I think of more I'll ask - also appreciate not flaming me for asking 'newbie type' questions.
Cheers.
|
|
|
Location:
Hunter Valley
Registered:
February 2003
|
|
Re: General forced induction questions
|
Tue, 10 May 2005 09:49
|
|
I have had little (basically no) experience with turbos.
I am confused about all the piping haha.
Is there a diagram anywhere? I know that the turbo runs from exhaust fumes on the exhaust side, but how does it supply more air into the the engine as it doesnt link up with the intake? And where does the piping from the intercooler fit into it all?
Sorry, but once I have an understanding of the general engine setup, everything else will fall in place for me.
|
|
|
I supported Toymods
Location:
Australia
Registered:
November 2003
|
|
|
