TeamSwift

Home of the Suzuki mini-compacts ! Your Home for all things Suzuki Swift, Geo Metro, Holden Barina, Chevy Sprint, Pontiac Firefly, and Suzuki Cultus. TeamSwift is a technical performance oriented community!
It is currently Wed Nov 22, 2017 6:16 am

Underbody braces, turbos and more!

All times are UTC - 5 hours




Post new topic Reply to topic  [ 39 posts ]  Go to page 1, 2  Next
Author Message
PostPosted: Sat Sep 09, 2006 7:40 pm 
Offline
Moderator
Moderator
User avatar

Joined: Sun Feb 23, 2003 4:16 am
Posts: 8042
Location: Ontario, Canada
How to add fuel when you need it most.

The coolant temp sensor (cts) mod is an easy, and inexpensive way to add fuel when increasing boost on your turbo3, adding a turbo to your non-turbo car, or fixing a lean condition, due to the addition of cams, etc.
It is not a rplacement for a standalone, nor will it work as well as a piggyback computer. It is, however, crude, cheap, and relatively effective.
Before you start, you ned to install an air/fuel ratio gauge, in order to monitor your fuel activity, and prevent from running lean.

The cts is a Negative Temperature Coefficient (NTC) Thermistor. What this means is that as the temperature of the ECT Sensor rises, the resistance of it drops. This chart (of a generic cts) shows how temperature affects resistance.

Image


By adding resistance to the circuit (between the ECU, and the CTS), you can trick the computer into thinking the motor is running colder. It will respond by adding fuel to richen the mixture.

Adding resistance.

You can see, on the graph, that the normal operating temp resistance should be in and around about 300 ohms.
At 0 degrees C, the resistance is roughly 6000 ohms.
Its difficult to determine exactly how much extra fuel you will need, so I like to start out with a 5k pot (5000 ohm potentiometer). The type of pot you need is a one turn, linear pot, and can be bought from any electronics supply for a few dollars, if that.
You need to locate the CTS. There will be two wires coming from it, leading to the ECU. You want to cut one of the wires, and wire it in series between the CTS and the ECU. By adding resistance to the circuit, the ECU believes the engine is colder and makes the changes almost instantaneously.
The mod will work fine like this for very small changes in boost, or for modified naturally aspirated cars. For increased boost, you need a way to introduce the circuit at a certain boost level. to prevent it from running grossly rich at stock/no boost levels.
A pressure switch can be added to the circuit, to enable the the mod at predetermined boost levels.
Hobbs makes nice adjustable pressure switches, and occassionally, you can find some nice ones reasonably priced on ebay.
After installation, you'll want to verify that you have installed the pot, not only in the correct position, but also correctly phased.
It is possible to install it backwards, such that resistance is decreased as the pot is turned clockwise. Ussually, you will use the 2 left most terminals.
To do this, turn it up all the way, and enable the circuit (if a pre. sw. is being used) at idle. The car should get very rich, stumble, and stall. If not, try turning it all the way down.. If this does it, you have the pot wired backwards.

Pros

Cheap
Adjustable
Simple, and reliable
Effective at reasonable boost levels
Duty cycle wil increasae as a factor of RPM, and load, unlike mods like the cold start inj. mod.
Will work with all OBD 1 ECU's

Cons

Although a big step up from mods like the cold start inj. mod, it still is a crude method of adding fuel, and no replacement for standalones, etc.
Only so much fuel will be available from the stock injectors.
It will work only as long (pr. sw. application) as you are at the predetermined boost level, so part throttle boost can get lean, and dangerous. BE CAREFUL!!
If it fails for any reason, you're toast.

I have succesfully used this mod on my Mk1, and Mk2 cars, to run boost levels of 25psi, on an otherwise stock motor. The Mk1 is currently running 15-18 psi with a mild performance cam, and stock turbo with the wastegate disconnected, and this mod for extra fuel. I use it a WOT only!

_________________
Contact 3tech: g10pro@rocketmail.com


Last edited by suprf1y on Tue Sep 12, 2006 5:55 am, edited 3 times in total.

Top
 Profile  
 
 Post subject:
PostPosted: Sat Sep 09, 2006 11:52 pm 
Offline

Joined: Thu May 19, 2005 1:49 pm
Posts: 545
Location: Ontario
can this mod be done with gti's?


Top
 Profile  
 
 Post subject:
PostPosted: Sun Sep 10, 2006 12:03 am 
Offline
Moderator
Moderator
User avatar

Joined: Sun Feb 23, 2003 4:16 am
Posts: 8042
Location: Ontario, Canada
SSGTi12345 wrote:
can this mod be done with gti's?


Yes.

_________________
Contact 3tech: g10pro@rocketmail.com


Top
 Profile  
 
 Post subject:
PostPosted: Sun Sep 10, 2006 2:44 am 
Offline
Island Inbreeder
User avatar

Joined: Tue Oct 18, 2005 6:56 pm
Posts: 6347
Location: Emerald city Washington
Mike yes we tried some thing like this on Hooptie/TMD 92 vert only it was a single resistor in series the the MAF
instruction said it would fool the ECM to think the air temp in the engine was cooler to alowy more fuel
got it on Ebay claimed to inprove preformance NFW

I read on this forum a while back were some one jimmy rigged the cold start injector so it would open and let more fuel in @ WOT with a pressure switch

What your take ??
.
Please don't think for a minuet i'm bashing you in any way
I have nothing but respect for you
you know that

Hell i'm still running with one of your cam on "Elturdbo" MK1 turbo
and couldn't be happy'r

. BTW your post almost put me to sleep My A.D.D.
was kicking in could you use more spaces and comas shorter sentence
Sorry

.

I do have A/F gage and do get a lean condition when boosting hard over
5G (yah i know then don't go over 5G)

I just get nervous when you say if it fails it will go LEAN (Turbo Death)
At least I think that's what your saying here --

("It will work only as long (pr. sw. application) as you are at the predetermined boost level, so part throttle boost can get lean,")

Do you have a picture of a (8000-5000ohm) adjusable pot I could try
and this hobbs pressure switch ??

Also can you tell me what kind of BOV are you running
on your MK1 with mild cam boosting 15-18
(please don't say a gen 1 DSM BOV ) Pictures ??
.
.
.JV&S ---------------
.
.
.
.
.


Top
 Profile  
 
 Post subject:
PostPosted: Sun Sep 10, 2006 3:28 am 
Offline
Moderator
Moderator
User avatar

Joined: Sun Feb 23, 2003 4:16 am
Posts: 8042
Location: Ontario, Canada
I used the cold start injector, and even rigged up 2 of them on my Mk2 car. It works, but is even cruder than the CTS mod.
Your ebay thing is the right idea, just likely the wrong resistance value.

Quote:
BTW your post almost put me to sleep My A.D.D.
was kicking in could you use more spaces and comas shorter sentence
Sorry

You should be sorry with sentence structure, spelling, and punctuation like that.
Learn to read. =)
If it fails, it will most likely be operator error.
Do a search for Hobbs. Also look on ebay.
I am not using a BOV.

_________________
Contact 3tech: g10pro@rocketmail.com


Top
 Profile  
 
 Post subject:
PostPosted: Wed Dec 06, 2006 3:01 pm 
Offline

Joined: Thu Jan 06, 2005 4:02 pm
Posts: 149
Location: Payson, Utah
Do any one of pic of this setup?


Top
 Profile  
 
 Post subject:
PostPosted: Wed Jan 03, 2007 2:26 am 
Offline

Joined: Mon Jan 01, 2007 4:15 pm
Posts: 97
Location: Vancouver
I've never heard of something like this before. Its a damn good idea.

One of the cons mentioned was the extra fuel being added only at predetermined levels. Wouldn't it be possible to run 2 sets of potentiometers/pressure switches. The first set with a lower pressure setting connected to a potentiometer with a resistance that would allow for a smaller increase in fuel, then a second set with a higher pressure setting set for a larger fuel increase. Would you be able to run in it two steps like that instead of simply on/off?


Top
 Profile  
 
 Post subject:
PostPosted: Wed Jan 03, 2007 10:18 pm 
Offline
User avatar

Joined: Fri Apr 09, 2004 2:27 pm
Posts: 763
Location: Toronto, Ontario
totally possible just have the boost pressure switch set in different stages ( different boost levels)

Steve

_________________
91 suzuki swift GT - UNDER PRESSURE Summer Sleeper.
04 Acura tsx - daily driver.

Turbo lag? huh? nah! just traction lag :censor: :furious:

psssshh! don't tell anyone :ez_evil:

BTW GTi = Great Tiny Import :P


Image, Image


Top
 Profile  
 
 Post subject:
PostPosted: Fri Feb 16, 2007 3:05 pm 
Offline
User avatar

Joined: Wed Sep 28, 2005 1:28 pm
Posts: 400
Location: San Antonio, Texas
As asked above: Does anyone have a picture of how they hooked theirs up?

_________________
Things that go "BOOM" in the night ! Hopefully not the 1.0.
Member#3307 ??


Top
 Profile  
 
 Post subject:
PostPosted: Fri May 18, 2007 7:58 pm 
Offline

Joined: Wed May 09, 2007 8:41 pm
Posts: 19
What about using a map sensor in place of the pot?
If you had one wired so it would increase resistance as manifold pressure goes up, then it would, as I'm led to believe, inrease the amount of extra fuel as boost went up.


Top
 Profile  
 
 Post subject:
PostPosted: Sun Jul 01, 2007 9:29 am 
Offline
User avatar

Joined: Sun May 20, 2007 8:19 pm
Posts: 96
Location: Winnipeg Manitoba
all depends on the voltage right, but after looking at the graph it's almost crazy enough to work if the voltage on that graph is accurate for how much voltage a Swift CTS uses...

However after some looking a Turbododge 2.2/2.5 Map sensor might be just the ticket because of the range it works in. With the turbo dodge map 14.7 psi would be 5v. It rises as boost pressure is increased

_________________
93 Geo Metro - 3Tech 10 Degree Pulley, UDP, Foam Intake, Two Brothers Racing Muffler


Top
 Profile  
 
 Post subject:
PostPosted: Sun Jan 20, 2008 3:44 pm 
Offline
Sad but True...

Joined: Fri Jul 27, 2007 8:20 pm
Posts: 2973
Location: Saskatchewan
I plan on doing this for the high compression + 12psi sprint. I will add just a resistor inline to think its slightly colder than it is, to help compensate for the higher compression, and I will do the pot aswell, so I can turn it up when I wanna get hard on it. I blew it up once bagging it everywhere, this time I plan to be a little nicer, but get onner when I need to ;)

this is a good write up, question though, doesnt the engine temp have anything to do with ignition timing aswell? or is that purely maf calculated? I was under the impression that the colder the motor the more fuel + timing there is, maybe it depends on the car?

_________________
1991 Swift GT Build G10 +25 psi + other goodies
1996 Metro Build QR25de swap, still undecided where to take it
the lolcar family


Top
 Profile  
 
 Post subject:
PostPosted: Tue Jan 22, 2008 4:19 am 
Offline
User avatar

Joined: Mon Apr 14, 2003 11:31 pm
Posts: 2457
Location: New York State
swift13b wrote:
doesnt the engine temp have anything to do with ignition timing aswell? or is that purely maf calculated? I was under the impression that the colder the motor the more fuel + timing there is, maybe it depends on the car?

If you have no vacuum advance, the water temp probably affects timing. I know it does on the 1.3L engines that my '91/'92 Swift service manuals cover, but the exact relationship is not given. The air temp sensor does not change timing, you could experiment with that too.

_________________
1994 Metro - MPH project (getting a DOHC G13B)
1994 Metro - MPG project (getting an XFi G10)
1992 Swift - Parts car (gone)
1991 Swift - Parts car (gone)
1990 Swift - Parts car
1997 Metro - Parts car (gone)
1993 Metro - Parts car
1989 Swift GTi - Parts car
1998 Metro - Parts car


Top
 Profile  
 
 Post subject:
PostPosted: Tue Jan 22, 2008 9:21 am 
Offline
Moderator
Moderator
User avatar

Joined: Sun Feb 23, 2003 4:16 am
Posts: 8042
Location: Ontario, Canada
More likely the colder the motor the less timing. I thought I read that in one of the service manuals, but don't recall which one.


Top
 Profile  
 
 Post subject:
PostPosted: Tue Jan 22, 2008 9:48 pm 
Offline
User avatar

Joined: Mon May 27, 2002 11:47 pm
Posts: 1974
Location: San Juan, Argentina
the colder the motor, the earlier the ignition

It advances timing a bit.

_________________
Megasquirt tutorial --- http://caaarlo.50megs.com


Top
 Profile  
 
 Post subject:
PostPosted: Wed Jan 23, 2008 3:57 am 
Offline
User avatar

Joined: Mon Apr 14, 2003 11:31 pm
Posts: 2457
Location: New York State
According to the very vague graph in my '92 supplement, the timing on the SOHC 1.3L is retarded a little at very cold temps and retarded a lot at high temps. But the graph has no numbers and there is no graph for the DOHC. :roll:

_________________
1994 Metro - MPH project (getting a DOHC G13B)
1994 Metro - MPG project (getting an XFi G10)
1992 Swift - Parts car (gone)
1991 Swift - Parts car (gone)
1990 Swift - Parts car
1997 Metro - Parts car (gone)
1993 Metro - Parts car
1989 Swift GTi - Parts car
1998 Metro - Parts car


Top
 Profile  
 
PostPosted: Wed Feb 27, 2008 12:32 am 
Offline

Joined: Tue Sep 25, 2007 10:24 pm
Posts: 257
Location: Edmonton, Alberta, Canada
Hello, I have this mod installed, and working properly on my MK2. I have, however encountered a small issue.

On 13psi, it supplies enough fuel under throttle, however, when shifting hard, it bogs hard upon the throttle opening into the next gear. This problem is greatly reduced as I turn down the knob on the pot, however this also reduces the fuel I get up top, making the car knock slightly.

I am not getting the best of both worlds, I get great power up top, but get into a huge bog upon rapid gearshifts in boost. I am running an atmospheric BOV as well, and I think this could be the culprit...

Any insight into what I can do to keep fuel up top, but reduce this race-losing bog during shifts?

_________________
MK2 Firefly -- RHB5, SAFC Neo, 626 Turbo Injectors, Custom Equal Length Manifold.

SOLD!


Top
 Profile  
 
 Post subject:
PostPosted: Wed Feb 27, 2008 12:46 am 
Offline
Moderator
Moderator
User avatar

Joined: Sun Feb 23, 2003 4:16 am
Posts: 8042
Location: Ontario, Canada
What is your pressure switch set to?
You shouldn't need much fuel to compensate at that low boost level.


Top
 Profile  
 
 Post subject:
PostPosted: Wed Feb 27, 2008 12:53 am 
Offline

Joined: Tue Sep 25, 2007 10:24 pm
Posts: 257
Location: Edmonton, Alberta, Canada
Pressure switch is 7psi.

From what I've read, the CTS mod somehow is much more effective on the MK1 motors, and it really doesn't help me out much...

I lean out at 15psi with it, and with it turned off, I'm lean at 12.

_________________
MK2 Firefly -- RHB5, SAFC Neo, 626 Turbo Injectors, Custom Equal Length Manifold.

SOLD!


Top
 Profile  
 
 Post subject:
PostPosted: Wed Feb 27, 2008 1:36 am 
Offline
Moderator
Moderator
User avatar

Joined: Sun Feb 23, 2003 4:16 am
Posts: 8042
Location: Ontario, Canada
clys wrote:
Pressure switch is 7psi.

From what I've read, the CTS mod somehow is much more effective on the MK1 motors, and it really doesn't help me out much...

I lean out at 15psi with it, and with it turned off, I'm lean at 12.


Then you're doing something wrong.
Tell me where you read that.
It works equally well on both Mark 1, and Mark 2's.
If you lean out at 12, then why is the switch set at 7?
Set it at 10.
You should have enough fuel with the mod to run 25+ psi boost.
What size pot are you using?


Top
 Profile  
 
 Post subject:
PostPosted: Wed Feb 27, 2008 1:38 am 
Offline

Joined: Tue Sep 25, 2007 10:24 pm
Posts: 257
Location: Edmonton, Alberta, Canada
It's a 10kohm pot I believe.

I don't know what I could be doing wrong, it's definitely engaging, and adding fuel, but not enough to run more boost...

And that nasty bog...

_________________
MK2 Firefly -- RHB5, SAFC Neo, 626 Turbo Injectors, Custom Equal Length Manifold.

SOLD!


Top
 Profile  
 
 Post subject:
PostPosted: Wed Feb 27, 2008 9:06 am 
Offline
Moderator
Moderator
User avatar

Joined: Sun Feb 23, 2003 4:16 am
Posts: 8042
Location: Ontario, Canada
Try using a 5k pot.
It sounds like you have a 1k


Top
 Profile  
 
 Post subject:
PostPosted: Wed Feb 27, 2008 11:22 am 
Offline

Joined: Tue Sep 25, 2007 10:24 pm
Posts: 257
Location: Edmonton, Alberta, Canada
Alright, will look into that asap. Thanks super unit. Any ideas on that bog though?

When I'm racing d00ds, I reel them in every gear, but I lose so much ground when shifting, it's not cool in the slightest!

Powershifting, keeping the throttle at WOT solves this issue, though.

_________________
MK2 Firefly -- RHB5, SAFC Neo, 626 Turbo Injectors, Custom Equal Length Manifold.

SOLD!


Top
 Profile  
 
 Post subject:
PostPosted: Wed Feb 27, 2008 11:59 am 
Offline

Joined: Tue Sep 25, 2007 10:24 pm
Posts: 257
Location: Edmonton, Alberta, Canada
http://cgi.ebay.ca/10K-Potentiometer-with-Switch-PANEL-MOUNT-5_W0QQitemZ180217942481QQihZ008QQcategoryZ58164QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

Would this be a proper pot?

_________________
MK2 Firefly -- RHB5, SAFC Neo, 626 Turbo Injectors, Custom Equal Length Manifold.

SOLD!


Top
 Profile  
 
 Post subject: Re:
PostPosted: Sat Jul 26, 2008 4:42 pm 
Offline
User avatar

Joined: Wed Sep 28, 2005 1:28 pm
Posts: 400
Location: San Antonio, Texas
metro freak wrote:
As asked above: Does anyone have a picture of how they hooked theirs up?



And I ask again, Is there a wiring diagram and does someone have a picture or tech write up on how they did theirs.

_________________
Things that go "BOOM" in the night ! Hopefully not the 1.0.
Member#3307 ??


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 39 posts ]  Go to page 1, 2  Next

All times are UTC - 5 hours


Who is online

Users browsing this forum: Bing [Bot] and 1 guest


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB® Forum Software © phpBB Group