Notices
944 Turbo and Turbo-S Forum 1982-1991
Sponsored by:
Sponsored by: Clore Automotive

5th Injector?

Thread Tools
 
Search this Thread
 
Old 03-18-2013 | 09:22 PM
  #1  
Tedro951's Avatar
Tedro951
Thread Starter
Three Wheelin'
 
Joined: Feb 2007
Posts: 1,408
Likes: 0
From: Indianapolis,IN
Default 5th Injector?

Should I?
Old 03-18-2013 | 09:24 PM
  #2  
eman930's Avatar
eman930
Banned
 
Joined: May 2004
Posts: 1,919
Likes: 14
From: CT
Default

Originally Posted by Tedro951
Should I?
What's ur setup and goal?
Old 03-18-2013 | 09:30 PM
  #3  
Crazy Eddie's Avatar
Crazy Eddie

Rennlist Member

 
Joined: Feb 2004
Posts: 6,985
Likes: 69
From: Los Altos, CA
Default

Originally Posted by Tedro951
Should I?
Your timing is hilarious


Brest regards
Ed
Old 03-18-2013 | 10:08 PM
  #4  
blown 944's Avatar
blown 944
Race Car
 
Joined: Jul 2007
Posts: 4,826
Likes: 4
From: Firestone, Colorado
Default

Had a longer response written but my phone betrayed me.

I've measured individual cylinders and they are very consistent.

Was in inexpensive solution to get much needed fuel.

I ran it from 17:1 lean cruise to 11.4 at 22psi.


I can switch to a 4 injector setup and do back to back dyno runs next time. Not a bad idea). Josh has written tunes for both in my chip.

AITs are cooler. If thats any help. Idk which would make more power, but it worked well for me.
Old 03-18-2013 | 10:10 PM
  #5  
Black51's Avatar
Black51
Three Wheelin'
 
Joined: May 2010
Posts: 1,956
Likes: 9
From: Edmonton, AB
Default

Originally Posted by Crazy Eddie
Brest regards
Nice.
Old 03-18-2013 | 10:15 PM
  #6  
Tedro951's Avatar
Tedro951
Thread Starter
Three Wheelin'
 
Joined: Feb 2007
Posts: 1,408
Likes: 0
From: Indianapolis,IN
Default

Originally Posted by fast924S
Originally Posted by Tedro951
Should I?
What's ur setup and goal?
I'm contemplating a custom 3.15l striker build...
Old 03-19-2013 | 12:46 AM
  #7  
Tom M'Guinn's Avatar
Tom M'Guinn

Rennlist Member

 
Joined: Jan 2002
Posts: 12,567
Likes: 536
From: Just CA Now :)
Default

Originally Posted by blown 944
Had a longer response written but my phone betrayed me.

I've measured individual cylinders and they are very consistent.

Was in inexpensive solution to get much needed fuel.

I ran it from 17:1 lean cruise to 11.4 at 22psi.


I can switch to a 4 injector setup and do back to back dyno runs next time. Not a bad idea). Josh has written tunes for both in my chip.

AITs are cooler. If thats any help. Idk which would make more power, but it worked well for me.
What circuitry/controller are you using to drive that injector -- the DME injector drivers? I'm plotting a course for water/meth injection using the PWM valve from Aquamist -- which is like a 5th injector in some ways. I'm torn between using the Aquamist full blown controller, the Vitesse piggyback or my own homebrew controller (since I'm on an Arduino kick these days), so curious to hear how you are controlling yours?

I made 500 to the wheels on four 83lb injectors with 11.5:1 AFR, so I suspect there are very few folks here who need more fuel than is availble from 4 cheap realiable injectors....
Old 03-19-2013 | 12:48 AM
  #8  
refresh951's Avatar
refresh951
Rennlist Member
 
Joined: Jun 2010
Posts: 3,365
Likes: 22
From: Marietta, Georgia
Default

Originally Posted by Tom M'Guinn
I made 500 to the wheels on four 83lb injectors with 11.5:1 AFR, so I suspect there are very few folks here who need more fuel than is availble from 4 cheap realiable injectors....
What fuel Tom? We are using E85.
Old 03-19-2013 | 01:01 AM
  #9  
blown 944's Avatar
blown 944
Race Car
 
Joined: Jul 2007
Posts: 4,826
Likes: 4
From: Firestone, Colorado
Default

Tom, you'll have to ask Josh exactly how he does it. I just get the benefit. I think it's just spread out amongst 5 injectors rather than 4.

I needed the fifth injector once I hit the 123-124 mark (happened when I went gown in elevation initially) So just under 500 rwhp. I agree, not many will need more than the 4-80# units Josh sells. One thing to note with these injectors is that they ramp up close to max duty cycle. As of now, IIRC, I'm at around 85-90% with the five.

We have talked about 8 injectors for this next round.

I mostly leave all that to Josh to figure out.
Old 03-19-2013 | 01:24 AM
  #10  
Tom M'Guinn's Avatar
Tom M'Guinn

Rennlist Member

 
Joined: Jan 2002
Posts: 12,567
Likes: 536
From: Just CA Now :)
Default

Originally Posted by refresh951
What fuel Tom? We are using E85.
Oh, right, good point. Here in the land of weekly smog checks, illegal yule logs, and 3 variations of eco-friendly brake cleaner, E85 is inexplicably hard to find. I do have two stations that sell 100 octane nearby however.
Old 03-19-2013 | 01:54 AM
  #11  
Rogue_Ant's Avatar
Rogue_Ant
Addict
Rennlist Member

Rennlist
Small Business Partner

 
Joined: May 2006
Posts: 5,252
Likes: 6
From: Denver
Default

Originally Posted by Tom M'Guinn
What circuitry/controller are you using to drive that injector -- the DME injector drivers? I'm plotting a course for water/meth injection using the PWM valve from Aquamist -- which is like a 5th injector in some ways. I'm torn between using the Aquamist full blown controller, the Vitesse piggyback or my own homebrew controller (since I'm on an Arduino kick these days), so curious to hear how you are controlling yours?

I made 500 to the wheels on four 83lb injectors with 11.5:1 AFR, so I suspect there are very few folks here who need more fuel than is availble from 4 cheap realiable injectors....
With your low-impedance injectors, my method of controlling 5-injectors cant be done with the stock DME injection driver. (you will pull too much current)

Originally Posted by refresh951
What fuel Tom? We are using E85.
Yep - E85 means ~30-35% more fuel required for the same airflow. While 80# injectors will do 500rwhp on gas, E85 is a different story.

Last edited by Rogue_Ant; 03-19-2013 at 02:16 AM.
Old 03-19-2013 | 03:35 AM
  #12  
Adonay's Avatar
Adonay
Rennlist Member
 
Joined: Aug 2009
Posts: 844
Likes: 12
From: norway and or sweden
Default

I dont see the point .
Get 4 higher flowing injectors and be done with it.
It may cost more but will fit with out modifications and "experimenting". Your engine Your choice .
Old 03-19-2013 | 04:38 AM
  #13  
Dougs951S's Avatar
Dougs951S
Race Car
 
Joined: Mar 2012
Posts: 3,602
Likes: 8
From: Austin TX, drinking beer in the garage
Default

I think experimentation is great. Its like a toolbox, or an artists' palette, always nice to have more than one way to do things. This is the type of experimentation that yields advances brings our cars OUT of the 80's even if it seems delightfully stone age to some. Nothing wrong with not doing things "by the book."
Old 03-19-2013 | 09:58 AM
  #14  
carlege's Avatar
carlege
Drifting
 
Joined: May 2009
Posts: 2,530
Likes: 1
From: Atlanta, Ga
Default

Josh where you guys mounting this 5th injector. Could location and type of injector also play a key in getting the fuel dispursed correctly?
Old 03-19-2013 | 12:08 PM
  #15  
blown 944's Avatar
blown 944
Race Car
 
Joined: Jul 2007
Posts: 4,826
Likes: 4
From: Firestone, Colorado
Default

I'll answer since it was on my car. The injector is mounted right after the inter cooler. I do think that the injector style plays a role in effectively atomizing the fuel within the incoming air.

I would like to take a step back and say that it may not be the solution for everyone. If I were starting from scratch, I'd just go with 100# units. That was not the case and Josh wanted to test out the fifth injector and I needed more fuel. We already had the tune set for the 4, so he saved that tune and mapped a tube for the fifth. So switching between the tunes was as easy as un plugging the injector and changing the coding plug. I was surprised how little difference there was in terms of drive ability.

It works great and saved me about $5-600

However, there are risks as well. Say one injector fails, you only get fuel from the fifth. That would equal a burnt piston. Pretty unlikely though. I keep a pretty good eye on AFRs, and EGT's So a little different than most.


Quick Reply: 5th Injector?



All times are GMT -3. The time now is 06:25 PM.