Technical after the fact question
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TECH Enthusiast
Joined: Nov 2001
Posts: 650
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From: Toronto, Canada
Technical after the fact question OK, not that I'm about to change anything but I have a question about my combination and it's potential efficiency. I'm really thinking out loud before it's finished and there might be small changes I can make.
I've read a great deal about turbos, looked at VE tables, but have not been able to figure out what to expect from a specific combination. The part names aren't that important for this question
Here is the important information and I'm wonderingif some can help me figure out how efficient the system should be. I'm looking for potential back pressure issues, efficiency range, power potential at various boost ranges etc.
I've provided a pic out of the car for reference so you can easilly see the piping and overall setup
Motor - Resleeved Aluminum 391 CID
4" bore X 3.875 Stroke
-25 cc dished pitons 8:1 compression
Stage II heads max fow 320 CFM @ 600 lift
2.05 intake X 1.85 exhaust
LS6 Intake
Cam - 234/230 618/591 115
Hot side - PTE T88 .96 AR housing
1 5/8 primaries
3" Collector
4" Downpipe to a 3" reducer at the cat-back
80mm HKS wategate
Cold side - 1800 CFM FMIC Air to Air
3" Aluminum tubing
Conical top mount high flow filter
80mm HKS BOV
Fuel system - Twin Walboro 340 intake pump
C5 Fuel rail with return of rail
Boost referenced AFPR set at 50 psi base
60 lb Mototron injectors @ 48 psi
I think I got the important parts covered and I'd like to hear some opinions and if there is anything I omitted
.JPG)
I've read a great deal about turbos, looked at VE tables, but have not been able to figure out what to expect from a specific combination. The part names aren't that important for this question
Here is the important information and I'm wonderingif some can help me figure out how efficient the system should be. I'm looking for potential back pressure issues, efficiency range, power potential at various boost ranges etc.
I've provided a pic out of the car for reference so you can easilly see the piping and overall setup
Motor - Resleeved Aluminum 391 CID
4" bore X 3.875 Stroke
-25 cc dished pitons 8:1 compression
Stage II heads max fow 320 CFM @ 600 lift
2.05 intake X 1.85 exhaust
LS6 Intake
Cam - 234/230 618/591 115
Hot side - PTE T88 .96 AR housing
1 5/8 primaries
3" Collector
4" Downpipe to a 3" reducer at the cat-back
80mm HKS wategate
Cold side - 1800 CFM FMIC Air to Air
3" Aluminum tubing
Conical top mount high flow filter
80mm HKS BOV
Fuel system - Twin Walboro 340 intake pump
C5 Fuel rail with return of rail
Boost referenced AFPR set at 50 psi base
60 lb Mototron injectors @ 48 psi
I think I got the important parts covered and I'd like to hear some opinions and if there is anything I omitted
dont crush that downpipe on anything and you wont have any pressure problems 
i run a 76mm w/ a 3" exhaust flange on a 366"
you will surpass your fueling set up before you will have any other problems.. if you keep it street you will likely start fighting the tune a lot too.
i run a 76mm w/ a 3" exhaust flange on a 366"
you will surpass your fueling set up before you will have any other problems.. if you keep it street you will likely start fighting the tune a lot too.
Thread Starter
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Joined: Nov 2001
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From: Toronto, Canada
Thanks MM,
The downpipe will be have to be ovaled for clearance. There is a local place that does it in my area
When they compress it they do it in a manner that changes the shape but retains the internal area.
The reason for the Front mount AFPR and boost referenced regulator is to help driveability (I hope) using a lower base pressure of 50 psi should allow the injectors to work at low rpm better and being boost sensitive pressure will increase with rpm. I'm hoping that it will help high rpm running. I have a return line off the rail that will allow for this.
As to the tuning I'm debating using a pull through MAF or tuning for speed density, I'm just not sure what will work best.
The downpipe will be have to be ovaled for clearance. There is a local place that does it in my area
When they compress it they do it in a manner that changes the shape but retains the internal area.The reason for the Front mount AFPR and boost referenced regulator is to help driveability (I hope) using a lower base pressure of 50 psi should allow the injectors to work at low rpm better and being boost sensitive pressure will increase with rpm. I'm hoping that it will help high rpm running. I have a return line off the rail that will allow for this.
As to the tuning I'm debating using a pull through MAF or tuning for speed density, I'm just not sure what will work best.
im not worried about your part throttle and idle, im talking about WOT
i'm assuming you are trying for over 1000rwhp.. the injectors wont cut it reguardless of pressure... neither will the pressure line.
unless you can get ahold of a 3 bar set up that works the stock computer your going to be fighting that too.
i'm assuming you are trying for over 1000rwhp.. the injectors wont cut it reguardless of pressure... neither will the pressure line.
unless you can get ahold of a 3 bar set up that works the stock computer your going to be fighting that too.
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Thread Starter
TECH Enthusiast
Joined: Nov 2001
Posts: 650
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From: Toronto, Canada
Not really sure I can even make 1000 with the computer and fuel system I have. In fact I am shooting for 750 + anything beyond that would be a bonus.
My thoughts and possible future plans would be an entirely new fuel system. I'd love to run dual injectors and a stand alone FMS.
I'm pretty sure the combination has the potential for 1000+ but that would most likely require some serious electronic and fuel mods.
My thoughts and possible future plans would be an entirely new fuel system. I'd love to run dual injectors and a stand alone FMS.
I'm pretty sure the combination has the potential for 1000+ but that would most likely require some serious electronic and fuel mods.
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Thread Starter
TECH Enthusiast
Joined: Nov 2001
Posts: 650
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From: Toronto, Canada
I have always pretty much known that the fuel system is my and most of our car's Achilles Heel.
I wish someone would come up with a creative inexpensive alternate to stand alone FMU's and exotic fuel delivery systems.
I wish someone would come up with a creative inexpensive alternate to stand alone FMU's and exotic fuel delivery systems.
think your pcm will be the main limiting factor as you run out of the MAF range.
why did you go with c5 fuel rails and not some billit FR? id get some of those that will probably help out some, im assuming you have at least a 10an feed line?
im sure its goinng to be a beast.
why did you go with c5 fuel rails and not some billit FR? id get some of those that will probably help out some, im assuming you have at least a 10an feed line?
im sure its goinng to be a beast.
Thread Starter
TECH Enthusiast
Joined: Nov 2001
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From: Toronto, Canada
The C5 rail has a return and a ready mounting point for the regulator without modification and has more than enough volume capability. I may go the billet route down the road. I am using a 10 an feed and return.
Ideally the best of both worlds would be dual injectors, smaller for idle and part throttle with another set to add lots of volume at WOT and racing conditions. I know my pump and fuel system can supply the needed volume, however the injectors are the biggest high impedence I can run for now.
I also just looked at the MegaSquirt, pretty cool but a little too much do it yourself for me at the moment. When I get it all sorted out this might be interesting, problem is, I don't need more complication at the moment.
Thanks for the link, I have book marked it
Ideally the best of both worlds would be dual injectors, smaller for idle and part throttle with another set to add lots of volume at WOT and racing conditions. I know my pump and fuel system can supply the needed volume, however the injectors are the biggest high impedence I can run for now.
I also just looked at the MegaSquirt, pretty cool but a little too much do it yourself for me at the moment. When I get it all sorted out this might be interesting, problem is, I don't need more complication at the moment.
Thanks for the link, I have book marked it
SSU'S Vice Mod
Joined: Jul 2004
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From: Hazard Co. Maryland
I'm doing some "early" research as I'm back and forth on what the final cubes will be on a project and on whether to buy a kit or build one, so, question stems, about your hot parts, is this a custom setup or is it one of the phamspeed header styles? TIA
Thread Starter
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Joined: Nov 2001
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From: Toronto, Canada
My kit is one of the original Phamspeed header style kits. The kit is great quality, however, in retrospect there are a few things I would change to make it even better.
That said I'm happy with the progress.
That said I'm happy with the progress.
SSU'S Vice Mod
Joined: Jul 2004
Posts: 2,391
Likes: 0
From: Hazard Co. Maryland
Originally Posted by Warbird
My kit is one of the original Phamspeed header style kits. The kit is great quality, however, in retrospect there are a few things I would change to make it even better.
That said I'm happy with the progress.
That said I'm happy with the progress.
What would you change Warbird? This is the direction I will eventually go (408 with an 88 @ somepoint) but the car that I'm planning on purchasing will more than likely go through a few iterations to get there. I'm not overly willing to give up my accessories, especially PS, I am willing to relocate things (radiator stood up, obviously alt.) that kind of thing and the more and more I think about things, I have a feeling if I fab I can save money. Obviously I don't want to spend money now only to have to rework something later in the quest of "more" when it can be done right the first time with the end result in mind. TIA for the input!