Vortec L31 MARINE MANIFOLD project! Q&A

Performance modifications, tips & tricks

Moderators: flyingpolarbear, Eric@PPE, VicC, James B.

Speeder
Posts: 10772
Joined: Fri Apr 30, 1999 9:12 pm
Location: 2015 Tahoe 2WD 5.3L 6L80E, 2008 Colorado work beater, 2003 Dodge Dakota pro-touring project

Interesting...

Post by Speeder »

No velocity runners that the other guys are constantly saying are important for proper cylinder filling. Just a big open area over the intake holes for the heads.

Hog
Posts: 5036
Joined: Tue Dec 11, 2001 4:00 pm
Location: 1997 Chev ECSB L31 350 1997 GMC Sierra SLE RCSB, Ontario

post

Post by Hog »

postcleaning
Last edited by Hog on Thu Aug 18, 2005 11:02 am, edited 1 time in total.

rcfast
Posts: 280
Joined: Thu Mar 24, 2005 12:11 am

Post by rcfast »

Hey james what exactly did you get your fuel rails lookin so good? after lookin at mine it looks like i can get rid of the red with some laquer thinner. just wondering how you did it

White 350
Posts: 578
Joined: Fri Apr 03, 1998 8:12 pm
Location: Denver CO 2004 RCSB Z71 2011 Golf TDI

Post by White 350 »

I got my rails to look pretty much like Jame's rails. I ended up using a chemical paint remover in a spray can. This stuff worked like a charm. It made the paint soggy and it just slid off the stainless steel. Just don't get it on anything plastic like the little fuel test port cap. My cap is still red like James. I haven't figured out how to get the paint off of this yet!

rcfast
Posts: 280
Joined: Thu Mar 24, 2005 12:11 am

Post by rcfast »

White 350 wrote:I got my rails to look pretty much like Jame's rails. I ended up using a chemical paint remover in a spray can. This stuff worked like a charm. It made the paint soggy and it just slid off the stainless steel. Just don't get it on anything plastic like the little fuel test port cap. My cap is still red like James. I haven't figured out how to get the paint off of this yet!
that was another route i was thinking of, the red cap looks stylish :P

James B.
Moderator
Posts: 2823
Joined: Thu Apr 03, 1997 4:00 pm
Location: '98GMT400, '98GMT410, '99GMT420, '00GMT420

Post by James B. »

rcfast wrote:Hey james what exactly did you get your fuel rails lookin so good? after lookin at mine it looks like i can get rid of the red with some laquer thinner. just wondering how you did it
I used a chemical strip too. It's called "dad's" or something. Burns like hell on your skin. It didn't do well in the nooks and crannies. For that I used an Xacto knife. There's about 3 hours just on the fuel rail assembly alone.

Don't even bother trying to get paint off anything plastic, you'll just end up cussing. The only solution is to re-paint in desired color.

Pecos
Posts: 1103
Joined: Wed Mar 23, 2005 2:37 pm
Location: Minneapolis

Waste of time cleaning the red enamel off the plastic cap.

Post by Pecos »

Replacement plastic caps on the fuel rail test port, and replacement Schroeder valve in stainless steel (not brass as used on tire stems) can be found at any auto parts store for a dollar or two at the most. They are used on older GM vehicles for the air conditioner Freon fill port. They are the same parts. Same cap and Schroder valve. Bring your old parts to your local auto parts counter and ask to match them up for air conditioner service/replacement parts.
Last edited by Pecos on Fri Jun 02, 2006 7:32 am, edited 1 time in total.

NJCKZ71
Posts: 27
Joined: Fri Apr 03, 1998 8:12 pm
Location: Southern NJ

Post by NJCKZ71 »

Just got mine off the loading dock this morning. It will undoubtedly have a date with my buddy who mediablasts and applies industrial coatings for a living... I'll tank the stainless myself after disassembling. Not much time to study it yet in-person given I have the honest work to do...

Burban Boy
Posts: 189
Joined: Fri Apr 03, 1998 8:12 pm
Location: MN
Contact:

Post by Burban Boy »

Wow! this is very interesting... wish i had the time & $ to do this... Pecos let me know about it, but now im concentrating on the new car...

please post up when anyone has any updates on the install and performance!! im very excited to hear the results!!

GOOD LUCK guys!
Aj

Blown383 (Ken)
Posts: 367
Joined: Sun Apr 03, 2005 1:52 pm
Location: Southern CA 1997 GMC K1500 5.7L, Tog Headers, Cat Back, 3.73, FIPK K&N, JET DST

Post by Blown383 (Ken) »

For us Vortech SC guys how about modify a aftermarket intake manifold that would flow a ton more air than the stock setup? Either one would not be smog legal anyway...but it would be nice to have one that was :)

How much work needed to modifiy one of these for us vortech SC guys? I can see welding on some injector bosses and a plate on top for the TB....Tunercat programmer could delete the egr.

Image

GM Performance Parts Eliminator Vortec Intake ManifoldsMaximum power for Vortec heads. $319

Single plane GM Performance Parts' Eliminator Vortec intake manifolds mount a single high-flow 4-barrel with a runner and plenum configuration, fine-tuned to produce maximum power and torque from Vortec heads. An open "air-gap" space under the runners is engineered to reduce heat transfer to the intake charge, which helps to further maximize power.

Ken

rcfast
Posts: 280
Joined: Thu Mar 24, 2005 12:11 am

Post by rcfast »

I got my svo 30# injectors today, boy there way bigger than the 24 pounders.
Image
Image

Also im definately planning on repainting the manifold but to my suprise the paint on the inside of the manifold looks like its in perfect shape on mine so it doesn't look like anything needs to be done there. As far as the outside it looks like its powder coated because whatever is on there is really thick and seems smoother than paint would be. Im thinking of just cleaning the surface the way it is and scuffing it a little and painting over that. I think that would hold up just as well as sand blasting and primiring and repainting but at half the work. The only thing i could think of that might be a negative thing about this is making the manifold insulated more. anyone have any thoughts on this?

On a side note when im ready to install this thing its going to be fun for this thing weighs a ton. What do you guys think the stock manifold weighs? i would guess about 40 for the stock and 80 for this one. I still iffy on the whole iron lower, but the only downside i could find is just the weight and nothing else. Would there be any sort of other downside to the iron? just something i wondered, i couldn't find anything bad about using a iron intake other than weight.

burbman
Posts: 73
Joined: Tue Dec 11, 2001 4:00 pm
Location: Western Washington State

Post by burbman »

Blown383 (Ken) wrote:For us Vortech SC guys how about modify a aftermarket intake manifold that would flow a ton more air than the stock setup? Either one would not be smog legal anyway...but it would be nice to have one that was :)

How much work needed to modifiy one of these for us vortech SC guys? I can see welding on some injector bosses and a plate on top for the TB....Tunercat programmer could delete the egr.

Image

GM Performance Parts Eliminator Vortec Intake ManifoldsMaximum power for Vortec heads. $319

Single plane GM Performance Parts' Eliminator Vortec intake manifolds mount a single high-flow 4-barrel with a runner and plenum configuration, fine-tuned to produce maximum power and torque from Vortec heads. An open "air-gap" space under the runners is engineered to reduce heat transfer to the intake charge, which helps to further maximize power.

Ken
Ken, I have the Holley intake manifold that looks very similar to the one you pictured, which is set up for fuel rails and has injector bosses in place. This is the one that was sold with the Commander MPFI setup, I picked it up piece by piece. The setup is not yet installed, but very close (I work just a bit slower than you) I have come up with a way to use the stock CPI injector plug with the individual injectors, but will lose EGR. As far as I can tell, I will be able to retain all other functions.

Stealth97
Posts: 3711
Joined: Sat Jan 01, 2000 12:00 am
Location: 97 ECSB Chevy. 100% stock. LA, CA

Post by Stealth97 »

Why bother with the headache of getting injector bosses welded to a cast piece (not my favorite thing in the world to do exactly), when you can buy this piece for $349 base price or $550 acid ported and such.

Image

That picture is the #400-VMP the $550 ported version.

Image

That is the #400-VM $349 version.

Both are made by CFM Technologies.

website: http://www.cfm-tech.com/Catalog/chevy_s ... oducts.htm

Scroll to the bottom and you will find the FI manifolds. They can even install **GM Casting numbers**. Ultimate in smog legal streetability *wink wink*.

websites: http://www.cfm-tech.com/Catalog/ http://www.cfm-tech.com/


Yet, another route to go would be the one Speeder suggested. Holley Stealthram manifold. I saw this part advertised for sale at SDPC (scoggin dickey performance center) for $ 675.00. website: http://www.sdpc2000.com/catalog/741/pro ... g-page.htm

I think that is for standard SBC heads, but am unsure. If you have an L31 (Vortec) make sure you get the correct angle/bolt pattern manifold.

A picture of the manifold would be as so:

Image

Image

Ok, lets talk street legal. I get smogged every two, and they are strict enough here. I know people, but thats not enough anymore, so it doesn't concern.

I would think the Stealthram would sort of stick out more or less. Not sure if I could get it to pass visual legally (read: somewhere else). As long as it passed sniffer, I could get it by, but many others wont have this chance. I think the CFM-Tech manifold offers a different design, more or less like a stock (smog legal looking) manifold. The CFM-Tech manifold reminds me of the 50 state legal manifolds from Edelbrock, etc.

Any thoughts? Hope this helps. I can't decide which manifold to use. We have Marine, Holley Stealthram, CFM-tech, and then the FAST computer manifolds (what are those? can they be bought separate?)

My plan right now that I am currently working on is this: Dynotune truck to the maximum with stock motor, intake, headers, and get MY baseline. Post my dynosheet with a nice A/F curve, etc. Fully install Cfm-tech manifold (stockest looking one). By having to add fuel everywhere and adding to my VE tables, I will already know how much RWHP I gained (measured in airflow), but the dyno will be my proof. Again, I will post. Then I will try the Holley Stealthram. With three comparos of a stock motor, we should have a nice baseline to adjust to for each person using the manifold. I am doing this research purely for myself and my own maximum torque area under the curve, but I will share any information with my friends here at PPE. We may find one manifold better for lower HP, low end torque applications, and another for high HP vehicles. Subjective I would say. Driveability is another BIG factor. My truck must retain the stock feel, but double the HP output, and 1.5x the torque output (It can be done). Shooting for 500/500 at the rear wheels right now. (600/600 crank HP?). I think with this new tuning software, a good set of heads, a good manifold, and a little boost (1 bar), that is attainable.

Boosted-Z71
Posts: 1557
Joined: Thu Mar 24, 2005 6:38 pm

Post by Boosted-Z71 »

Stealth: Are there fuel rails available to work with the CFM manifolds? It would be very easy to make an TB or SC adapter to use on this manifold.

Boosted

PSWired
Posts: 3532
Joined: Tue Sep 18, 2001 9:12 pm
Location: Annapolis, MD 1995 GMC Yukon, 6L80e, E85 5.3

Post by PSWired »

Also keep in mind that edeljunk makes a manifold for the vortec smallblock that has EGR and is designed for their TBIâ„¢ to vortec conversion. It uses magneti marelli injectors that can be had from 19 thru 49 lb/hr.

Stealth97
Posts: 3711
Joined: Sat Jan 01, 2000 12:00 am
Location: 97 ECSB Chevy. 100% stock. LA, CA

Post by Stealth97 »

Boosted-Z71 wrote:Stealth: Are there fuel rails available to work with the CFM manifolds? It would be very easy to make an TB or SC adapter to use on this manifold.

Boosted
I don't have the answer to that question. It would most likely be custom. I'm wondering if a BBC fuel rail will be close in dimension and may work? I would need some measurements. Either that or maybe the LS1 fuel rail might be close as well. PSWired, do you have the dimensions of the LS1 fuel rail?

There are a lot of aftermarket fuel rails, but most are billet aluminum and are not cheap.

Maybe the GM marine SBC fuel rail will work? Can we get parts separately?

Lets see some other GM V8 fuel rails we might be able to use:

V8 camaro/vette rails. LT1 specifically. Anybody have dimensions for these?

James B.
Moderator
Posts: 2823
Joined: Thu Apr 03, 1997 4:00 pm
Location: '98GMT400, '98GMT410, '99GMT420, '00GMT420

Post by James B. »

See? It is exactly all these variables that made choosing the Marine L31 manifold seem the most logical.

Pecos
Posts: 1103
Joined: Wed Mar 23, 2005 2:37 pm
Location: Minneapolis

Cast iron is old school, yestertech, but quite functional..

Post by Pecos »

rcfast wrote:On a side note when im ready to install this thing its going to be fun for this thing weighs a ton. What do you guys think the stock manifold weighs? i would guess about 40 for the stock and 80 for this one. I still iffy on the whole iron lower, but the only downside i could find is just the weight and nothing else. Would there be any sort of other downside to the iron? just something i wondered, i couldn't find anything bad about using a iron intake other than weight.
Some of you might be too young to remember this, but for decades, intake manifolds were all cast iron. The down side of cast iron is weight, but HOG touched on an upside to this earlier in this thread. With the intake manifolds being the same cast iron as the heads means the expansion rate and expansion distance due to heat soak will more closely equal each other. This means less stress on the intake manifold gasket making it less prone to leakage.

John, to answer your question, I am fairly certain the red paint on these is basic marine enamel. Might possibly have used an epoxy like catalyst, but definitely not powder paint. Powder requires heat to melt the resin to get it to flow. Too much plastic on this thing to make powder work. I believe you could be safe using an etching primer on the enamel, then top coating it with any color you like. Heat transfer in cast iron is very slow compared to aluminium. I would not be concerned about altering any heat dissipation properties of the cast iron by adding a second coat of paint to the exterior. Just be aware that if the paint gets scratched, or flakes, the bright red enamel will shine through!!!

For anyone up to adding injector bosses to a non fuel injection manifold to create a custom FI manifold, here is an interesting drill bit to consider....

Image

http://www.msdignition.com/fuel_10.htm

As James mentioned above, fuel rails on a custom manifold are a signaficant challenge.
Last edited by Pecos on Fri Jun 02, 2006 7:36 am, edited 2 times in total.

rcfast
Posts: 280
Joined: Thu Mar 24, 2005 12:11 am

Post by rcfast »

I have another question. I removed the FPR assembly and i noticed the filter in it was pretty dirty. my question is how do you remove that filter? i want to clean it out for when i install it back in but i didn't want to start pryin on it and break it

Pecos
Posts: 1103
Joined: Wed Mar 23, 2005 2:37 pm
Location: Minneapolis

Healthy dousing from a spray can of ether (Starting Fluid)??

Post by Pecos »

The marine fuel pressure regulator (FPR) is believed to be standard GM issue. I remember Rob mentioned a while back he was working on identifying cross references for automotive equivalents for the FPR components. Maybe he, or someone else with access to GM parts catalogs (Taylor?) can chime in here, and possibly offer the automotive service proceedures for the filter too.

Post Reply