Intake options
Thread Starter
Melting Slicks
Joined: Jan 2002
Posts: 2,238
Likes: 4
From: Milan
Intake options
I haven’t money to afford a Superram… so I’m evaluating some porting/polishing of the stock intake.
There are four elements:
Base manifold
Runners
Plenum.
Throttle body
What I need is to rev the engine without having this “wall� placed at about 4700/4800 rpm. As we know the engine is able to rev a bit over this “limit� but over this limit the torque curve is in a total irreversible downhill.
In order to minimize the the economical effort I’m asking you the parts that I can retain (and the modification I have to operate) and the parts I have to replace.
I think that the plenum and TB can be retained and I think the runners should be replaced (too thin to be ported). Edelbrock?, AS&M large tube runners, SLP?
Porting, Port matching, gaskets matching, siamesed runners, siamesed base, ported plenum, Ported throttle body… are all common terms.
Could someone be more specific on these expressions?
Example: What means porting the plenum? It means to enlarge the 4 right holes and the 4 left holes?
And what’s about the front hole (the one where the TB attacches to)?
Thanks
-Beppe-
There are four elements:
Base manifold
Runners
Plenum.
Throttle body
What I need is to rev the engine without having this “wall� placed at about 4700/4800 rpm. As we know the engine is able to rev a bit over this “limit� but over this limit the torque curve is in a total irreversible downhill.
In order to minimize the the economical effort I’m asking you the parts that I can retain (and the modification I have to operate) and the parts I have to replace.
I think that the plenum and TB can be retained and I think the runners should be replaced (too thin to be ported). Edelbrock?, AS&M large tube runners, SLP?
Porting, Port matching, gaskets matching, siamesed runners, siamesed base, ported plenum, Ported throttle body… are all common terms.
Could someone be more specific on these expressions?
Example: What means porting the plenum? It means to enlarge the 4 right holes and the 4 left holes?
And what’s about the front hole (the one where the TB attacches to)?
Thanks
-Beppe-
Race Director
Joined: Feb 2004
Posts: 12,517
Likes: 19
We have not been able to raise the useable rpm of an L-98 more than a few hundred rpm while still maintaing the stock length runner tubes. You can gain quite a bit of power by porting the lower manifold and upper plenum. Most will agree with this.My biggest regret is doing this and buying different runner tubes and having minimal gains for the money and time invested. "I" should have simply bought the super ram that I now have and am happy with. If labor is free I wiuld port and have fun with it. If you are going to invest serious money you may want to weigh your options(Super ram, mini ram, or that nice manifold Jesse and others run). I spent buckets of money trying runner tubes and throttle bodies. Just my $.02
Pro
Joined: Feb 2004
Posts: 641
Likes: 16
From: O'Fallon MO
I'm currently working on a spare manifold I aquired. Go to this link and get an idea of what it looks like.
http://www.geocities.com/jgkov/SiameseBase.html
No need for larger runners since with the Siamesed base the cylinder in each pair will draw air in from two runners at a time. Two standard runners have significantly more cross sectional area that one of the "big" runners, eg 2 std = 3.39 sq in vs 1 TPIS "big" = 2.16 sq in. The usual big mouth intake + big runners have one tube feed each cylinder instead of 2 at a time with the siamesed base. Saw somewhere where they have done this with the ZR-1's LT5.
check this out.
http://www.eecis.udel.edu/~davis/z28...age021105.html
http://www.eecis.udel.edu/~davis/z28...age010511.html
basically everyone whose done that tells you that youll loose some low rpm torque and gain a slight amount of high rpm breathing, there are BETTER OPTIONS for broader gains at both ends of the rpm spectrum withthe Super Ram and Mini-Rams but this seems like a cheap step to get some RPM with my new cam until I can afford to cough up another $1000+ for one of the name brand intake systems.
http://www.geocities.com/jgkov/SiameseBase.html
No need for larger runners since with the Siamesed base the cylinder in each pair will draw air in from two runners at a time. Two standard runners have significantly more cross sectional area that one of the "big" runners, eg 2 std = 3.39 sq in vs 1 TPIS "big" = 2.16 sq in. The usual big mouth intake + big runners have one tube feed each cylinder instead of 2 at a time with the siamesed base. Saw somewhere where they have done this with the ZR-1's LT5.
check this out.
http://www.eecis.udel.edu/~davis/z28...age021105.html
http://www.eecis.udel.edu/~davis/z28...age010511.html
basically everyone whose done that tells you that youll loose some low rpm torque and gain a slight amount of high rpm breathing, there are BETTER OPTIONS for broader gains at both ends of the rpm spectrum withthe Super Ram and Mini-Rams but this seems like a cheap step to get some RPM with my new cam until I can afford to cough up another $1000+ for one of the name brand intake systems.
Pro
Joined: Feb 2004
Posts: 641
Likes: 16
From: O'Fallon MO
Your question about the front of the Plenum. There is a big ridge running crossways at the bottom of the opening for the throttle body bores, grind that down so the air has a straight shot into the Plenum.
Team Owner
Joined: Jul 2004
Posts: 28,379
Likes: 3,262
From: Hartford WI
Originally Posted by Pete K
If you are going to invest serious money you may want to weigh your options(Super ram, mini ram, or that nice manifold Jesse and others run). I spent buckets of money trying runner tubes and throttle bodies. Just my $.02
Le Mans Master
Joined: Jul 2001
Posts: 8,183
Likes: 3
From: Santa Maria, CA
Originally Posted by aklim
Jesse who and what are they running?
"Ski_dwn_it" and "JBurnett". Jeb fabricated a plenum and put it on a single plane manifold. It's pretty much for humungo cube motors. They are at 434 cid right now.
Hey Beppe, did you ever fix the heater problem of heat all the time in your car?
If you siamese the base, you can go to 5200 RPM. No more.
Melting Slicks
Joined: Jan 2003
Posts: 2,167
Likes: 0
From: What did the 5 fingers say to the face? SLAP!!
Originally Posted by 89 Paul in Cal
Jesse is
"Ski_dwn_it" and "JBurnett". Jeb fabricated a plenum and put it on a single plane manifold. It's pretty much for humungo cube motors. They are at 434 cid right now.
"Ski_dwn_it" and "JBurnett". Jeb fabricated a plenum and put it on a single plane manifold. It's pretty much for humungo cube motors. They are at 434 cid right now.
You can rule out the single plane for a 350.
Thread Starter
Melting Slicks
Joined: Jan 2002
Posts: 2,238
Likes: 4
From: Milan
Originally Posted by 89 Paul in Cal
Hey Beppe, did you ever fix the heater problem of heat all the time in your car?
.
.
I found the fuse in the engine compartment and is still intact. I replaced in any case. NO results..
I go always with the thing UNPLUGGED to avoid this problem..
-Beppe-
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