Siamese or Superram? pros n cons
Thread Starter
Burning Brakes
Joined: Feb 2000
Posts: 1,247
Likes: 2
From: Parker, Colorado, USofA
Siamese or Superram? pros n cons
I'm building a 383 this winter (Scat crank, forged pistons, 10.5:1, TPIS base manifold, LPE 219 cam) and am looking at the top of the motor now.
The question is:
Siamese runners are about $250. Ported to the stock air plenum will do good things for reducing runner length and improving flow.
A Superram costs about $1200 (or less used). It's supposed to have improved HP and torque over the siamese runners, but I can't get any kind of qualitative numbers. It's a grand worth of motor budget, it's a PITA to install, and it thoroughly covers up everything on the top of the motor.
It sure looks cool though. :lol:
In any event, I'm replacing the manifold base, which is the REAL bottleneck, I'm just wondering what the incrimental improvements would be between the rest of the top end. This is for a street car useage, that'll see some medium speed roadracing and low speed autocrossing. It's also an automatic convertible, so I'm not HONESTLY expecting it to be the best racer out there, just as fast as anything on the street with street tires . :cool:
The question is:
Siamese runners are about $250. Ported to the stock air plenum will do good things for reducing runner length and improving flow.
A Superram costs about $1200 (or less used). It's supposed to have improved HP and torque over the siamese runners, but I can't get any kind of qualitative numbers. It's a grand worth of motor budget, it's a PITA to install, and it thoroughly covers up everything on the top of the motor.
It sure looks cool though. :lol:
In any event, I'm replacing the manifold base, which is the REAL bottleneck, I'm just wondering what the incrimental improvements would be between the rest of the top end. This is for a street car useage, that'll see some medium speed roadracing and low speed autocrossing. It's also an automatic convertible, so I'm not HONESTLY expecting it to be the best racer out there, just as fast as anything on the street with street tires . :cool:
Le Mans Master
Joined: Feb 1999
Posts: 6,172
Likes: 11
From: somers, ny
Re: Siamese or Superram? pros n cons (RocketSled)
In one of TPIS's books (i think it is the first one), they do a comparo of the stock runners, siamesed runners and superram. Below is the torque curves from a 383...you can convert to HP yourself. I have not seen too many examples of successful combos using siamesed runners. maybe cause they don't agressively market them or maybe because they don't work too good...i dunno. A proven combo is the superram with good heads and 219 cam. Good luck
Torque SR run Siam
3500 434 486 452
3750 447 500 469
4000 458 499 468
4250 458 480 475
4500 457 463 469
4750 460 440 454
5000 452 414 442
5250 438 399 429
5500 429 391 408
5750 406 383 398
6000 378 365 365
Avg 438 438 439
Torque SR run Siam
3500 434 486 452
3750 447 500 469
4000 458 499 468
4250 458 480 475
4500 457 463 469
4750 460 440 454
5000 452 414 442
5250 438 399 429
5500 429 391 408
5750 406 383 398
6000 378 365 365
Avg 438 438 439
Le Mans Master
Joined: Aug 2000
Posts: 7,760
Likes: 0
From: Lost in the mountains of TN
Re: Siamese or Superram? pros n cons (RocketSled)
I'm building a 383 this winter (Scat crank, forged pistons, 10.5:1, TPIS base manifold, LPE 219 cam) and am looking at the top of the motor now.
Race Director
Joined: Aug 2000
Posts: 14,130
Likes: 7
Cruise-In II Veteran
Re: Siamese or Superram? pros n cons (BiZ)
The SR seems to be the obvious choice...it was designed just for the applications with their matched cams.
However, its not cheap in terms of engine building and all the other costs involved.
The SLP siamese runners are in need of alot of port work.I have them and their openings are no bigger than stock.The siamese ports go back very little, hard to believe just cutting them back supposedly gives 18 HP and Tq on a stock or modified engine.
If you get SLP for now, and save for the SR later, get large tube runner gaskets and port match the SLP runners to that size and cut back the siamese wall back a little further.Siamese the plenum openings too.
That should be able to flow the air youre going to need for your new engine.I just dont see it working ot of the box to flow on alot of engine mods.
I have a web page with the SLP's ported a little bit..I have done alot more then what you can see there but havent made any more pics.
To get an idea of the opening sizes and to see them stock and then ported to large tube gaskets sized,go to:
http://community.webtv.net/TunePort28/
Youll see there how small their ports are compared to large tubes.
Good Luck..and believe me, everyone WILL prob. tell you the SR is the way to go.
See JD383's SR engine...that thing hauls!!
However, its not cheap in terms of engine building and all the other costs involved.
The SLP siamese runners are in need of alot of port work.I have them and their openings are no bigger than stock.The siamese ports go back very little, hard to believe just cutting them back supposedly gives 18 HP and Tq on a stock or modified engine.
If you get SLP for now, and save for the SR later, get large tube runner gaskets and port match the SLP runners to that size and cut back the siamese wall back a little further.Siamese the plenum openings too.
That should be able to flow the air youre going to need for your new engine.I just dont see it working ot of the box to flow on alot of engine mods.
I have a web page with the SLP's ported a little bit..I have done alot more then what you can see there but havent made any more pics.
To get an idea of the opening sizes and to see them stock and then ported to large tube gaskets sized,go to:
http://community.webtv.net/TunePort28/
Youll see there how small their ports are compared to large tubes.
Good Luck..and believe me, everyone WILL prob. tell you the SR is the way to go.
See JD383's SR engine...that thing hauls!!
Pro
Joined: May 1999
Posts: 634
Likes: 0
From: milford,Ma. USA
Re: Siamese or Superram? pros n cons (RocketSled)
If you really want to stay with stock looking set-up the only runner to consider is the AS&M runners. My friend just dynoed 325 rwhp with them, along with trick flo heads, 219/219 cam, big base, and linenfelter long tube headers, this is on a 350ci engine.
Racer
Joined: May 2001
Posts: 452
Likes: 0
From: Griffin GA
Re: Siamese or Superram? pros n cons (RocketSled)
With a 383 go with the super ram. Porting stil will not pull enough air. If you have not already done so you will also need to increase the size of your exaust. Also think about new heads and headers.
I,m using the ported with LPE runners and manifold, Stayin
I,m using the ported with LPE runners and manifold, Stayin
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Pro
Joined: Jan 2001
Posts: 602
Likes: 0
From: Aliso Viejo CA
Re: Siamese or Superram? pros n cons (RocketSled)
The other thing is that you have the wrong price. The $1200 includes the base. The superram runners and plenum alone are *only* $799 through lingenfelter directly. Can get it cheaper elsewhere.
Safety Car
Joined: Dec 2000
Posts: 3,767
Likes: 5
From: Jacksonville Fl
Re: Siamese or Superram? pros n cons (Warlock)
I think the base is the biggest HP thing in the whole SR deal.
I am guessing that no one uses the large base with siamesed runners and a ported upper plenum. I think I will go that way on mine.
I am guessing that no one uses the large base with siamesed runners and a ported upper plenum. I think I will go that way on mine.
Burning Brakes
Joined: Oct 2000
Posts: 1,241
Likes: 0
From: phila. pa .usa
Re: Siamese or Superram? pros n cons (Bill's86Coupe)
Bill, I just replaced manifold to accel&24svo inject., tried puttin on slp runners after cuttin plenum(siamese), driversside runner hits #7 cyl. inject., not enough space how did u get around this, now I have hesitation& backfire when pullin away any ideas?? :(
Race Director
Joined: Aug 2000
Posts: 14,130
Likes: 7
Cruise-In II Veteran
Re: Siamese or Superram? pros n cons (88sk)
88Sk,
Not sure whats wrong with your application.
Its possib you have to re set the minimum air speed and TPS settings because you just opened up the entire intake uite a bit.
You may also have vacuum leaks somewhere...you will need to be sure you dont have any along the runners and gaskets.
If the 88 stil uses the cold start valve,see if the CS valve is pressed in all the way.
I had a vacuum leak here with the SLP runners..the CS valve hole isnt large enough to let the CS valve sit in all the way...the runner more ore less is too thick there.
I had to grind away the side of the CS hole and runners a little bit to allow it to fit.
A vacuum leak there is a PITA to find.
Get some carb spray and go look for vacuum leaks and listen for hissing noises.
Be sure your PCV system is reconnected..I know the runners are too big to let the PCV pipes and etc fit under them and etc so you need to re route them for clearance or cut your own hose to length etc.
Hope this helps some.
Not sure whats wrong with your application.
Its possib you have to re set the minimum air speed and TPS settings because you just opened up the entire intake uite a bit.
You may also have vacuum leaks somewhere...you will need to be sure you dont have any along the runners and gaskets.
If the 88 stil uses the cold start valve,see if the CS valve is pressed in all the way.
I had a vacuum leak here with the SLP runners..the CS valve hole isnt large enough to let the CS valve sit in all the way...the runner more ore less is too thick there.
I had to grind away the side of the CS hole and runners a little bit to allow it to fit.
A vacuum leak there is a PITA to find.
Get some carb spray and go look for vacuum leaks and listen for hissing noises.
Be sure your PCV system is reconnected..I know the runners are too big to let the PCV pipes and etc fit under them and etc so you need to re route them for clearance or cut your own hose to length etc.
Hope this helps some.
Burning Brakes
Joined: Oct 2000
Posts: 1,241
Likes: 0
From: phila. pa .usa
Re: Siamese or Superram? pros n cons (Bill's86Coupe)
thanks bill,will check for leaks& check timing&tps setting(.54-.65), I had to put stock runners back on because injector& runner(driversside)cant occupy same space at once, did u have this problem???
