Low End Torque on the Magnus Manifold

[dsmchiz]

I just had the pleasure of purchasing a Magnus Manifold with the velocity stacks. I have read a few posts on here regarding this manifold but these posts have been with guys that have 50 trim turbos. I only have a small 16g and i was wondering if my low end torque is going to be greatly affected by putting this manifold on over my stock manifold? This is a list of all my mods.


bolt ons:

Maf translator 3" GM Mas Air Sensor,
Small 16G turbo, ported by Forced Performance,
50mm tial bov,
Forced Performance ported exhman and O2 housing,
New '94 spec transmission,
Magnecor 8.5mm Wires,
Ported 2g exhaust manifold
3" Bud's custom "turbo-back" Exhaust (no cat),
Hallman Manual Boost controller at 15psi,
Wallbero 255,
APEXi Super AFC (Air Flow Control),
RC 550cc Fuel Injectors,
Buschur Front Mount Intercooler
Denso Radiator with 2 12" fans



Internals:

Block bored .5mm over,
Cylinders honed with torque plate,
'95 Pistons .5mm oversize,
ARP Head studs and rod bolts,
Balance shafts eliminated,
Bowl blend on intake valves,
Mild porting on intake and exhaust ports,
Intake valves backcut,
3 angle cut on valve seats,
Cylinder head de-burred,
Upgraded Valve Lifters,
Hks 264 cams AEM Cam Gears,
Hks valve springs


stuff getting installed this weekend:

Magnus Manifold w/ velocity stacks
Clutch Net 2600lb plate w/6puck clutch
AFPR with ss lines
New knock sensor

Any of you gentlemen that have this manifold or know of things about this manifold i would appreciate some advice
thanks in advance

chad

 

[16g-95gsx]

A test was performed on the various DSM manifolds and the 1g manifold outperformed them all from 4000-5700rpms, and above 6300rpms is where the SMIM's began overtaking the 1g heavily. With you only revving to likely the factory redline, the gains from a SMIM are going to be minimal. You will see a HP increase, which is generally the wow factor that causes everyone to get these things (minus the bling factor), but you will lose some low end torque. Its just the nature of the beast, a high revving manifold will lose you low end power. Personally I would imagine you would be better off with the factory manifold as far as area under the curve is concerned. If you were looking for an upgrade then I would suggest maybe try a Cyclone manifold if the magnus doesnt turn out the way you wanted it. The cyclone when controlled properly using an RPM based activation point will give you higher low end torque while still maintaining the 1g top end. Alot of people shun the cyclone because they:

1) dont have the equipment to properly activate it
2) See the SMIM's giving higher peak HP figures, not fully understanding that to get those higher figures they are losing low end power and revving higher

A manifold tuned for higher rpm VE will most definately make a solid amount more HP but always loses low end torque. The magnitude of this loss I can't say, but will definately be there.

 

[dsmchiz]

Thanks alot i appreciate the help. I think i will try it out and see i guess and if it does not work out i will see what i can do to change it. I do plan on going to the 57 trim soon but just have to have to money to get it yet.

 

[unlmtdndeavor]

based on what 16g-95gsx said about the smim making more power only above 5700rpm, you will still have 1300rpm for it to shine on the stock rev limiter. since you have cams you should be able to rev a bit higher and utilize that smim

 

[keymaster]

And with his motor setup, why would he only be revving to stock redline? He should at least be taking it up to about 8500.

 

[dsmchiz]

I dont think i will run that high of rpms. My ecu will not allow me to go past the stock rev limiter. If i am losing out on the low end torque but gaining on my top end hp i should still get a better 1/4 time than where i am at now correct?

 

[1993eclipseGS]

Did you ever install the Magnus SMIM? It's been a week since your last post.

 

[dsm-onster]

And with his motor setup, why would he only be revving to stock redline? He should at least be taking it up to about 8500.

With hks 264s? nope. It's fruitless.

To the original poster. . . Save it for an install w/ a set of 274s or better (and cheaper) FP2s, a 50 trim, 650s, and a chip to raise your rev limit.

 

[dsmchiz]

Yea i put it in. This weekend. It looks so nice . I also put in that fuel pressure regulator. I set the psi at 28 with the vaccum line off. I am pretty sure i did it right. Because I was supposed to set it at 43 but at idle the car is at -15 on the boost so 43 - 15 = 28. Now i cant seem to get my low fuel trims set on my logger at 1k and 2k my logger is at 140 percent on the low trim and i can add all i want to the afc with no affect. My wide band and volt meter for my o2 seem fine reading 14.2-15.4 on the wideband and bouncing around on the o2 all the way up to .82 at idle. I have not gone WOT yet cause i want to get the low trims set before i try to get the high trim. Do yall have any suggestions. I have read the post about tunning with the piggyback thats where i go my info about setting fuel trims but i cant seem to get it right. Now one thing i have noticed when i add quite a bit on the afc to try to compensate and get the fuel trims down then I turn the car off let it cool down and then start it back up it stuters real bad. Possibly cause of to much fuel cause when i pull some out of the afc I can hear the idle change and the wideband levels out instead of being incredibly rich.

Thanks for any info,

Chad

 

[1993eclipseGS]

Thanks. I need to order mine ASAP so I will be waiting to see if you noticed a difference.

 

[dsmchiz]

Sorry it took so long for me to post back up i have been very busy with work. But i installed the magnus manifold and the aeromative AFPR and after tunning alittle (bad gas so i am not running very much boost until i get water/alky injection) i am totally shocked. I really did not lose any low end torque. And before i had these parts on i would shift about 6200 rpms because the car just kinda flatened out on horse power. Now I nearly hit rev limiter every time (I dont pay attention to the tach just the way the car feels). The car pulls very very well from about 5000 rpms through redline (mine is stock 7200). I am very satisfied.

Now i just need to get better cams (fp2x), turbo (57 trim), injectors (720cc) and a better tuning device (prob AEM or Dsmlink) and i will be set.

 

[gmentals]

I set the psi at 28 with the vaccum line off. I am pretty sure i did it right. Because I was supposed to set it at 43 but at idle the car is at -15 on the boost so 43 - 15 = 28.

Its 1psi for roughly every 2" of vacuum(per VFAQ). So 15" vacuum is about 7-8psi. 43.5 - (7 or 8)=34 or 35

 

[Slippi84]

Its 1psi for roughly every 2" of vacuum(per VFAQ). So 15" vacuum is about 7-8psi. 43.5 - (7 or 8)=34 or 35

Yeah but that's for 2g's or injectors like FIC or delphi he has RC's and he's a 1g which stock fuel pressure is 34psi