Best intake manifold for MY setup

[mrcivicsi2k]

I know the topic of intake manifolds has been discussed a 1000 times on here but i have done my research and i am still having troubles deciding. I have a 7 bolt with fp 2 cams and head studs, pte scm61 and all your basic supporting mods and my car is apart right now but i dont want anyone telling me to do a 6 bolt swap as that is coming but is out of the question right now. I could keep my 2nd gen im or i have access to a stock 1st gen im or a cyclone im or i could purchase a smim but keep in mind it will be for a 7 bolt head and if i can make nearly the same power with one of the im's i have access to ( stock, 1g, cyclone) then i dont want to spend the money on a smim just to have to sell it down the road when i switch to a 6 bolt also i do plan on changing to a 1g throttle body if i change from the stock 2g im. i do drive the car on the street but my only concern is making power at the track not in the daily driven part of it but i want something pretty simple to install and reliable but that makes good power.
thank you for any help i will be making my choice very soon so any quick responses from a knowledgeable person are greatly appreciated

 

[T9S1i]

if it were me and i was going to swap to a 6-bolt down the line to get the most out of that then i would just wait.

IMO just stay with stock for now, its made plenty of power in the past.
Mod once, mod right.

OR, you could get a SMIM now, 6-bolt swap your block and use your 2g head with the SMIM and the 6bolt bottom end.

 

[mrcivicsi2k]

i agree with everything you said but it wont cost me anything to switch to a cyclone or 1g manifold and there are plenty of local guys to sell a smim to when the time comes i actually already talked to a guy who said if i bought one and then switched he would buy it

 

[CanadianTSi]

Well a 1G or Cyclone on a 2g head isn't a good idea, so If you really want something then buy a SMIM and seel it later as you stated.

 

[mrcivicsi2k]

"Well a 1G or Cyclone on a 2g head isn't a good idea"

i dont have alot of knowledge on this topic so please explain this to me, i am not disagreeing just curious
thanks

 

[Boosted98gsx]

It depends on what kind of airflow you are planning on running at what point in the RPM band for which HEAD to go with:

If stock -> 20g ish range, port your 2g head and throw a 2g magnus on it.
if 20g - ~GT30ish 1g head and use a JM fab
if gargantuan, a properly ported 1g head with a SMIM (old school buschur style intake manifold)

I try to stear away from the Magnus as you are attempting to attain larger quantities of airflow as its design isn't the best for high RPM airflow. Tapered manifolds on forced induction is not a good idea.

 

[mrcivicsi2k]

i will be sticking with a stock 7 bolt head for now period! the question is simply which intake manifold to use as far as stick with my 2g intake manifold or switch to a 1g or cyclone manifold and 1g throttle body that i can get for free from a friend or buy smim but i only want to spend the money if it will be a significant increase in power.

 

[Boosted98gsx]

2g manifold, 1g throttlebody. Take off the manifold to port it, and ditch the EGR valve (via block off plate). A SMIM is DEFINATELY going to be worth the money in the long run, but not if you're planning on sticking with a 2g head (in other words, dont invest until you have a 1g head). Those ports will be the demise of that manifolds airflow.

 

[daren_p]

"Well a 1G or Cyclone on a 2g head isn't a good idea"

i dont have alot of knowledge on this topic so please explain this to me, i am not disagreeing just curious
thanks

He is saying this because the runners/ports on a 1g or Cyclone are much larger then the ports on a 2g head. If you bolt up one of those manifolds the air will basically be hitting a wall, creating turbulance. You could port the hell out of the 2g head to match but this isn't a good idea either. A good flowing head isn't just porting the hell out of it, its all about how the air flows & how it enters the valve. Hogging the 2g head out like this to match defently won't give you the best possible flow.

I would either stick with the 2g stocker till you do the 6 bolt if you are doing a complete swap or get a 2g SMIM and keep the 2g head on your 6 bolt swap. The 2g head may have smaller ports & won't flow as well stock for stock but the way a 2g head flows is better. It seems guys with drag cars are now switching to a properly ported 2g head vs the 1g.

 

[Boosted98gsx]

The 2g head may have smaller ports & won't flow as well stock for stock but the way a 2g head flows is better.

That is kinda conflicting dont you think? A 2g head flows better on smaller faster spooling turbos as it was designed for low end torque. A 2g head, ported, WILL outflow a 1g head, but a properly ported 1g head will outflow a ported 2g. For higher end airflow and power.

 

[mrcivicsi2k]

thanks for the great info and explanation guys

 

[90blacktsiawd]

That is kinda conflicting dont you think? A 2g head flows better on smaller faster spooling turbos as it was designed for low end torque. A 2g head, ported, WILL outflow a 1g head, but a properly ported 1g head will outflow a ported 2g. For higher end airflow and power.

No he's not contradicting himself. A 1g head is bigger from the factory and can accomodate more air in stock form. A 2g head has a much better design for flow than the 1g head.

 

[wishihadatalon]

That is kinda conflicting dont you think? A 2g head flows better on smaller faster spooling turbos as it was designed for low end torque. A 2g head, ported, WILL outflow a 1g head, but a properly ported 1g head will outflow a ported 2g. For higher end airflow and power.

A 2g head has much better port velocity which is far better than hogged out ports on a 1g head with the stupid 90 degree bend to enter the combustion chamber. Why do you think evo heads are so good? The have tall runners with a straight shot at the valve face and easy access to the cylinder. With a 2g head you have more tq and a head that is capable of making well over 600whp with 0 porting. There is a reason mitsu switched to that design but the only problem is the smaller profile cams and crappy intake manifold on a 2g

 

[daren_p]

That is kinda conflicting dont you think? A 2g head flows better on smaller faster spooling turbos as it was designed for low end torque. A 2g head, ported, WILL outflow a 1g head, but a properly ported 1g head will outflow a ported 2g. For higher end airflow and power.

Conflicting no, but I think I used the wrong word what I should have typed:

The 2g head may have smaller ports & won't flow as much stock for stock (compared to a 1g setup) but the way a 2g head flows is better

 

[qtxdevilz]

buy a sheet metal intake mani for the 2g head...then when you do the 6 bolt swap...use the 2g head on your 6 bolt bottom end...all you have to do is drill out of head stud holes 1mm bigger...that way you can continue to use the 2g head with the intake mani...so 1 you get to use sheet metal intake mani now and 2 you have a 2g head which flows better when ported out for later on...

 

[CanadianTSi]

Bigger isn't always better...

The smaller ports on the 2G head keep air velocity up, which is a good thing.

My magnus IM works great on my 50 trim setup...added maybe 200 rpms to spool up but it pulls hard all the way up top.

 

[Boosted98gsx]

A 2g head has much better port velocity which is far better than hogged out ports on a 1g head with the stupid 90 degree bend to enter the combustion chamber. Why do you think evo heads are so good? The have tall runners with a straight shot at the valve face and easy access to the cylinder. With a 2g head you have more tq and a head that is capable of making well over 600whp with 0 porting. There is a reason mitsu switched to that design but the only problem is the smaller profile cams and crappy intake manifold on a 2g

That was my point...

The way he said that the 1g "flows more" but the way a 2g head flows is better, is a contradicting statement. Power is a direct equation as to how much air and how much fuel you can get into the chamber (air being the obvious hard part). The 2g head and it's increased velocity WILL FLOW MORE than a 1g head in the lower rpms due to this. Because the 1g head has that 90* bend down into the valves, it's FLOW is restricted.

Flow is simply flow. If the WAY something flows is better, it's going to flow better, very simple. The 2g head will FLOW better with a 14b than a 1g head would with a 14b (if you emliminate the intake manifold restriction of the 2g).

 

[nanokpsi]

Simple solution to this. Do like I did and just buy a used 2g SMIM. That way you can turn around and sell it for close to or exactly what you paid for it. I knew all along I would be going with a heavily ported Polk 1g head. When I put the pt67 on the stock longblock, it was so laggy that I needed more top end flow. I think the whole ordeal cost me about 40-60 bucks, but it surely made a bunch of power. Just food for thought

To all of the people who argue about the 1g vs the 2g head, Just remeber Shep runs a 1g head with a little Polk magic as well

 

[wishihadatalon]

Simple solution to this. Do like I did and just buy a used 2g SMIM. That way you can turn around and sell it for close to or exactly what you paid for it. I knew all along I would be going with a heavily ported Polk 1g head. When I put the pt67 on the stock longblock, it was so laggy that I needed more top end flow. I think the whole ordeal cost me about 40-60 bucks, but it surely made a bunch of power. Just food for thought

To all of the people who argue about the 1g vs the 2g head, Just remeber Shep runs a 1g head with a little Polk magic as well

I am not going to clutter this thread but comparing sheps car to anything any of us will ever build is pointless.

 

[nanokpsi]

I am not going to clutter this thread but comparing sheps car to anything any of us will ever build is pointless.

Well, stock vs stock cars see a flow increase by moving to the 1g stuff. I figured most people knew that already. Some people believe that there is more material to remove on the 2g heads so they have the potential to flow more max effort wise. That is why I brought up Shep.

As for the manifold, I used to never want ot buy used stuff. My good friend was a used parts whore. After I saw him saving good money and getting quality stuff, I figured I wouldn't miss out any longer. I sold my used 2g magnus for around 400 IIRC. I'm sure you can find somehting along those lines.

 

[krnbk2]

If you end up getting a SMIM, Id recommend JM Fab. Super quality manifold at a great price.

Heres a pic of mine with optional Nitrous bungs and polishing:

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[wishihadatalon]

Well, stock vs stock cars see a flow increase by moving to the 1g stuff. I figured most people knew that already. Some people believe that there is more material to remove on the 2g heads so they have the potential to flow more max effort wise. That is why I brought up Shep.

As for the manifold, I used to never want ot buy used stuff. My good friend was a used parts whore. After I saw him saving good money and getting quality stuff, I figured I wouldn't miss out any longer. I sold my used 2g magnus for around 400 IIRC. I'm sure you can find somehting along those lines.

The power increase is from the better intake manifold design and the cam profiles. With a 2g head you would have a better all around car. And yes there is more material to remove but you have to think different. Think up (way past the injector bungs) and stay away from the floor of the port and you get into some crazy stuff.

 

[Turbocharged]

Both the 1g and 2g heads are very nice designs. Either head can make plenty of power, ported or not. I'll stick with my 1g head because I know that its capable of flowing enough to make 500hp. I didn't even bother with heavy porting, I just cleaned up the bowls and smoothed out any casting flaws.

Does anyone have before and after dynos on high horsepower DSM after swapping to a SMIM? I've only seen a comparison on a 16g powered car.

 

[nanokpsi]

The power increase is from the better intake manifold design and the cam profiles. With a 2g head you would have a better all around car. And yes there is more material to remove but you have to think different. Think up (way past the injector bungs) and stay away from the floor of the port and you get into some crazy stuff.

On the cars I have seen/done head swaps the owner already had a set of aftermarket cams. so the flow increases aren't the cams (as the 1gs are slightly more agreessive). Also, flow increses tend to be about the same when upgradeing either head/manfiold with a SMIM (typically 4-5 lb/min increases regardles if it is a 1g head car or 2g). Since the gains over the stock part are similar it leads me to believe the flaws in the stock manifolds are similar.
I wish I was in the postion to have personal experiece with a high port 2g head. I don't have the budget to buy a fully done up 1g and 2g heads to see which one yields more power.

 

[90blacktsiawd]

Nanok i'm confused about something you just said. The flow increases aren't from the cams? With more aggresive cams the valves open higher and longer, so how is it the cams wouldn't add airflow? Personally it seems foolish to do a SMIM before doing cams. It can be done but the stock cams in our cars aren't meant for the higher rpm's that a SMIM will shine at.