Why top mount?

[vectorsolid]

I searched around and found nobody had asked... So, here I am. What does the top mount manifold get you over something like a traditional Ram horn? This is pertinent, because I'm boosting my b16a, and making a final manifold decision. Sorry if it's a silly question.

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[jdmsiR20]

id like to say, thats its mostly for bling factor.

however, many will say that its possible to run huge downpipes with a top mount, as well as easier access to the actual turbo vs. a ram-horn

[DaveF]

Originally Posted by jdmsiR20

id like to say, thats its mostly for bling factor.

most definitly not.

[Schister66]

If you're going for all-out top end power and need to run a large downpipe, a topmount is the way to go. It also makes doing anything to the turbo much easier since it is more accessible.

If you're going for a street setup, then a topmount is not your best bet. Here is my topmount comparison....

Red is the topmount....Blue is my SLS shorty (current setup)-----both at 10psi
**Setup is the exact same other than the manifolds**

[boostincoupe]

The stunnA in me wants a topmount for the bling factor, but since I never plan on running a 4" downpipe or a GT42R I am fine with my ramhorn manifold.

[SPCBoyles]

Originally Posted by DaveF

most definitly not.

Okay, so it's most definately not just for bling factor...but you didn't really explain why. I was just about to post this thread, then I decided I should probably search before doing so. Very disappointed with the info and this thread is a month old! So, is there no definitive answer to the question, "which is better; top mount or ram horn"?

[Schister66]

As you progress through the different manifolds, each of them have their benefits and their downfalls. Picking the correct manifold is based on your individual needs for your setup...just because its "cool" to have a topmount, does not mean you "need" one on your stock block build.

Log < mini ram < ramhorn < topmount

Log
-The cheapest of all the manifolds. Log manifolds can easily be made to allow AC and power steering. A log manifold will spool up a turbo rather fast because of its short runner length, but due to it being less than ideal for high volume flow, top end power on a log can be greatly restricted. Logs such as the Inline Pro have a rather good design and ARE able to flow quite well at higher RPMs. A log will work perfectly fine for most street setups...especially stock block

Mini Ram
-Built with a 4-1 collector, mini rams flow better than a log and are still fairly compact and inexpensive. These manifolds are a good mix of short runner design (quick spool) and better flow at higher RPM. This is what i run on the street...i would recommend it for most people who DD their cars, but want better overall flow than a regular log manifold.

Ramhorn
- More equal length than the last two. Ramhorn manifolds have longer runners; therefore, taking longer to spool, but runners are closer to being equal length (better top end flow). Since these manifolds are bottom mounts, it is more difficult to fit a large diameter downpipe or easily manipulate the turbo.

Topmount
-The blingest of all manifolds apparently. A topmount is generally very close to, if not completely equal lenght meaning all runners are the same. This is important because of the cylinder exhaust pulses. Rather than overlapping in a non-eq manifold, in an equal length topmount, all exhaust pulses enter the turbo uniterrupted. This allows the most efficient use of exhaust energy without having deadspots created where there is no exhaust energy in the turbo...even if it is for just a millisecond. Topmounts are generally able to accomodate 4" downpipes and larger turbos due to the placement in the engine bay. For those of us who "need" a Borg Warner S372 under the hood, this is the ONLY choice.

Spool
1. Log
2. Mini Ram
3. Ramhorn
4. Topmount

Overall Power Potential
1. Topmount
2. Ramhorn
3. Mini Ram
4. Log

[mike@synapse motorsport]

i saw no difference in spool time and power production(600+whp) between my ramhorn and my top mount, maybe i just got lucky. if you need a 4" downpipe get the top mount, if not ramhorn will get the job done.

[SPCBoyles]

Thanks again Schister66, that was informative as always

[mrbsponge]

Originally Posted by mike@synapse motorsport

i saw no difference in spool time and power production(600+whp) between my ramhorn and my top mount, maybe i just got lucky. if you need a 4" downpipe get the top mount, if not ramhorn will get the job done.

correct, the topmount was designed for a 4inch downpipe with decent flow that didnt have to be hacked the hell up and bent in 120 degree angles to clear in the engine bay.

i saw no difference in spool time on my F-R topmount from my gt35R to my B/P S366 which is considerably larger and non BB

[200TS EC]

There was a huge in depth Post on this I searched and found once.

[SPCBoyles]

So, judging by what has been posted so far, it seems to me that top mount manifolds are theoretically advantageous when it comes to flow and performance. The only incontrovertible advantages to a top mount are the ease of access to the turbo charger itself and the ability to accommodate a large down pipe. If anyone disagrees, do they have any evidence to support their argument?

[Schister66]

topmounts are good for top end flow...they're not necessarily the best for the street unless you're making an unreasonable amount of power. I switched from a topmount to a mini ram and gained a lot of power throughout the midrange and even made a little more up top.

Here's my mini ram (blue) vs topmount (red)

[TheShodan]

Originally Posted by SPCBoyles

So, judging by what has been posted so far, it seems to me that top mount manifolds are theoretically advantageous when it comes to flow and performance. The only incontrovertible advantages to a top mount are the ease of access to the turbo charger itself and the ability to accommodate a large down pipe. If anyone disagrees, do they have any evidence to support their argument?

Be concise when you say "FLOW". There's a difference between VOLUME, and VELOCITY. Both terms deal with "FLOW", you mean CFM VOLUME when you mean flow based upon this statement. Too many people get a lot of these terms confused as to what "FLOWS MORE". It's not only inaccurate, but annoying.

This debate is about 2 years old. I know you're trying to get more of a serious consensus, but I don't think you want that "dog in the fight".

I doubt that people on this particular thread disagree on these statements, so now its your turn to go to the INDIVIDUAL people via PM, and find out what feedback matches YOUR particular needs.

[RCautoworks]

Originally Posted by DaveF

most definitly not.

Besides being able to fit a bigger downpipe in there easier, and the turbo is right there to work on... what else makes it better over say a ram horn ?

[SPCBoyles]

While I don't mind PMing individuals for their specific opinion on the topic at hand, I really enjoy the forum style discussion experience. I apologize for annoying you (TheShodan, and whomever else I may have annoyed), but I'm learning a lot from gathering more than just one opinion. I appreciate all the input from different sources. Thanks

[SPCBoyles]

Originally Posted by RCautoworks

Besides being able to fit a bigger downpipe in there easier, and the turbo is right there to work on... what else makes it better over say a ram horn ?

Originally Posted by SPCBoyles

...judging by what has been posted so far, it seems to me that top mount manifolds are theoretically advantageous...

[tony1]

Originally Posted by Schister66

topmounts are good for top end flow...they're not necessarily the best for the street unless you're making an unreasonable amount of power. I switched from a topmount to a mini ram and gained a lot of power throughout the midrange and even made a little more up top.

Here's my mini ram (blue) vs topmount (red)

I don't buy a manifold change making that much difference in spool. What turbo do you have that was making full boost at 6500 with the top mount? My 372 is making 40psi by then.

[Turbo-charged]

looks like they had a ripped coupler that they fixed when they swapped manifolds lol

[gogunkergorilla]

There are also equal length ramhorns. I'd stay away from top mounts if it wasn't for space or convenience.

[Mr. Danieli]

Not taking away from topmounts but I run an InlinePro T4 manifold on my car and it make 845 whp.And has gone a 9.47 and also has went 164mph in the Quater mile . So other things work and they dont cost an arm and a leg ! My manifold is half the price as any of the BIG NAME topmounts companies out there . You can spend the other half of your money on other parts. But this is just my 2 cents lol.

[RCautoworks]

Originally Posted by gogunkergorilla

There are also equal length ramhorns.

Got any pics ?

[Schister66]

Tony, i was disappointed with the slow spool on the topmount, but i assure you that i ONLY switched from a topmount to a SLS Shorty before that comparison. I dont think the spool times are very accurate on that dyno because my current setup spools at ~3800rpm on the street, but was spooling at 4600rpm on the dyno. I dont understand the large discrepensies...i'm just reporting what happened in my instance.

The turbo for both dynos was my GT3255b. The first manifold, the topmount, was a CoreyR topmount. My current manifold is the SLS shorty. Everything else in the setup was left as is....

[gogunkergorilla]

Peakboost has one. I've seen one before that looks more like a ramhorn but with runner 2 & 3 the same length as 1 & 4. If I can remember where I saw it I'll post it.

[SOHC_MShue]

Originally Posted by Schister66

Tony, i was disappointed with the slow spool on the topmount, but i assure you that i ONLY switched from a topmount to a SLS Shorty before that comparison. I dont think the spool times are very accurate on that dyno because my current setup spools at ~3800rpm on the street, but was spooling at 4600rpm on the dyno. I dont understand the large discrepensies...i'm just reporting what happened in my instance.

The turbo for both dynos was my GT3255b. The first manifold, the topmount, was a CoreyR topmount. My current manifold is the SLS shorty. Everything else in the setup was left as is....

was the topmount pull done in 3rd and the mini-ram pull done in 4th? I dont buy that much of a change in spoolup either. Something else had to be different.