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Discussion Starter #1
Based on my research it seems clear that ramhorn manifold seems to have better flow, but it has more places where it can crack. Cast Iron can be more durable but less air flow.

for my build I am looking for a good manifold that I can keep AC/PS. My goal is 350-450 whp. I will be running a GT2860RS Ball Bearing and the engine will be fully built.

I need some input on good manifolds whether cast iron or ramhorn. Please post what manifold you got and your whp numbers?
 

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Based on my research it seems clear that ramhorn manifold seems to have better flow, but it has more places where it can crack. Cast Iron can be more durable but less air flow.

for my build I am looking for a good manifold that I can keep AC/PS. My goal is 350-450 whp. I will be running a GT2860RS Ball Bearing and the engine will be fully built.

I need some input on good manifolds whether cast iron or ramhorn. Please post what manifold you got and your whp numbers?
Check out Go-Autoworks, they have a good quality ramhorn. The issue is usually the thickness and quality of the steel that is used, with cooling down/warming up, etc they tend to crack in time.

But you are correct, ramhorns do produce more efficienty exhaust velocity flow, which in turn more efficiently will rotate the turbine assembly in your turbo.
 

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A cast will work at those power levels, and don't use the term "fully built" as that is so broad and leaves a lot for interpretation.
 

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Discussion Starter #4
Check out Go-Autoworks, they have a good quality ramhorn. The issue is usually the thickness and quality of the steel that is used, with cooling down/warming up, etc they tend to crack in time.

But you are correct, ramhorns do produce more efficienty exhaust velocity flow, which in turn more efficiently will rotate the turbine assembly in your turbo.
Thank You sir
 

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Discussion Starter #5
A cast will work at those power levels, and don't use the term "fully built" as that is so broad and leaves a lot for interpretation.
here is what I mean by fully built, thanks for the answer

skunk2 Alpha rods
pistons - not sure. either wiseco or cp. I have read through a bunch of posts here of people using vitara. Does anyone know how much power they can handle?
supertech valve springs and retainers
ARP head studs
skunk2 cam gear
BC race cam stage 2
ACL race bearings
OEM Head Gasket
RC 1000cc injectors
walbro 255
Hondata S300
competition clutch stage either 4 or 5
 

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A quick Google search will answer all your questons. There is a guy right now making over 600 on vitara and it has lasted all season long. For 350 hp you don't need a built head, but will make things easier. For 450, things change a little. Pic a number not so broad and tells us what the car is used for. Being you want ac it sounds like a dd, and 350 is more than enough for the street, and your going to be hard pressed to get a Gt28 much over that power on pump gas
 

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GO-AUTOWORKS Turbo Kits Honda Civic Acura Integra D16 B16 B18

I have a customer's car using this with the turbonetics turbo good for 400hp. I see 7psi of positive boost pressure by 4000 rpms on a 9:1 p2p0/vitara setup using crower stage 2 cam. This will be the easiest and cheapest way to get to 350 whp. If you run e85, you can max this turbo out around the low 400's and still retain ac with minor block trimming
 

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I have used a log manifold and a self made ram horn. This is for my f22a but same principles apply except for the better f22a head and bigger engine.. Not much different but just don't expect for you to have spooling times with a gt3071r on a D. Maybe similar or better spool times with a gt28 on your D. But the ram horn started 1psi on my gt3071r at 2,600 rpms and hit 7psi at 3,100rpm in third gear. Hits 7psi in fourth at 3krpms. I did a lot of researching Into my designed ram horn. Its almost equal length +/- 0.5". And utilizes a step for anti reversion. And a few other things incorporated into the manifold. Spool up is only about 250rpms less than my cast log. Made 7psi 200rpms faster than my cast log. Top end pulls way harder. For the log it usually felt weaker at 6krpms with was about 500rpms after my max torque. But the ram horn keeps pulling and want to pull probably till 8k rpms.hope this helps. Ram horn was a good change over. Only cost me $150 to build it myself. Also something worth mentioning was on boost/ on boost throttle response is way better on my ram horn. Maybe it was those other designs I incorporated into it that helped out a lot. Merge collector angle was around 13 degrees. Some think 11 degrees is ideal but I didn't like how it would make the gas collide more before entering turbine. Didn't use 15 degrees because that's just too wide an angle and didn't want Exh gases not having a smooth transitioning flow.
 

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Oh crap never mind the spool times. U asked more about durability. But I'll leave this in case Smeone else see's this thread and wants to ask the log vs ram horn spool And lag comparison.
 

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I've seen lots of people and myself go with the mini ram. Good thing my flange was warped on my prototype mini ram so I never ran the mini ram, or else if I did I would have never made the ram horn. Some say go in between the RAM HORN and log and buy a mini ram. but if your a picky guy like me and precise details matter I'd go with smooth transition in Exh gas flow(merge collector angles, bends, and straight runners at certain spots) and exhaust pulse tuning which is equal lengthening the manifold, unless your twins scroll. Twin scroll is a more forgiving design due to only 2 banks colliding and not 4. Whatever design you choose make sure bends are NOT tight and unequal. It has to have a straight shot going into the merge collector. If buying a ram horn make sure 1&4 runners are higher at the most top 90° bend. If they are nicely even with 2&3 they are most likely NOT equal length. In theory a 2-3" of length difference between runners won't have too much an negative affecg,but to me it does
 

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If daily driven then go with a cast log. Spend the money on a better turbo, injectors, wastegate, etc. The H22 is the only engine that absolutely hates logs. D/B/F/K all work just fine with log manifolds - the trick is using the right one. The "tacotaco" d-series version, which is based off the b-series BLOX manifold, has great wastegate placement & has proven to make >460whp. It's also under $70!

If you have money to blow, get a ramhorn. It will make more power for a given boost level & set of parts, but this is only important if you're boosting a fragile stock block. With a cast manifold you just increase the boost til you're happy.
 

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But the ram horn started 1psi on my gt3071r at 2,600 rpms and hit 7psi at 3,100rpm in third gear. Hits 7psi in fourth at 3krpms. I did a lot of researching Into my designed ram horn. Its almost equal length +/- 0.5". And utilizes a step for anti reversion. And a few other things incorporated into the manifold. Spool up is only about 250rpms less than my cast log.
Wow, that makes me want to not only go with a gt3071r, but also that sort of ram horn.

FWIW, cast manifold with a T04E 60 trim here. 8 psi by 5,000 RPM on a D15B2/Y8. Yeah, real useful. I got the turbo for $20 and the manifold for $20 sooooo cool! OP, did you figure out what route you're going to take yet?
 

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I made 340whp pretty easily with a Ilovetacotaco cast ebay manifold. Just deburr and make sure its flat. Its cheap and never showed any signs of breaking.
 

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i have a taco taco cast manifold on a D15B7/Y8 head with a Garrett TB03 60trim off and old Thunderbird and I see boost at 2800 rpm and get all 11.5 psi by 4000 rpm. I was able to keep my AC with this manifold an run a 3" down pipe.
 

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Based on my research it seems clear that ramhorn manifold seems to have better flow, but it has more places where it can crack. Cast Iron can be more durable but less air flow.

for my build I am looking for a good manifold that I can keep AC/PS. My goal is 350-450 whp. I will be running a GT2860RS Ball Bearing and the engine will be fully built.

I need some input on good manifolds whether cast iron or ramhorn. Please post what manifold you got and your whp numbers?
Most cracking in manifolds is due to three things:

1) Use of cheaper grades of stainless steel like 304 in a thin wall

2) Improper welding (lack of penetration, setup, rod material, etc.)

3) Vibration & Movement (this is a big deal in a FWD car)

The fore and aft movement in conjunction with the exhaust swing puts a TON of force on the exhaust manifold. You need to run a flex joint somewhere and limit the movement of the engine and exhaust with firmer mounting.

Likewise, add reinforcement tabs from any bulkhead flange to the pipes and add load bearing brackets to take the weight of the turbo off the head mounting.
 
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