Manifolding/Minimizing lag

[hydra]

What are the power gains to be expected by going with aftermarket Intake and exhaust manifolds on a modded CA18DET? I'm going with a GT2860RS turbo and since the car is to be used for drifting/road racing I'd like to get the lowest possible boost threshold/lag. The cast iron exhaust manifold seems to flow reasonably well, and has the better thermal characteristics and a lower surface/volume ratio than any aftermarket offering. This should, in principle at least, give the best spool-up characteristics. How much power would I be giving up by sticking with the stock manifold? I would venture to guess not more than 2% i.e. not more than 6bhp on a 300bhp engine, can anybody provide any genuine hands-on feedback?

As for the intake manifold, most of the reviews I've read online have shown that a well-designed short-runner bellmouthed turbo intake manifold is good for a significant increase in top-end with only a mild reduction in mid-range torque. Again, any real-world reviews of these manifolds? Here's an example of the manifold in question: http://cgi.ebay.com/ebaymotors....m245

[r34 gtr]

You will notice a considerably shorter spool time with the stock manifold. Pretty much the reason everyone goes with the tubular steel one is because it is 500x easier to remove/install. I run the stock manifold and it suits my 2860R just fine.

That intake manifold is sexy as hell. Too bad it costs so damn much. I would totally rock that thing.

[The_Chosen_One]

For that kind of money I would rather go with the CPC intake manifold.

Tim I thought you were rocking the S15 GT28R?

[articzap]

Stay with stock exhaust manifold. Log style manifolds have the best spool times.

[hydra]

R34 GTR,That's precisely what I thought. At what rpm do you get 1bar of boost with your setup in say 3rd gear? The removal difficulty is a none-issue for me. I'll probably ceramic coat the manifold when the time comes to install my (already ceramic-coated) turbo.

About that intake manifold, I'm talking to the manufacturer about the possibility of setting up a group buy. So far it looks like we can get him down to the low-$400 range if there's enough interest. IMO this manifold looks better (from an aesthetic point of view at least) than the CPC manifold in addition to being significantly cheaper. While there don't seem to be any flow-#s published, this manifold has the same design-features as other "brand-name" manifolds with excellent published flow-distribution between the runners. And from eyeballing the pics, the runners look to have an overall length that correlates well with what my engine simulation program tells me is ideal for a CA18DET revving to 8000rpm...

[The_Chosen_One]

R34 GTR,That's precisely what I thought. At what rpm do you get 1bar of boost with your setup in say 3rd gear? The removal difficulty is a none-issue for me. I'll probably ceramic coat the manifold when the time comes to install my (already ceramic-coated) turbo.

About that intake manifold, I'm talking to the manufacturer about the possibility of setting up a group buy. So far it looks like we can get him down to the low-$400 range if there's enough interest. IMO this manifold looks better (from an aesthetic point of view at least) than the CPC manifold in addition to being significantly cheaper. While there don't seem to be any flow-#s published, this manifold has the same design-features as other "brand-name" manifolds with excellent published flow-distribution between the runners. And from eyeballing the pics, the runners look to have an overall length that correlates well with what my engine simulation program tells me is ideal for a CA18DET revving to 8000rpm...

Dont waste your time with Group Buy's we appreciate the gesture but CA members are pretty cheap. Im sure Boost Boy can tell you the wonderful experience he had with his Cam group buy.

Anyways just because something looks like brand name stuff does not mean its gonna perform like brand name stuff. If you're not making power than buying a IM wont do much. Money better spent will be in Head, Turbo, Tuning, etc etc.

[hydra]

It is a very common misconception that the IM is a flow "bottleneck" that should be one of the last things to be addressed. This has very little to do with flow, but rather tuning dynamics. Even if the runners are the exact same cross section as the stockers (which if I recall are on the generous side) power should greatly increase between 6500rpm-redline by mere virtue of the fact that the runners are so much shorter. This is what my engine simulation program says, and this is borne out by various dyno tests I have seen online. This of course assumes that your turbo is big enough to handle the additional massflow without going out of its efficiency range. There's no way to go significantly above a REAL 300bhp @ the crank on pump gas (below 20psi) with a GT28 without raising peak power rpm/volumetric efficiency; this means using a short-runner intake and some healthy cams... To tell you the truth I don't have much intuitive feel for why turbocharged engines respond so well to very short runner intakes (which are actually shorter than optimal for an equivalent N/A engine), and I suspect it has something to do with the compressor wheel not reflecting pressure pulses very effectively; whereas I understand the underlying principles well enough in N/A engines...

[The_Chosen_One]

I never stated it was a bottleneck I just stated that your money is better spent somewhere else. The OEM IM is perfectly fine for a good amount of HP. We've had people already do the research for our CA's.

Communist worked perfectly in simulation but failed in reality just a thought.

[boost_boy]

Dont waste your time with Group Buy's we appreciate the gesture but CA members are pretty cheap. Im sure Boost Boy can tell you the wonderful experience he had with his Cam group buy.

Anyways just because something looks like brand name stuff does not mean its gonna perform like brand name stuff. If you're not making power than buying a IM wont do much. Money better spent will be in Head, Turbo, Tuning, etc etc.

Cheapy-cheap indeed! Hey Hydra, go do your own thing and share your findings. With the CA, the open market is in and big name dealers and tuners are literally out on this platform. And a groupbuy around here for an intake manifold is pointless. Most folks are struggling to get their CAs to run successfully and consistently. Good luck on whatever you do, but please don't disturb the fish with the mentioning of a group buy.

Thanks,

Dee

[ser20det]

What about P&P the exhaust manifold ? And port match it with head exhaust port and gasket.

I'm curious about how much power we can give to a nice port and polish oem turbo manifold and how about turbo response.

[meminto]

Hydra, That inlet manifold is very well designed, I was skeptical until it arrived and both myself and engineer were extremely happy with it. There is absolutely no chance of this manifold being a restricition in flow for my build...

The materials used are of excellent quality, the welds are also excellent, unfortunatley there are no flow ratings advice by PNT_Performance, PNT have asked me to provide some flow performance results to them and I will provide this information as soon as my correct sized valvetrain arrives and its all back on the flowbench.

FWIW the stock inlet manifold flows max 220cfm, so if your head is not flowing above these numbers then there is no real advantage in replacing the inlet manifold.

I will provide flow info to PNT as soon as it comes to hand, I would assume they will provide this info to there customer base...
Modified by meminto at 2:51 AM 8/18/2008

[hydra]

Meminto,That's good to hear! By all means please share flow info with us as soon as you get ahold of it, thanks!

[hydra]

Meminto,Could you do me a small favor and measure the runner length and cross-sectional area of the ebay intake manifold for me? Could you also measure the stock (lower) intake manifold length for me as well? Much appreciated, thanks!

[float_6969]

You should talk to Ariel at CPC. IIRC he went through 3 or 4 different manifold changes before he got the CA manifold right. And this was all based on testing performed on the flow bench. His manifolds aren't just copied and sold. They have a lot of R&D that goes into them and they're tried and true.

When it comes time for an IM for me, CPC will be my only choice.

As far as the stock exhaust manifold, if I were going to do it again, I'd have the exhaust manifold and the turbine housing Extrude Honed as an assembly and then have it ceramic coated. The Extrude Hone process should yield equal flow through all of the runners and since the stock manifold is divided will greatly help to reduce reversion, something the SSAC mani's don't have. The ceramic coating will help to keep the exhaust energy in the exhaust and also help to increase the velocity of the exhaust.

I would be willing to bet that this combination would yield faster than stock spool up and a better than a tubular top end. Regardless, a completely stock manifold still spools the turbo about 500rpm faster than the SSAC mani does.

[jt15833]

stock mani isnt that bad to remove.

Top four and front bottom two nuts come off in about 2 minutes. the two rear bottom nuts are bishez however. 15 minutes maybe? tops, with jacking time. But i can jack very fast.

[meminto]

No worries, can do..

I am hoping to have it all back this week..

[bentvalves]

Extrude honing a stock manifold and turbine housing has been proven to work very well on an SR in this forum I believe.

Is an extrude hone something that can be done locally, i.e. phonebook, or something done specifically by one company?

as Meminto has suggested, intake manifold is only needed when you have a head/cam/turbo combo thats flowing high CFM's.

[hydra]

as Meminto has suggested, intake manifold is only needed when you have a head/cam/turbo combo thats flowing high CFM's.

That's precisely what I've been arguing against. Installing a short-runner intake manifold is supposed to show substantial gains once you hit the 300bhp mark on a CA. Just look at the profusion of aftermarket short-runner intake manifolds for turbo engines (CA18, SR20, RB2x, 2JZ, VAG 1.8T, 4G63, EJ2x, etc...) and you will see that they all share the same basic design. Check this link if you still need convincing, the results closely match what my engine simulation program used to give me: http://www.magnusmotorsports.c...m.htm

[float_6969]

Is an extrude hone something that can be done locally, i.e. phonebook, or something done specifically by one company?

It's a patented process that is done by one company.

[dash]

too many excellent performing CA18s run stock intake. Take a look at Mobnes 497hp beast for example. Even with relative mild 260 Tomei cams, stock intake manifold, stock nissan bearings.... he's right up there @11.2 sec 1/4s, alongside more co$$$tly builds (with short runner intakes).

If all this "intake theory" meant anything, would this be possible ?You can spend alot more and do no better.

[hydra]

Did a quick search but couldn't turn up anything so I must ask you this;How much boost was he running? Which turbo was he using ?At what rpm did he get peak power?

It is very much possible to get XXX bhp from a CA on the stock intake, but this doesn't necessarily mean that a) you're going to end up with a remotely reasonable torque curve, and b) you wouldn't have made even MORE power by switching to a short-runner intake. You know I could be very wrong about all this, in which case I'd be happy to eat humble pie, I would just like to see conclusive evidence...

[boost_boy]

Did a quick search but couldn't turn up anything so I must ask you this;How much boost was he running? Which turbo was he using ?At what rpm did he get peak power?

It is very much possible to get XXX bhp from a CA on the stock intake, but this doesn't necessarily mean that a) you're going to end up with a remotely reasonable torque curve, and b) you wouldn't have made even MORE power by switching to a short-runner intake. You know I could be very wrong about all this, in which case I'd be happy to eat humble pie, I would just like to see conclusive evidence...

I guess the ???? is why bother the intake manifold when it is not as restrictive as one may assume. I don't think most around here haven't the slightest idea of what 400whp out of the CA even feels like. But most start building this and buying that because of the name brands that produce said products and using the old theory that if "I spend a bunch of money on expensive parts, my car should be making x-amount of power" .

So I say to those that are interested in toying around with CA-bling, build one and test t he theories yourself. My results may not be to your liking which will then bring more questions. Each engine will produce different numbers due to too many different factors. I keep hearing this thing about lag, but most keep forgetting that the CA is a whopping 1809cc or 110 CID. How much CFM do you want this engine to flow? If you want anti-lag performance, get a bigger engine and a smaller turbo because the CA is going to lag when making big power and no intake or exhaust manifold is going to totally change that know fact.

You want to go faster? Efficient boost, fuel, and tuning is the key and until you've mastered it, well, at least blown engines can be rebuilt. In conclusion, one might be over-reacting about changing the intake manifold, but the exhaust manifold is up for discussion.

Dee

[dash]

if a short runner intake was better for tq all accross the rev band, couldn't OEMs have saved alot of money/material & no butterfly ?There is no free lunch and there will always be compromises.

I'd stay away from vendor/parts-pusher rhetoric. Its their job to convince & sell.Most of all, there are toooooo many proven CA18 setups out there to copy imo.Have u checked the big dyno/combinations thread sticky on sxoc ?You couldn't find a "remotely reasonable torque curve" amongst all those GT28 cars.... running stock intake ?

Mobne ran a rather big GT35? with 0.82 hotside iirc. Had probs higher, so he kept boost just under 2bar.

Tones old 20G setup perhaps my favorite 'street' ca18. Although engine dyno'd, still made 496hp and an extrordinary 474 ft-lbs tq. Stock intake.

[Vetal]

So is stock ex. manifold adequate for 350+ HP? Extrude honing won't be available here... BTW, how much power would it add at this level?

P.S. I gained 25whp (from 260 to ~285) by changing from SAAB FMIC to a good 3" one plus XSPower manifold

[Vetal]

Same question about intake. As I understood by reading gurus' comments, such manifold won't give me much even at 400+ HP?

P.S. Does anyone know how even is flow distribution between cylinders with stock intake manifold? I suspect #4 running much higher flow thus leading to #4 burning more frequently

[niscort]

Same question about intake. As I understood by reading gurus' comments, such manifold won't give me much even at 400+ HP?

P.S. Does anyone know how even is flow distribution between cylinders with stock intake manifold? I suspect #4 running much higher flow thus leading to #4 burning more frequently

lol... hoping to find someone here to back up your theory?

As I posted "elsewhere"... the flow testing done on the stock manifold by Ariel when doing r&d on his custom intakes produced data showing the 4 cyl being 6% down compared to 1,2 & 3 when tested @ 25"

[sjbsuperman1425]

from what it sounds like, the OE exhaust manifold is the way to go for quick spools and better response, with a ceramic coating and porting.

i did think of another alternative, that could be beneficial in two ways.

Ichiba makes an SR20 manifold similar to the Tomei Expreme Manifold. These manifold are NOT equal length manifolds and from the site below, says that it improves power and torque through all RPMs (atleast the Tomei one). Now since the OE CA exhaust manifold makes SR O2 housing hit the frame rail (in some cases), maybe buying the cheaper Ichiba Manifold and welding a flange from a CA manifold on it would be the greater of both worlds.

it would improve the power/torque in RPMs everyone wants and gives the clean, sexy, and easy working platform some desire.

http://www.frsport.com/Ichiba-....html

but of course, as stated by Boost Boy, CA owners are pretty cheap , and for $400, it might not be worth the hastle to buy a knock off equal length and the Ichiba model, then cut the flanges off and weld the knock off flange on the Ichiba. but its a thought.

anybody think the gains might be worth it..i think it could be for those sticking with the bottom mount platform?

http://www.jdm-option.com/eng/....html^^Tomei Expreme Testing

[Vetal]

lol... hoping to find someone here to back up your theory?

As I posted "elsewhere"... the flow testing done on the stock manifold by Ariel when doing r&d on his custom intakes produced data showing the 4 cyl being 6% down compared to 1,2 & 3 when tested @ 25"

Didn't I mention this is A.Bell theory? I apologize... The book is "Forced induction performance tuning", I really recommend it - very good read.

P.S. What is 25"?

[float_6969]

25" of vacuum.