CA18DET & GT3076R

[NUT-CSE]

Just after some opinions on this.

My friend just got his car (Nissan Exa) back from the tuner after upgrading the turbo to a Garrett GT3076R, now the car made 262kw@w on 22psi but the problem i noticed is that it doesnt reach full boots till just after 6000rpm which to seems way to laggy. Now im just curious to know your opinions on what the problem might be? Ill also post up a pic of the engine bay and dyno sheet in afew days.

Engine specs are:

Forged pistons and rods270 / 8.8mm Tomei camsAdj cam gearsPorted head680cc injectors68mm throttle bodyCustom exhaust manifoldMatch ported CA intake manifoldFMICMicrotech LT-10 w Bosch CoilsGT3076R .82 turbineTial 38mm gate

[meminto]

Without knowing any other detail..

Personally I don't think that is too laggy for full boost on that particular turbo with the cam combination and turbine housing he is using...

I had a quick look at the comp map and it's a pretty good effort..

When does it start to make boost?

[NUT-CSE]

Well it starts to spool at around 4500 - 5000 rpm and full 22psi at 6000rpm and with a 8000rpm rev limit gives him only 2000rpm of a useable powerband.

I was looking at mobne's 497whp dyno clip on you tube with his GT35R and he makes 22psi at around 5200rpm? He spools about a 1000rpm earlier with a larger turbo?

[meminto]

Yep I reckon its the combination of the cams and turbine housing.. Without knowing any other ignition timing / fuel info

Ted has smaller duration cams, well last time I talked to him anyways lol and on that 497 run im sure they were 264s..

I forgot to add that from memory the turbo he was using had a smaller than .82 housing..

[bentvalves]

yea thats a poorly matched parts list.

before changing it all out and doing it all over again, tell your friend to try upgrading to some 1200cc fuel injectors, and run 2 or more bar on e85 or c16.

[r34 gtr]

I have looked at that turbo hard in the past, and I would have gone with the .72 or .64 housing if I was not running an alternative fuel. Try having him do what ks13 said, and if not have him buy a .64 turbine housing and try again. I think he can do much better.

[D_Stirls]

i would suggest setting up a solid head for the revs you are going to have to constantly pull to bring a GT3076 on song, that is if you are going to track your car. On the street a solid head probably isn't needed.

[boost_boy]

Switch to a .48 or .63 back housing. That .82 will cause you lag, but is good for the extra hp on the top end.

Dee

[NUT-CSE]

So his options are to either drop down to the 260' cams and get the smaller .63 turbine housing?

[meminto]

Out of curiosity, are his butterflies working?

I built a mates CA a little while ago and he is using 2871 with .86 housing, he had the buterflies removed (previous builder removed them) and complained about the lag from it..

He sourced another subplenum on my advice, and once the engine was back in and run in he couldn't believe how much of a difference in spool time working butterflies provided..

The build was basically a freshen up no extra parts added from what he already had..

[sjbsuperman1425]

Out of curiosity, are his butterflies working?

I built a mates CA a little while ago and he is using 2871 with .86 housing, he had the buterflies removed (previous builder removed them) and complained about the lag from it..already had..

the butterfly valves topic seems to be popping up alot right now, i wonder why?

[meminto]

coincidence i guess...

[D_Stirls]

Because there is a fair bit of evidence that they are worth keeping now. Hard figures evidence, not internet theorising.

[boost_boy]

Because there is a fair bit of evidence that they are worth keeping now. Hard figures evidence, not internet theorising.

Can't tell who you're referring to with the "internet theorising" comment, but one could say that these "hard figures evidence" you mention could be easily viewed as nothing more than just "figures". I feel meminto has went above and beyond to satisfy his quest for understanding the effects of the butterfly system on the CA18DET as well as going a step further by sharing the same info with the CA community. And if you agree that the testing he had done is sufficient enough to conclude that you guys will be using them for your applications, that's cool as they are your engines and you are free to do whatever you want with them.

Everything around here is debatable "Point Blank". Not everyone is going to get on your bandwagon because you found something that works for you or have found to work for the CA and this I know from experience. We collaborate here for knowledge and comparing of ideas as well as different applications on the beloved CA. I commend meminto for all his efforts on his project and his flow testing of the butterfly system, but he does his stuff the way he wants to and so do we. I personally don't care to have them around because (again) in the ranges that the computer actuates these valves, my engines is moving too fast to play with them. So after 13 years, I've decided to do away with them (my perogative).

Most people here in the U.S. don't use the butterfly system because of the amount of accessories you have to acquire to make them function correctly. And let me share a piece of old school info that might just deter you from using them or at least make you aware of what you're playing with and that's the fact the beloved butterfly vlave system has seals on it that seals vacuum from escaping your engine. If those seals fail from an intake backfire, 20+years of wear, petrol, carbon, heat, etc. , you will have major driveability issues and unfortunately for us in the U.S. , you can't buy those seals individually and nissan doesn't sell the butterfly plenum anymore. Just an FYi.

So in closing, debating this whole butterfly thing is cool, but in the end, folks will do what they want to and it would be unfair to consider whatever choice you make and/or decide to share with a group of enthusiasts "D_stirls", internet theorising. Remember, if it works for you, keep working it .

Dee

Modified by boost_boy at 3:49 PM 3/11/2010

Modified by boost_boy at 3:50 PM 3/11/2010
Modified by boost_boy at 9:37 PM 3/11/2010

[boost_boy]

Because there is a fair bit of evidence that they are worth keeping now. Hard figures evidence, not internet theorising.

And lastly, what was nissan thinking when they completely re-designed the intake plenum and head for the European CA motors? Just maybe (my hypothesis) they said it was too expensive to continue using that near worthless butterfly system on the turbo variants? Or was it because of emissions reasons??? Realistically, non of us really know why nissan didn't give the european CA18DETs some butterfly valves. That's why we experiment with this and that and ultimately comparing bench data against real-time experiences. Sounds like all of this stuff we all speak of is just internet gibberish, but we play the part collectively and some of us do learn a thing or two once we sift through the "internet theorising" .

Dee

[D_Stirls]

When you say the seals are failing are you talking about the valve stems seals that cause the intake valves in the butterflied runners to clog up with crap or are you talking about the seals on the shafts themselves.

If it is the former then that is an age thing and there is nothing you can do about it apart from replace the valve stem seals. If it is the latter then do what the SU and Webber blokes have been doing for a number of years get some brass and make up the bushes and seals. As these engines get older there are going to be less and less parts available and if you say that because you can't find a part off the shelf then you do away with the whole system then you'd better start playing with newer engines. Since i started playing with the CA i have found that there were a lot of parts that didn't exist (or exist any more) so i went to the shed and made them.

Now i have heard on here a number of times that since a 1.8 litre won't produce bucket loads of torque there is no point chasing torque and that you might as well do away with the measures that nissan put in place to increase the low down torque. If you have a drag car the go for your life but if you have a circuit car ot street car then this is madness because as Meminto's flow figures have show is that there is no real advantage in removing the butterflies until your pushing ~340 rwkw (520Bhp). So you are doing away with the increase in low down torque and gaining nothing (as most people on here aren't pushing 500bhp).

I hear what your saying in that you guys have trouble in getting all the parts needed to make then operate correctly but the gains that you will get are worth while looking around to try and come up with a way for controlling them if you don't have the full JDM setup. But all i hear for you is that there in ABSOLUTELY no point in keeping them, which isn't the case.

Advantages;

50% increase in low down torque (this is where a street car will spend 90% of it's time and it is were a circuit car will be pulling out of the corner.

With the butterflies working you have the ability to spool up bigger turbos earlier, so you can live with bigger turbos and reduced lag.

I get the feeling that you like the rush that you get from a big turbo ramping up which having the butterflies working will reduce the feeling of because it will produce a slightly more liner torque curve. It's all well and good that you like that feeling and that is a legitimate reason to build your car the way you have but when others are asking for your advice (which they should do, due to your experience) don't let that get in the way of disclosing all the facts and letting them make up their own mind.

[boost_boy]

When you say the seals are failing are you talking about the valve stems seals that cause the intake valves in the butterflied runners to clog up with crap or are you talking about the seals on the shafts themselves.

If it is the former then that is an age thing and there is nothing you can do about it apart from replace the valve stem seals. If it is the latter then do what the SU and Webber blokes have been doing for a number of years get some brass and make up the bushes and seals. As these engines get older there are going to be less and less parts available and if you say that because you can't find a part off the shelf then you do away with the whole system then you'd better start playing with newer engines. Since i started playing with the CA i have found that there were a lot of parts that didn't exist (or exist any more) so i went to the shed and made them.

Now i have heard on here a number of times that since a 1.8 litre won't produce bucket loads of torque there is no point chasing torque and that you might as well do away with the measures that nissan put in place to increase the low down torque. If you have a drag car the go for your life but if you have a circuit car ot street car then this is madness because as Meminto's flow figures have show is that there is no real advantage in removing the butterflies until your pushing ~340 rwkw (520Bhp). So you are doing away with the increase in low down torque and gaining nothing (as most people on here aren't pushing 500bhp).

I hear what your saying in that you guys have trouble in getting all the parts needed to make then operate correctly but the gains that you will get are worth while looking around to try and come up with a way for controlling them if you don't have the full JDM setup. But all i hear for you is that there in ABSOLUTELY no point in keeping them, which isn't the case.

Advantages;

50% increase in low down torque (this is where a street car will spend 90% of it's time and it is were a circuit car will be pulling out of the corner.

With the butterflies working you have the ability to spool up bigger turbos earlier, so you can live with bigger turbos and reduced lag.

I get the feeling that you like the rush that you get from a big turbo ramping up which having the butterflies working will reduce the feeling of because it will produce a slightly more liner torque curve. It's all well and good that you like that feeling and that is a legitimate reason to build your car the way you have but when others are asking for your advice (which they should do, due to your experience) don't let that get in the way of disclosing all the facts and letting them make up their own mind.

I hear you D and I made sure I read your post well, so I don't misinterpret your points. First of all, I was referring to the seals on shafts that run through the butterfly valve plenum. Those seals really get worn and these kids start screaming driveability issues and this is one of the little kept secrets that most don't know about. I've only had one that failed and that was back in 1998 when I was rocking the CA18DE in my car (no turbo). Back then, I experimented with the butterfly system and concluded that it is very much needed in the naturally aspirated engines. My CA18DE powered sentra was a lazy snail without the butterfly system properly connected and I will be lying if I said the butterfly valve system is completely useless.

Now on the turbo engine, it just didn't feel as effective as it did with the N/A motor because the little turbo was bringing the engine onto power so quickly, I guess I missed the effects. Maybe with bench testing, you can actually see the effects that butterfly valve have on air flow, but in my experiences, the engine experienced boost too fast to really feel the effects like I did when I was using the CA16DE and CA18DE engines respectively.

Now you feel nissan added the butterfly valve on the CA DOHC series to increase low rpm torque and I believe you are correct in that area, but I believe that it was cheaper for them not to re-structure an entire assembly line to delete what they thought was an effective system on their aspirated CAs to accomodate the turbo variants of the CA. I do believe european CAs or at least the heads and plenums were built on a different assembly line in which nissan thought it to be cheaper not too add the costly butterfly valve system because they felt they can reproduce the same torque created by the butterfly valve system by getting a tad bit more agressive with fuel and timing in the lower rpm ranges. I don't if the emission laws are strict or not in Europe, but if they are not, this would make a bit more sense.

Yes, I do use bigger turbochargers, but each car I have uses a different unit. I am fortunate to be able to play with many different turbo variations, but at the same time, all of that is useless if you cannot manipulate your fuel trim and ignition timing anytime you want to. Again, I am fortunate enough to be able to do my own tuning, so I make sure I get the most out of my off-boost driving by adding the necessary adjustments to make sure my car/engine is at it's most efficient in the lower rpm ranges. This subsequently allows the car to pull rather nice off boost which changes with a blip of the pedal.

I hope this discussion helps other members gain a better understanding of what they are messing with. Pay attention, but being advised to find your own road is "Priceless" .........

Dee
Modified by boost_boy at 12:12 PM 3/12/2010

[boost_boy]

So his options are to either drop down to the 260' cams and get the smaller .63 turbine housing?

What is his goal? A fwd car can benefit from .63 housing with that turbocharger if the tuner knows how to tune. With a .48, you'll be choking-off about 40-50hp, but the thing will be cocked and ready whenever he hits the gas pedal. As for the cams, keep them and focus more on the housing.

Dee
Modified by boost_boy at 12:05 PM 3/12/2010

[meminto]

A fair bit of discussion on this topic has been generated since last night lol..

I guess it will be one of things that will be a bane of contention, with arguments either side...

I think we can all agree on one thing:

Experience + Evidence = Better Informed Decision Making

On a whole I firmly believe it is a win for all of us

as a side note: I am working on some theoretical data at the moment (in between all my other commitments lol), that if successful, will be an interesting alternative to this..

[sjbsuperman1425]

damn you are always testing and trying new things for the CA. you seem like the designated CA investigator.

[float_6969]

The first thing I would suggest is dropping that turbine housing to AT LEAST the .64, and if it were my car, i'd drop it down to the .48, but mine's on the street a lot so I care about spool.

Secondly, from what I've seen on various other boards, the 260-ish cams seem to be the limit for a wide powerband on a CA18. When you jump up to the 270's, it just seems to make the motor really peaky.

I'm going to be running HKS 264's w/ 8.8mm lift and an HKS T4 top mount cast manifold w/ the T4 turbo that comes with the kit. HKS custom cast a turbine housing for that turbo to match the CA18, and it's a .48 housing. I'm still working on installing it, but from others that have run it, it spools pretty quickly for a straight T4 turbo.

[meminto]

lol, plenty of guys out there that do what i do passionate i guess...

I just get ideas and can't stop thinking about them till i get amongst it.. fail or success it doesn't matter to me as it feeds the learning..

[dash]

GT turbos r not the end all be all that many think they r.... LOTS of 'em plain suck.

I posted a link way back to a record settining 1.8L street miata that threw his gt3076 in the trash bin after trying a 50-trim t3/t4. Same turbo on several standout street miata 1.8s.Based on a few testiments by some nico CA18 users, I went with the same 50-trim

Mobne ran tomei 260/8.8s iirc

on the butterfly use.... some folks value midrange torque, T28s, quicker spooling turbos, etc..Then there r others who go for that "all or nothin" type powerbands. It is simple as that. Nothing to argue over. Bottom line; a boosted 1.8L can deliver either.Common perception view the flaps as a restriction..... but the fewfolks who have put forth the effort to actually test back & forth, have shown significant torque improvement throughout the most common used rpm range.Likewise, seen a megasquirted/ihi turbocharged toyota 4AG 'experiment' with his TVIS (same butterfly) to the point where he could only describe the result as "unnatural v8-like torque". Claimed a tremendous difference in daily drive & response, due to the broader torque band

don't the jdm 4g63 (cyclone?) and 3sgte also have butterflys ?

euro ca18s have a 0.64 turbine housing too.... vs the jdm 0.48, so torque must be the target

[blownhemi]

And lastly, what was nissan thinking when they completely re-designed the intake plenum and head for the European CA motors? Just maybe (my hypothesis) they said it was too expensive to continue using that near worthless butterfly system on the turbo variants? Or was it because of emissions reasons??? Realistically, non of us really know why nissan didn't give the european CA18DETs some butterfly valves. That's why we experiment with this and that and ultimately comparing bench data against real-time experiences. Sounds like all of this stuff we all speak of is just internet gibberish, but we play the part collectively and some of us do learn a thing or two once we sift through the "internet theorising" .

Dee

Someone had a really good flow of thought about this the other day: as the Euro ones also got the .63 A/R turbo, it was aimed towards more top end, probably for the """autobahn"""-s, versus the overcrowded streets and twisty mountain roads of Japan, where a .48 A/R, and some actual low-end performed better. I can't not agree with this one.I don't think it was about costs. They had the cheaper SR ready in '91, if they wanted to save on costs, they could have just given the Euro models the SR in '91 too, and dump this sorry excuse for an engine then and there, not wait until '94 for the S14 to do so.It also might have been emissions. Emissions are stricter here, than they are in California, and were probably even more so back in '89.

[boost_boy]

Someone had a really good flow of thought about this the other day: as the Euro ones also got the .63 A/R turbo, it was aimed towards more top end, probably for the """autobahn"""-s, versus the overcrowded streets and twisty mountain roads of Japan, where a .48 A/R, and some actual low-end performed better. I can't not agree with this one.I don't think it was about costs. They had the cheaper SR ready in '91, if they wanted to save on costs, they could have just given the Euro models the SR in '91 too, and dump this sorry excuse for an engine then and there, not wait until '94 for the S14 to do so.It also might have been emissions. Emissions are stricter here, than they are in California, and were probably even more so back in '89.

In 1989, Nissan was already in financial trouble which is why your beloved KA24 series became their bail-out engine as they just threw it in a bunch of different vehicles in many different markets. The KA was never meant to be a performance engine, but a compromise engine. Then came the introduction of the SR20. It was cheap, but hot and that's what they needed. Th CA was a ball-buster in production costs, so the european market dried-up the remaining CAs whilst the rest of the world got introduced to the new SR series. Steel costs, but that's a whole different subject that I hope you guys understand (China). The french jumped-in, spent some money on making nissan a power-house again and the rest is history.

I guess if nissan had some money, we would have enjoyed a CA20DET, but was blessed/cursed with the SR stuff, so it is what is.

Dee
Modified by boost_boy at 12:57 AM 3/13/2010

[D_Stirls]

At the end of the day i could be wrong and your right. Post up the factual evidence (Be it dyno graphs, time sheets, flow charts etc) that you have and we'll see. This is why i made the "internet theorising" comment as I haven't seen any evidence to a lot of the claims made on various forums when discussing the power valves setup.Where as i have dyno graphs and Matt has flow charts to back up what i was claiming.

Having said that if you have an aftermarket ECU or don't have the other hardware to make them work correctly then at the moment you have no other option but to remove then, but that is for functional reasons not performance.


Modified by D_Stirls at 3:50 PM 3/13/2010

[boost_boy]

At the end of the day i could be wrong and your right. Post up the factual evidence (Be it dyno graphs, time sheets, flow charts etc) that you have and we'll see. This is why i made the "internet theorising" comment as I haven't seen any evidence to a lot of the claims made on various forums when discussing the power valves setup.Where as i have dyno graphs and Matt has flow charts to back up what i was claiming.

Having said that if you have an aftermarket ECU or don't have the other hardware to make them work correctly then at the moment you have no other option but to remove then, but that is for functional reasons not performance.

Modified by D_Stirls at 3:50 PM 3/13/2010

Dude, don't even start asking me for some kind of graph for use of the power valve system. I've already given accolades to meminto for going the extra yard for said information, so I really am done with this topic. Read the posts and read them well. I too have once had the enjoyment of having a functioning power valve set-up, but times change and some things evolve or be evolved. This engine functions just fine without them and some folks prefer to have them in. Nissan also felt they didn't need them at some point either hence the creation of the european CAs. It's a choice and as stated before, it's a win-win whichever way you go. Again, I personally wouldn't waste my time trying to put this stuff back on my cars to provide a flow graph (Won't ever happen). I build engines in my spare time as well as tune, so I really done have the time to chase something as minute as this. I'm done with the clutter, so let's agree to disagree and keep it moving.

Dee

[float_6969]

I think the main reason the CA stayed in Europe for so long was due to the displacement based tax they had at the time. The 1.8L made the car more appealing to the masses over there as they had to pay less tax on it compared to a 2.0L.

I think the different head casting (4 port) and larger turbine housing were to accommodate the European's tendency to prefer vehicle geared towards high speed driving, and having less emphasis on low end torque and lots of stop and go driving and twisty roads. AFAIK, the European's NEVER got the 8 port head, at all, so they didn't just create it to use up the last of the CA blocks.

The power valves work, no question about it. But like ANYTHING engine related, there is a compromise. What you gain in low end and spool with the 8 port, you give up in total flow volume once the RPMS go up.

This is purely speculative, but I think if someone were to fabricate a TRUE 8 port manifold and INCLUDE the butterfly system, it would probably have the same top end power of the 4 port heads, but retain the low end torque of the 8 port setup. I think Nissan was close to hitting the mark on the 8 port idea, but just didn't have the resources (time & money) to see the concept all the way through.

[D_Stirls]

Quote »The power valves work, no question about it. But like ANYTHING engine related, there is a compromise. What you gain in low end and spool with the 8 port, you give up in total flow volume once the RPMS go up. [/quote]This is the thing though and the whole point of what i have been saying, the flow charts that Matt got from his builder show that there is Zero gain below 340rwkw (~500bhp).

[blownhemi]

I think the main reason the CA stayed in Europe for so long was due to the displacement based tax they had at the time. The 1.8L made the car more appealing to the masses over there as they had to pay less tax on it compared to a 2.0L.

I don't think that tax/insurance on an 1.8 vs a 2.0 would have been that strong of a selling point. There were quite a few other 2.0 contenders, Opel Calibras, Audis, BMWs, that sold well. They called it 200SX for a reason, and I think its because it was supposed to get a 2.0L engine from the get-to. Which one was that supposed to be, though, a real CA20DET that was scrapped because of its production costs, or an SR20DET that wasn't ready yet?

Maybe we should open a new thread for all this, we're getting completely off the original topic...