Figured out a new turbo Monster.

[jeffp]

That sounds like good advice to me. Clark is very knowledgable in this area. I did ask one time what the compressor was and I keep thinking a 50 was stamped on the compressor housing, but I could be wrong. I got their turbo and it has run very well for me and I dont think I will have any problems with it, but I need to watch the boost levels and stay in the 20psi range with it as the higher levels tend to want to make the seal leak in short order, relatively speaking.

The thing with the JWT system is that htey havenot developed a 600Hp 280 system, a sport 500 is the biggest, and then all that is done is a swap out of the .64 A/R garrett housing for the Ford housing with the .82 A/R and that bumps up the power to the 500Hp and I would be willing to bet that 500 is exactly what the thing will do.

I am still in the design consideration stage in the game, really what I am waiting on it ifthe system will run 600Hp or do I need to go with an after market system to get me to 600Hp. All of your input has been very beneficial to me and has given me somethings to consider. I will see if I can get the specs of the turbo.

[SHANE]

FWIW the company i posted of above(TEC) use to do ALL of JWT turbos. i dont know if they still do, but i could try to find some more info on your turbo for you (if it is in fact a TEC unit).

[jeffp]

I know full well what the dyno sheet looks like I was there remember. You are correct regarding the cam, it is dropping off at the higher rpm levels. I am well aware of this also. Two things there, the clutch gave a good puff of smoke, and died, see the sharp dropoff on the one sheet, and I have a good reason to believe it was slipping before that also. Second, I am running the cam 4 degrees retarded and that will affect the topend Hp and torque. I am doing another run this thursday with a new clutch, and I am going to do a first run the way it is, and adjust the cam timing and do a few more to see exactly what this grind is doing in the engine. I will be able to make adjustments in the frind from that data, and you are correct James regarding the power band range, that is what I am shooting for.

The turbo, I would be very interested in calling that company that builds the turbo for JWT because I am quite sure they dont do it themselves, no question about that. So you think I should run a standard shaft, sounds reasonable to me. I dont have my data sheets in front of me so I dont know the specs of the stuff you have mentioned.

Yes the goal is to get the engine to produce power and torque, at least for me to about 6800, I am having trouble getting the T5 into second gear @ 7000 rpm, I hate that tranny, and the worldclass is no better.

REGARDING JWT, I did call today and tried to speak to Clark, cant get thetime of day from him. I have been calling for about 2 months regarding the MAF issue, but there has been no new information on the unit, and you know what, I am about to say hell with it and go after market. I really should have been after market from the get go, but I did not decide to get that much Hp until later.

The stock manifold, now there is the question, can it do it, well, I know it will do 500hp, and I dont know of anyone that has tried 600hp in these cars to begin with, and I dont know of anyone who has tried to get it with a stock manifold either.

So you think the HKS waste gate is the best? I was thinking along the lines of the race gate, but I have not been able to put my eyes on the unit. One thing is true tho, to dump that much exhaust to maintain 7psi, andthat is what I want to be able to do with the unit, run it stock if I want to, I will need a good unit with a big hole LOL.

I,m open to different ideas and considerations, needless to say I really like to build overkill to get the long lasting part no question about that.

so anyway how is your system doing in your car James? I am glad to hear from you again, I thought you dropped off the face of the earth or something, you just moved where you hang out. I have to admitt I am liking this forum a little better these days myself.

[Lockjaw]

James who are you getting your turbo's thru that it is that cheap? I need one.

 

I don't want to create to much of a stir here, but it seemed to me like the picture of TimZ's engine had a stock manifold on it, and he is making big power. Granted he had a big external wastegate mounted where the turbo normally goes. I also recall his power seemed to head downhill after about 6k too.

 

I think the thing JeffP and I don't like is the wait until 4500 rpms to make decent power. Jeff has a light flywheel, and a huge turbo is not going to work with the flywheel and launching a heavier car, IMO.

 

Besides you are talking about 2500 rpms worth of powerband, whereas the hybrid would have 3500 rpms or better. I would hate to have a turbo car that I had to drive like I stole it for it to move on the street.

 

If I can get a P trim with a 60-1 or a 62-1 in it that will be fully boosted by 3500 rpms, then I will buy one of those instead of a hybrid, just tell me who to call. I have a manifold set up for a T4 anyway. But waiting until 4500, no thanks. Not with a street car.

 

Besides we have an 11 second hybrid equipped car that managed that feat at 5600 ft above sea level. Seems to me that if he can do it, we can do it too. I would like to see him and one of you guys go at it in the 1/4 mile. Might be interesting.

 

Oh, and the stage V has a heavier shaft than a stage III. At least according to Turbonectics and Jaime at MJM.

[Lockjaw]

JeffP I am not sure if you know this or not, but after lunch, they won't let anyone talk to Clark out there. I always try to call him about 10am.

 

If he keeps dodging you, let me know and I will call him and ask him about flowing the MAF. I have talked with him about it before, he knows I need a new turbo, and he would not expect me to be asking about stuff like that.

 

Not saying I have pull or anything, just that I seem to always be able to get thru to him. besides, I want to ask him about going a little larger on injectors or bumping the fuel pressure anyway.

 

Let me know about the dyno results too.

 

James, I am serious about the P trim. If it will be boosted by 3500 and not be restricted to boost that early, tell me who to call.

 

LJ

[jeffp]

It's not a matter of calling at the wrong time, he just wont talk to me about it. I have called at 8:30 9:00 10:55 and I have tried getting him on the phone just before closing. I really think it boils down to the fact that he has not done anything to get the data on the part, there are newer projects to do to keep up with the newer products. I could be wrong, because I do know Clark works his hinny off there.

I agree, I dont want to try to drive a car on the street that has relatively low power until mid point ofthe rpm range. 4500 rpm is a bit much for me just forthe sake of that kind of power. I do like to drive the car to, and boy just with the clutch I have had to get for the thing, that even makes it less fun to drive. Yea I would be interested in a cheap turbo also, and hey if I can get a build for halfthe cost of what this one cost, then I would be willing to try different combinations to get the best one, what the heck it's only money right LOL

Realistically I am needing about 30psi and I want a little head room in there so I can keep the efficency up regarding air temp. i want the air as cool as possible and get what I need. Either way I need about a 3.3 PR with this thing, and I think to get that and the air flow with a 60-1 is pushing it a little, but I could be wrong. i would like to takk to more builders then just turbonetics. They dont come across as being the most knowledgable on the different builds.

[RB26powered74zcar]

This is only a T-61 but combined with stand alone, proper fuel flow, air flow, and LOTS of proper tuning, I hope to be in the same league with TimZ and James soon.

James, you ready for me to come back out there for another tuning session? hehe

 

I hope I did this pic stuff right...

Joel

[RB26powered74zcar]

Hold Up. There was supose to be this awsome looking picture with the last post.hehaw

Let's try this one more time, if it don't show, you'll have to thrust me...

Joel

[clint78z]

Some good discussion going on here, things have been kept fairly civil.

 

JWT is a fairly good company with some good knowledge and decent business practices. For some ppl it's a good route to go. They do make quite a bit of money on their turbo's, you pay more money for a turbo which is the same as any other garret turbo. The specs are hidden, but they know how to make good street/strip power from a T3/T4 turbo. JWT ecu is plug and play at first, but to really get it good dyno time is needed. As this time adds up, and programmable ECU starts looking like a better option if you know what you are doing. 3bar map sensor no problem, bigger injectors piece of cake.

 

A T76 on a supra with 24v head and tons more combustion effeciency, and higher redline. Yes they can get away with this bad boy. I don't think a L28 can get away with this on the street.

 

Let's put on the thinking cap for a second. If 2 turbo's have same effeciency maps they can have different charachteristics on the car.

 

1) The bigger wheel usually needs more spool up time, radius og gyration thing

2) The one with the bigger a/r won't spool up fast, but may help in top end power if the other a/r was too restrictive.

 

Another word turbo lag or what rpm it spools up at. BE WARY every single time you hear this until you know all the facts behind this.

 

For example a small turbo may acheive it's max boost (17psi) by 2800rpms. A bigger turbo may achieve it's maximum boost (25psi) by 3500rpms HERE'S THE CATCH the bigger turbo may come close to acheiving the same or even more power by 2800rpms.

 

Selecting a turbo to acheive 600hp on the street will probably become a very fine line between too big and too small. It's like goldie lock's and the three bears, finding one that's just right. A T66 is probably ball park.

 

James is rightabout you package right now, it is very impressive but alot of the JWT is about maxxed out. Turbo, injectors, MAF are all on their upper limits.

[Lockjaw]

Clint comparing two different turbos with two different boost levels is not even close to making a valid comparison. Heck I would hope my hybrid would trounce a stock turbo wherever it acheives its max boost.

 

I think both Jeff and I have said we would be ok with 3500 rpms, we don't like the 4500 rpm figure James threw out there.

 

Imagine how much of a pig a 3100 pound car would be if the turbo did not make much boost until 4500 rpms. Yeah it would be fast when you were on it, but part throttle around town would be soggy at best, unless you ran higher compression. It is different when you compare a 240z to a 280zx.

 

I had a pig of a turbo before, and I liked it when it was boosting, but when it wasn't it sucked. With a T5, there was no short shifting on the first to second shift, or it would drop off boost.

 

So you end up with the following on the street. In between first and second, when you would normally shift, you are way away from boost. Suppose someone besides you decides that is a good time to hit it. What are your choices? Shove it up into 1st and spin and hit the rev limiter, or leave it in second and wait and wait and wait for the boost to get there?

 

Both options suck. I usually chose the second one, and when I did catch the person, I went by them, but you know, by the top of third gear I am going close to a hundred. Yeah I went by them like they were going backwards, but it is kind of a hollow victory. Kind of like the 11 second DSM I raced at Steele a while back. He was on slicks, I was on drag TA's, and I beat him thru the 1/8th. OF course he put it on me in the next 1/8th. One the street where I can run my drag ta's and he can't run his slicks, how long do you think it will take him to catch me? He likely won't.

 

What is ok with one of us, may not be with others. Yeah I think pounding out 600hp on a dyno would be nice to brag about, but if it has a very narrow powerband, it is not a fun street car. I would rather have less HP and a fun car.

 

I have not ridden in either James's or Tim's car, so I don't know what they run like. I might find after a ride on Tim's Z that it is plenty driveable, but he hasn't chimed in and said anything yet. I saw his dyno graph, and it is impressive. I might decide I could deal with the lag to get that kind of HP, but without riding in his car, I can't say I like the idea.

 

I am not taking anything away from them or what they have done. what they can accept I may not be able to. It would be nice to know what these guys run too. I mean big HP numbers are nice, but what do their cars really run. I want to run 11's all day long, and figure I need about 100 more HP to get there.

 

Then I can put all that stuff in my 260, drop about 500 pounds or so of dead weight, and run a little better.

[D83ZXT]

I think James is right on! High hp (and don't forget torque)can be made but it requires a system that is matched in all regards, cr, cam, valve size, cubic inches, rod length, intercooller, backpressure, tuning, etc. but most of all... cfm and compressor efficiency. All things being equal 1.6 cfm equall 1 hp. But only up to a point. Non-cross flow two valve heads don't make Supra or Honda hp levels.

 

Think about focusing on your cfm requirement,where on your power band you want it and the limitations of your engines' breathing capability and charastics. High hp comes from the volume and temp of the inlet air, not just psi. In order to make 500+ hp you will probably have to give up some spoolup response under 4000 rpm. Talk to a pro, someone like Reed at Turbo Specialties, or the turbonetics guys. Tell them your goal and let them do their thing.

 

James mentioned the euro spec t3. A friend of mine TimO is running a euro spec tangential t3 on a fully built 2.8 in a 240z with twm induction and a well tuned Tec II. His turbo puts out about 860 cfm at 18 psi with over 80% efficiency, spools to 18 psi by 3800 and pulls to 7,500 without any fall off. He hasn't put it on the dyno but this euro spec t3 hybrid spins the tires all the way through second gear and half way through third. My point being he had a pro size the turbo for his goal.

 

Do it your way, make it unique, but consider talking to a pro about sizing your turbo. If the person doesn't ask about your cam, induction, cr, etc blow him off and talk with someone who asks the right questions and will custom design a turbo exactly for you.

 

Good Luck

Donna

[D83ZXT]

Opps...

Hi Joel! LOL I recognized that motor of yours, but I didn't connect your handle. Sorry

 

PS....

New update not using the StageV, but the R-StageVI. The rest is shhhhh.....

 

Donna

[jeffp]

Clint is correct about the fact that this system is maxed out right now. The injectors are running 100% duty cycle at WOT under load. I am with James regarding the injectors, I never thought they should have been used, but when you stop to consider the thinking behind them it makes total since. The system was designed as a 450Hp system and that is exactly what it does. The system can be upgraded slightly to 500 Hp with the ford exhaust turbine housing. The parts are cost effective for them and they can make a profit on them. They also fit the fuel map electrically regarding max flow rate at the 4 bar fuel pressure to wirk excellent with the configuration of the Nissan ECU. The Ford Maf was an add on later to offset the cost of a defective Nissan part that costs 500.00 or so. Also the Ford MAF set the scaling voltage to .7 VDC as compaired to the 2.2 VDC the Nissan part requires to meter the air correctly. So I understand the reasoning and the design totally.

I am really waiting on Clark to see if he can turn it up to a 600Hp system and still maintain the reliability that the Nissan ECU offers. the injectors will change to 72Lb parts and the fuel pressure will return to stock pressures.

The one thing that I have NEVER liked about the system is te fact that I cant tune it, only Clark can, and from a business stand point that makes total since to me that they keep their product under control and maintain a source of income from it after sales money, very savy.

What I really need is some good data regarding the exhaust at it's current level to be able to effectivly make a determination as to where the next step will be. I need to check the back pressure of the system to get a better idea of what is needed and take a good deal of the guess work out of the equation.

I do have a number of things going here at once so I really need to attack one issue at a time. The Cam is a concern for me at this point, but I am not sure the system will be able to support a cam up to 6800-7000 rpm.

Flow, now there is one topic that almost always get left out like Clint said I think it was and pressure is always the topic. You need the flow as well as the pressure to push the fuel/air into the cylinder. pressure does you no good if you cant get the required volume of air. Think if it as a 1/2" hose running water at 10psi and compairing that to a 3/4" hose running water at 10psi, now which one will fill the bucket first, right, the 3/4" hose because more water can run through the bigger hose.

here is another good one, Compression, what the heck does compression have to do with all this, and combustion chamber size. I did a little off the norm for these engines. I upped the static compression on my engine, and you know it worked out very well for me. A similar setup to what I have takes 6 more psi to develop the same power. Combustion chamber, there again, you will be able to fill more air and fuel if it is bigger. What does that translate to? Well for one you get more combustible fuel and air into the chamber, so we are back to the hose example more, is better, and it takes less effort to get it. You can run a 2" piston engine up to 400psi and you will get gains, but you take a 4"piston engine and push up the compression to 400psi and you have a wild cat on your hands, more is better, we are talkin swept volume here guys, bigger is better.

 

I am running about 48 Lbs an minute with my setup @ 450Hp, and it is running off at the top end. Now is that the cam and it's inability to let the engine breath, or is it the volume of air and fuel available for combustion, good question. For now I think it is the cam, and later I think the turbo will be blowing all it has at the topend but cant get the pressure ratio required to fill the cylinder to the desired 3.3 PR that is needed for that piston/cylinder/combustion chamber to have enough explosive power to create 100Hp pushing down on the rod to turn the crank.

I agree with Clint, the T66 looks like the best choice.

I dont know about all of the new turbine wheels out there so I am going to have to get some sort of data sheet on them. I would very much apperciate any input from all of you as to who I can call that knows their stuff to discuss this issue with. I am thinking I am going to have to relieve some of the back pressure in the exhaust manifold, so that was the reason for the stage 5 wheel, it is bigger and will flow more air. Like James said, if the engine can take in 850 CFM, it needs to be able to exhaust 850 CFM as well, my terms, the huffs have to be close to the puffs or the engine gets constipation and will not run to it's capacity, like sticking a bananna up the tail pipe and expecting the engine to run like a race horse, not going to happen.

One thing that this has done for me tho, I am getting very near to getting a new system. I have all the funds I need to do it and if I cant get Clark to help me out here without waiting till I die then thatis just going to have the way it will be, and in that case I have a whole new set of upgrades to do for the car and they aint going to be cheap. Anyway, thanks guys this has been really cool, I really dont get much of a chance to really talk engine building fundimentials in detail to much with people who know what the heck they are talking about. I really appreciate it and please keep the ideas coming, I love this stuff.

[TimZ]

Originally posted by Lockjaw:

I don't want to create to much of a stir here, but it seemed to me like the picture of TimZ's engine had a stock manifold on it, and he is making big power. Granted he had a big external wastegate mounted where the turbo normally goes. I also recall his power seemed to head downhill after about 6k too.

 

I think the thing JeffP and I don't like is the wait until 4500 rpms to make decent power. Jeff has a light flywheel, and a huge turbo is not going to work with the flywheel and launching a heavier car, IMO.

 

Okay - I'll chime in...

 

First off - I understand what you are saying, and I'm not offended in any way by what you said, but I do need to make a couple of comments...

 

Yes, I'm using a modified exhaust manifold, but the turbo is mounted where the stock turbo was, albeit with a T4 flange. The wastegate is underneath. Take a look at Joel's manifold above - it's very similar to mine. The manifold has been ported to allow better flow near the turbine inlet, and the wastegate is positioned to give the least disruption of flow. I simply like the robustness of the cast manifold, and haven't been terribly interested in changing to a header (James gives me sh!t about this about every other time I talk to him ).

 

As far as the power heading downhill after 6000, yes, it's all the way down to ~380rwhp by ~6200 - (pretty doggy, I know ). Please bear in mind that I am not using anything particularly special for a cam - it's just an Isky L475 grind - their mildest turbo cam, retarded 3 degrees. I use it because I like it's driveability - it gives good part throttle respose, pulls good vacuum, and still has decent (but not spectacular) top-end.

 

Also, you keep talking about not making decent power until 4500. While my curve doesn't start to flatten out until around 4200rpm, I'm making over 300rwhp from 3800rpm up. Yes, it's a pretty rapid rate of change there, but the point is that you don't have to wait as long as you might think.

 

Is my car driveable? I guess I don't know what your criteria are. For the most part, the off-boost response is quite good - the low compression doesn't hurt here nearly as much as people seem to think. Also, the car drives pretty much like a stocker when I'm at part throttle - which is exactly how I want it. Will it pull hard from 1000rpm in fifth gear like a Viper? Nope. Will it pull hard if I put it in the right gear? Yep. Is it hard to get the boost to come on? It's never seemed to be much of a problem for me.

 

As far as turbo sizing - I guess I'm not that familiar with the T3 turbine housings that are currently available, but it seems to me that it's unrealistic to expect one of these to be able to get you to full boost at 3500rpm on an L28, and then have low enough restriction to flow 600hp's worth of exhaust gas at a reasonable turbine inlet pressure.

 

A large wastegate will help here - I wouldn't even consider anything smaller than ~45mm. However, that big compressor is going to need alot of power from the turbine in order to make 600hp worth of airflow at a PR of 3.3. The end result will probably be that this will require fairly high turbine inlet pressure.

 

The problem here is that high turbine inlet pressures (more specifically, a high exhaust/intake pressure ratio) are what makes turbo cams sensitive to valve overlap, which is what makes it hard to get a turbo cam to make power on the top end.

 

The bottom line is that we don't have the luxury of variable valve timing or even switchable intake runners, and they don't make a variable A/R turbine that will support that kind of power (I keep hearing that they are really unreliable, anyway). So, if you really want to get to 600hp on your L28, you are going to have to make some compromises.

 

Here's something that I've wanted to try for a while - it should be possible to take a split tangential turine housing and modify it so that one of the halves has a flapper door in it. You might be able to modify a T3 internal wasteate assembly to do this. Anyway, you could then control the exhaust flow through half of the turbine, and effectively alter the A/R. It would probably be a pretty much on/off kind of thing, but you could get your A/R to go from, say, 0.5 with the door closed, to 1.0 with the valve open. This should go a long way towards giving good low en response, while preserving top end power.

[TimZ]

Originally posted by jeffp:

Flow, now there is one topic that almost always get left out like Clint said I think it was and pressure is always the topic. You need the flow as well as the pressure to push the fuel/air into the cylinder. pressure does you no good if you cant get the required volume of air. Think if it as a 1/2" hose running water at 10psi and compairing that to a 3/4" hose running water at 10psi, now which one will fill the bucket first, right, the 3/4" hose because more water can run through the bigger hose.

Along these lines, I prefer to think of pressure as simply the byproduct of trying to flow a given amount of air through the restriction of your motor. The less restriction, the less pressure is needed. If you think about it, 600cfm through a 2.8 litre motor and 600cfm through a 5 litre motor will both result in pretty much the same output power from both - the manifold pressures required to get there will be quite different, however. If you try to run the same manifold pressures in these two motors, the output will be vastly different. I think people get hung up on the pressure thing, simply because pressure is what gets regulated in order to keep a turbo from running away.

 

This point is more obvious on supercharged cars - generally, for a given supercharger, the boost pressure comes out to whatever is required to get the supercharger's output through the engine. As a result, less restrictive engine setups usually result in lower boost pressures, but they also usually yield more power.

here is another good one, Compression, what the heck does compression have to do with all this, and combustion chamber size. I did a little off the norm for these engines. I upped the static compression on my engine, and you know it worked out very well for me. A similar setup to what I have takes 6 more psi to develop the same power. Combustion chamber, there again, you will be able to fill more air and fuel if it is bigger.

Okay - the compression ratio is what determines the combustion efficiency of your engine (i.e., how much power you get by burning a given amount of fuel). Higher compression ratios are more efficient. The problem is that higher compression ratios also result in a higher temperature rise as the fuel/air mix is compressed. If you go too high with the CR, the temperature of the fuel/air mix will get high enough for it to ignite, causing detonation.

 

Interestingly, if you look into the thermodynamic equations for the Otto cycle, you'll find that the amount of temperature rise is dependant ONLY on the Compression Ratio, hence the final temperature at TDC is determined by the temperature of the air at the beginning of the cycle, and the CR of the engine. Contrary to popular belief, it is not dependant on the pressure that you start at. Read that a couple of times before shouting that I'm full of sh!t . The problem that turbocharging adds is not the pressure, but the fact that it tends to increase the starting temperature of the combustion cycle.

 

Okay - well I thought it was interesting, anyway.

 

As far as the combustion chamber size thing - do you mean displacement, rather than combustion chamber size? They are two different things. Larger displacement will do the stuff you mentioned re: getting more air/fuel in. However, a larger combustion chamber by itself will only result in a lower compression ratio. While this will give you more resistance to detonation for the reasons stated above, it does not cause more air/fuel to get pulled in.

[240Z Turbo]

Come on guys, let us not beat around the bush! BTW, my cost on that turbo is $475 with all new Garrett stuff. Anyway, let us look at your dyno graph.

You may have made 380hp, but for 1/10 of a second before it disappeared to 280hp@6500rpm. I am not knocking your setup and I am not mad, but I want you to reach your goal of 600hp. Also, the stage V wheel was around 5 years ago when I ran a hybrid turbo. What good is a turbo that spools at 3K makes peak power at 4K and is down at 5K. Although that seems to be more of a cam issue. Peak power from 4500-7000 is where it is at. Pull the car to 7K, shift and the next gear is still above 4500 and you are still in your power band. The only way to properly run that hybrid would be to run the monster HKS 60mm GT wastegate so that you do not have unwanted backpressure in the system. Also, will the shaft on a stage V wheel hold up spinning a T66 compressor at 30psi?? Probably not for long! Folks, I am not mad but why not skip the BS and go straight for a 600hp winner. Here is an option. run a big shaft P-trim in a european t3 turbine housing and run a GT 60mm wastegate. Also, what is the feasibility of flowing 600hp through the stock exhaust manifold. Remember, 600hp worth of air going into the motor has to be able to get out of the motor. JeffP, take it from me and others like TimZ about making alot of power. It is not impossible, but it takes some experience. TimZ please chime in on this one...I know you want to!

[Lockjaw]

I appreciate your input Tim, and everyone else's as well.

 

As I said, I have a T4 manifold, so I can go either way on a turbo.

 

As for Reed, I have nothing but respect for him. He is a nice guy.

 

That said, my current turbo has lasted over 4 years with nothing but abuse. It has never been under 15 psi, except when I drove it home from the muffler shop. Right now a simple rebuild would fix what ails it.

 

I kind of like it has lasted that long. I expect my next turbo to last that long as well. I don't care if someone warranties their turbo's and has good customer service if their turbo's break. Taking my turbo off is a pain in the neck.

 

If the person who built my turbo was still with us, I would have no problem having him build me another one. Since he is not, I have to find someone else.

[jeffp]

As far as the combustion chamber size thing - do you mean displacement, rather than combustion chamber size? They are two different things. Larger displacement will do the stuff you mentioned re: getting more air/fuel in. However, a larger combustion chamber by itself will only result in a lower compression ratio. While this will give you more resistance to detonation for the reasons stated above, it does not cause more air/fuel to get pulled in.

 

You are correct in your reply, what I failed to mention, my brain was getting ahead of my hands, is that generally speaking larger combustion chambers imply larger valves, sorry for the lack of information on that one.

You know the flapper idea is an interesting idea. I dont know if it has been tried, but what if you setup a flapper type configuration like you mentioned and utilized a second waste gate actuator that was programmable with a boost controller similar to the electronic units that are used for the waste gate. You would be able to for instance in my case with the Blitz unit be able to set the gain of the unit that would control how fast the flapper opened at a set output pressure from the compressor. That would be fun to play around with in our spare time LOL Really that would in effect make this variable A/R turbine housing that everyone has tried to perfect, but have had nominal success with, at least in my opinion. There could be units out there that work just fine, but I know of only aircraft units that can do that.

[Lockjaw]

Now you are getting WAY too advanced for me.

 

I just want to go fast, and I need a turbo.

 

I guess since I don't want 600 Hp I can go with a stage V.

 

I also think the Nissan European housing is a .82 AR. I am not sure there is that much difference in the different nissan housing's beyond that. At least that was my understanding from talking with Clark at JWT. He suggested I try and locate one of those, except it won't work with my downpipe since I have a turbonetics style swing valve assembly.

 

I also have the block off plate to run an external wastegate, and will likely do that soon too.

[240Z Turbo]

LockJaw, are you speaking of Walker building your turbo? Now the $475 I mentioned is from a different supplier. My buddies shop has swapped to a Garrett distributer and I can get anyone a brand new Garrett T3/TO4E(stage3), .63 a/r, and 50/54/57 trim for $600 with a 1 year. warranty. These turbos are all NEW, not used crap and are delivered w/in a few days to you. If you are interested send me an e-mail to my yahoo account.

turbo240Z@yahoo.com

I can also get full T4 turbos to your spec. BTW, these turbos do not include internal wastegates, but they can be added for an additional cost. BTW, I will dyno my car within 2 weeks and show the power curve. I just recently had my converter tightened up so it should make a big difference in the power output to the wheels. I dynoed the car about 2 months ago with the 5800stall converter @10psi. On the dyno sheet from 40mph to 84mph the curve was completely flat at 267hp@wheels. BTW, 84mph was about 6700rpm. The flat curve indicates that I was blowing through the converter as it was way too loose and inefficient. I suspect the new converter will put about 315@wheels at the same 10psi. Although I have not played with cam timing, the car seems to pull very strong to 7K at the current 15psi of boost.

Some good news today, my Nitto Drag radials just arrived(275-50/15)