jeffp Posted August 2, 2002 Share Posted August 2, 2002 That is not a bad cam grind, the thing with it is that you will be limited on the Hp and torque to the lower rpm ranges, somewhere in the 4500-5500 range. Generally, the longer the duration of a cam the higher your hp band will be, to a point, and depending on your setup. A very good street cam is to go with the higher lift and that will give you the rappy engine for the street. The turbo grind, now here is a different animal. The trick is to get the lobe centers advanced enough to get the Torque and Hp into the 6500 range, but still have a smooth running engine. You really want to watch the overlap as this tends to screw up a turbo engine in the way of power developed by the turbo. To much and the turbo fills the cylinder in the intake side and it dumps right out the exhaust side, not good for performance. Ultimately I think this cam is going to run the best split, but I need to get some grinds designed and dyno them to get a better idea of where I am at. The first change is going to be to set the cam I have now back to 0 degrees. I am running 4 degrees retarded right now, and I did that without doing any dyno runs, but just the seat of the pants runs. So to make a deterimination based on what I have done is not the way to approach the matter. I am planning a run here next week with the cam set to 0 now that I have a clutch that wont die in the middle of the run. I am fairly certin the power band will be higher in the rpm ranges, I am guessing about 500rpm, but the dyno will tell all. My goal is to get a broad power band with the aid of the turbo from ranges of 3000-6500/6800 and call it even. With that cam I am quite sure getting 600hp will be very attainable and that will be where I will stop designing power for the car. Whether I can get the JWT fuel management to handle that power rating is the big question. I have been trying to get info from Clark for about two months on the status of the MAF that is the limiting factor for this setup. The last challenge is that I will have to tune for every change I do to the cam timing and grind, so if I cant get any more out of the system it's time to go and I will get an SDS system or halltek system. I really do need the ability to change fuel parameters when I need them and not when I can get them, But if Clark can get the system to run 600Hp then I will do all of me cam stuff and have the system tuned one last time and that will be the end of it. Oh where are carbs when you need them LOL. One of you mentioned I should start selling cams, well that is very possible at this point. I have a grinder, and I can get the billets easily, so the rest is just R&D time for me, and I just may have a way to market them and make a little bit of money in the process. I do know one thing, they sure wont cost 600.00 a billet. Quote Link to comment Share on other sites More sharing options...
TimZ Posted August 2, 2002 Share Posted August 2, 2002 Originally posted by jeffp:You really want to watch the overlap as this tends to screw up a turbo engine in the way of power developed by the turbo. To much and the turbo fills the cylinder in the intake side and it dumps right out the exhaust side, not good for performance. Just a minor point here - unless you are running a really large turbine and A/R, the pressure in the exhaust manifold will be higher than that in the intake manifold. Because of this, the intake charge will not blow out the other side. Instead, the exhaust will back up into the cylinder during the overlap (reversion). The end result is pretty much the same (long overlap = bad), but the cause, and therefore the available solutions, is different. This is a common misconception - probably mostly because this is what happens with a supercharger, since it does not have the high exhaust manifold pressures to deal with. Quote Link to comment Share on other sites More sharing options...
Lockjaw Posted August 2, 2002 Author Share Posted August 2, 2002 I have talked with Clark at length about the limitations of the system. I am assuming you are running the Mustang Cobra MAF like I am. I am pretty certain that the MAF will continue to accept votage beyond 5.15 volts, or whatever the limit is of the ecu. Clark said they could program a step in there, whatever that means. Another option he talked about was rasing the fuel pressure to 4 bar. I have a fuel pump that can handle that sort of pressure. I would rather just bump up the injector size, to 550's, which I think they can accomodate as well. There is another ecu option too. In Sports Compact Car, they had a 300zx turbo that used an infinity ecu that has 2 timers, which allows quasi sequential fuel injection on 3 cylinders at a time. In other words, batch firing 3 cyclinders all the way thru the rpm band versus mine switching over to 6 injector batch firing at 49% capicity since I have one timer. I am going to try this cam I found and see what it does. It has to be better than stock since it is a little larger. I really need something that goes out to about 6500rpms without falling over flat, and you can feel the stock one in my car just doesn't have it. Since I put 3.90's in the back, the thing stays on my rev limiter at 7k, and it is rough trying to shift it fast and keep it off the limiter. T5 and 3.90's means shifting a lot. I need to go to the auto deal and see what that does for me. If you grind some cams, I would be interested. Quote Link to comment Share on other sites More sharing options...
jeffp Posted August 2, 2002 Share Posted August 2, 2002 You are correct regarding the back pressure and the reversion. Thank you for the observation in my terminolegy, that is important. You are right on regarding the A/R of the exhaust turbine housing also, and you are right on with the explination of why a larger A/R housing is utilized in a high horse power application. The trick here is to go high enough with the A/R to still be able to spool the turbo effectively enough so that it doesn't take 5000 rpm's to get a good spool. Here is the plan, and I have been thinking about doing this for some time, but I really dont want to take my turbo apart to install the required fittings, what a pain in the butt that is. I have a 1/2" spacer between the outlet of the exhaust manifold and the turbo inlet. I have enough room to install a 1/8" NPT fitting to hook a pressure gauge to to get a very good idea of the back pressure in the inlet of the turbo. With this data I ccan get a good idea of where I need to stop with the overlap between the intake and exhaust valves opening and closing. VERY important parameter to know whaen it comes to optimizing the cam grind, and NOTE: for this specific application and design, so what I design and grind, will be dependant on how I have my system setup. So with that being noted, here is what I have on the car. I am utilizing a stock Nissan T3 exhaust turbine housing machined out to 2 1/2" to run the T4 turbine. The A/R is .64 so there will be variations of cam grinds depending on the exit size of the housing and the A/R rating of the housing. The last consideration is the outlet of the turbo into the exhaust system, and the is also another point to take back pressure readings as this will determine how well the turbo will spool also. This is why in a turbo application bigger is better, within reason, you want the system back pressure in the inlet of the turbo side, not that that is all that good, again within reason, and free flowing into the rest ofthe system. When you make a exhaust system that will flow everything you can push into it, you have the thing half licked and you can focus on the inletside of the turbo. But that is the plan, man I am getting so tired of getting under this car LOL, but like they always say, if you want to play, you got to pay, and pay, and pay LOL with that being said, I have a call to make to UK regarding a QUAIFE differential. Quote Link to comment Share on other sites More sharing options...
SHANE Posted August 2, 2002 Share Posted August 2, 2002 Just a minor point here - unless you are running a really large turbine and A/R, the pressure in the exhaust manifold will be higher than that in the intake manifold. i was told by the company that does my turbos that the presure should NOT exceed 1:1. if there is 20psi at the intake backpressure should never be more than 20psi and the right turbo will have NO backpressure. when i maxed out my turbo 3 upgrades ago we put a gauge in the exaust manifold. at 15psi at the intake the exhaust had more than 30 psi back pressure. now at 25psi intake, i have 5psi at the exhaust manifold. unless the turbo is not sized right you should not have more pressure in the exhaust manifold. shane Quote Link to comment Share on other sites More sharing options...
jeffp Posted August 2, 2002 Share Posted August 2, 2002 Well they told me to call back Monday, oh well. Regarding the ECU issue. I haven't spoken to Calrk regarding the Infinity ECU and that may be an option. I am running the 300zx ECU now. The offset you mentioned in the ECU for the Ford MAF. What that translates to is this. Normally the ECU is setup with the Ford MAF to meter the air and give the ECU a reading of .6 VDC at idle, about 750rpm. This is the standard configuration for the sport 350-400 package they sell. Now when you start getting into the sport 450-500 package what Clark does is to re scale the ECU to accept a .450 or there about, VDC reading at idle. What this does in effect is enable the ECU to acheive a wider scaling range to meter the air into the engine, and adjust the duty cycle to the injectors accordingly. The second thing they do, and I was never happy with this configuration, but it was done for electronic reasons, is to increase the static fuel pressure to 58.8 psi to increase the fuel flow per injector. This works well, but there are some negative results of the increased pressure, not bad but there all the same. This problem can be easily solved with a larger injector, and they have the 72 Lb injectors. This injector change does require a new fuel map to compensate for the different characteristics of the new injector, but doable. The bottle neck in the system is the FORD MAF, now here is the challenge. Ford specs the part to scale to 5 VDC, but from testing, Clark has learned that it will scale higher then that, so this is a good thing. The maximum reading he has tuned to is 5.59 VDC so any thing after that voltage, there is no metering of the air into the engine. This is the point that I am at with the system. Clark has sent out a MAF to be flow tested to get the maximum voltage out reading of the MAF so that he can continue with the progression of air/fuel metering with the system. The big question is: How high will the MAF scale the air flow and convert that to a VDC reading output for the ECU. This is the information I am waiting on and that will determine if I buy another system for my car or upgrade their system or not. I want to build it to 600Hp and that will be the end of my Hp for my car. I am fairly confident to try to build anything bigger then that will require me to jack up the car and slide another car one in under it. The structure of the car will just not hold that kind of power and torque and not tweek the whole car out of shape in the process. The other major consideration is the tranny, the T5 just will not hold that kind of power and torque and not munch itself. I have been looking into a T56 unit, but have not commited myself to that install yet. The LSD differential will not hold the power and that is why I am trying to go with the QUAIFE unit, but the extent of that install is yet to be determined. I will find out Monday exactly what needs to be done to get that thing up under the car. So thats where I am at with this thing, waiting to see what can be done or not done which ever the case may be. Quote Link to comment Share on other sites More sharing options...
TimZ Posted August 2, 2002 Share Posted August 2, 2002 Originally posted by jeffp: Ford specs the part to scale to 5 VDC, but from testing, Clark has learned that it will scale higher then that, so this is a good thing. The maximum reading he has tuned to is 5.59 VDC so any thing after that voltage, there is no metering of the air into the engine. Do you have the Ford part number for your MAF? I might be able to help... Quote Link to comment Share on other sites More sharing options...
jeffp Posted August 2, 2002 Share Posted August 2, 2002 Hi Tim, no I dont have the part number to the Maf any longer, unless it is on my invoice from JWT, but I cant remember. I do kone it is the Cobra MAF and it is the same MAF that is used in the thunderbird super coupe. I did offer to help Clark out on this thing. I have a realitive that works at Ford passenger cars Engineering Dept in Michigan, and I was going to try to get a schematic of the MAF, because I am fairly sure they are limiting the output with a zener diode to clamp it to it's limit, because there is just no reason to scale it any higher for their applications. I also have a cal lab in my area that does flow testing on Jet engines and I could have flow tested the MAF myself at his place to get the exact DC output ofthe scaling, and the scaling curve of the unit, but did not get to much response from him on the matter. The whole thig is that I want to use the system to get the Hp I am wanting to finish the car off with, and that is why I was willing to go to these lengths to help out. anyway Quote Link to comment Share on other sites More sharing options...
Lockjaw Posted August 2, 2002 Author Share Posted August 2, 2002 Damn I am getting an education. The MAF is from a 93 Mustang cobra if that helps, and it is made by Hitachi. That is what I bought for my car. I might have the box laying around the house somewhere, but I doubt it. Where is the part number on the unit and I can tell you when I get home? Clark told me about raising the fuel pressure, because I had concerns about maxing out their set-up at 450 hp, which I assume is at the flywheel not the wheels. I have got to get a new turbo too, and am not sure which one to go to. I don't want some laggy pig that makes mega power from 4500 to 6500. Mine is at full boil by 2800, and when it hits, it hits hard. I could wait until about 3500 for full boost, but beyond that in my ZX, and I will have to play catch-up, and get my head lights sucked out if I am not careful until the boost comes on. Been there with the rotomaster, not going back. I was thinking about going to a T04E 50 ar with a 60-1 and a 10 blade stage III in a .63 or .82 T3 housing. I figure the 10 blade is worth some flow over my 11 blade unit. Anyway, what about running a dummy MAF like they do on the twin pop charger units for the 300 ZXTT? Seems like it would be simple to fab up. Taht would effectively double your intake flow. Quote Link to comment Share on other sites More sharing options...
240Z Turbo Posted August 2, 2002 Share Posted August 2, 2002 1:1 ratio is very good. FYI, my cam is a Web Cam that has a modified LC. Here are the rough specs: .488" lift 230dur@.050"(intake/exhaust) 110.5deg LC Yeehaw cowboy! Quote Link to comment Share on other sites More sharing options...
TimZ Posted August 3, 2002 Share Posted August 3, 2002 Originally posted by SHANE: quote: Just a minor point here - unless you are running a really large turbine and A/R, the pressure in the exhaust manifold will be higher than that in the intake manifold. i was told by the company that does my turbos that the presure should NOT exceed 1:1. if there is 20psi at the intake backpressure should never be more than 20psi and the right turbo will have NO backpressure. when i maxed out my turbo 3 upgrades ago we put a gauge in the exaust manifold. at 15psi at the intake the exhaust had more than 30 psi back pressure. now at 25psi intake, i have 5psi at the exhaust manifold. unless the turbo is not sized right you should not have more pressure in the exhaust manifold. shane Where were you measuring the backpressure? You're telling me that you had 5psi at the turbine inlet (not at the downpipe) with 25 psi at the intake manifold? Sorry if I sound skeptical, but I'd check those numbers again... Your numbers make sense if you are measuring at the downpipe, but it's pretty difficult to achieve even 1:1 at the turbine inlet and maintain a streetable setup. Quote Link to comment Share on other sites More sharing options...
SHANE Posted August 3, 2002 Share Posted August 3, 2002 measurements were taken at the exhaust manifold, not downpipe. and i missed the "2". it should have read 25psi intake manifold and 25psi exhaust manifold giving 1:1 ratio. now i dont know what you consider "streetable". i dont hit full boost till about 4800rpm. but i dont mind, and turbo lag is very easy to overcome with a 5 speed. since i now have an automatic i will rely on nitrous to get me into boost. my stall will only get me 3500rpm and 5psi. boy do i miss shifting. Quote Link to comment Share on other sites More sharing options...
jeffp Posted August 3, 2002 Share Posted August 3, 2002 Shane, what kind of turbo are you running? The full boost rpm range seems a little high. The engine is running half way to WOT rpm and you are building boost at about the top end of your cam I would guess, I could be wrong on that, but I really haven''t found a setup that will run the Hp and torque into the 6500 rpm ranges. Just out of curiousity, where did they probe the exhaust manifold to get the back pressure readings? Quote Link to comment Share on other sites More sharing options...
jeffp Posted August 3, 2002 Share Posted August 3, 2002 I really dont know what Clark has in mind on the system, except that they need to get arounf the MAF issue some way. The 4 bar is correct, the car will run lean without the higher fuel pressure. You are also correct the 450 Hp rating is at the flywheel, but in my car that translates to 380 Hp at the rear wheel, and since I have stroked the bottom end, the torque is about 428 foot pounds. Now mind you I was still turning up the boost at this point, but the clutch gave out on the car and would not hold anymore power. I am going to dyno the car again next friday now that I have a good clutch to get some data, and I will be able to turn the boost up until it starts running lean, and that will give me the more realistic picture of what the car is doing. Then I start doing various cam work to get the power range to whaer I want it, and then it's off for tuning again, and hope fully the system will be able to give some gains. Quote Link to comment Share on other sites More sharing options...
TimZ Posted August 3, 2002 Share Posted August 3, 2002 Originally posted by jeffp:Shane, what kind of turbo are you running? The full boost rpm range seems a little high. Okay, Shane, now I believe you . What I meant by 'streetable' was exactly what you just described. A turbine and A/R combo large enough to give a 1:1 pressure ratio will generally have a difficult time making boost at low rpm. Basic Physics. Most people seem to like to make their power at lower rpms for the street. Your combo should be able to make exellent power, though. My guess is that you should be much more tolerant to different cam grinds, and be able to tolerate more valve overlap. This should allow you to move your torque peak higher, which would give you even more power. I would guess if you made a sh!tload of power from 4800 to 7500rpm, nobody is going to be too concerned about lag (just pick the right gear, right?). Quote Link to comment Share on other sites More sharing options...
SHANE Posted August 3, 2002 Share Posted August 3, 2002 Jeff, sorry but i honestly do not know what the specs are on the turbo. (other than it is a hybrid) they wont tell me about it because they want it it to be a secret(i guess i have a big mouth). sounds weird i know but they take VERY good care of me service wise and the prices i get are incredible, so i dont mind being in the dark. the exhaust manifold was probed at the number 6 runner. Jeff, i am interested in what you are going do for a cluth. one of the reasons i went to an automatic was i could not find a clutch that would hold. and i promise to start typing slower i reach full boost at about 4500rpm(the eight is too close to the five) not 4800! Tim, as far as the cam goes i am on the stock cam now. i have a schnieder(sp?) sitting in the garage waiting for a home. but with the stocker it pretty much falls on its face after 6000rpm. and yeah your right find the correct gear and the right amount of clutch slippage and lag is all but history and if you dont mind me asking what stall speed are you going to? Quote Link to comment Share on other sites More sharing options...
TimZ Posted August 3, 2002 Share Posted August 3, 2002 Originally posted by SHANE: and if you dont mind me asking what stall speed are you going to? I'm running a manual trans. I'm using a clutch that I got from Clutch Specialties. It's basically ACT's strongest pressure plate with a full face, sprung hub iron disk. So far, I'm very happy with it - engagement is very smooth, pedal pressure is firm but not objectionable, and it gave me no problems on my last dyno runs (or since). It is supposed to be good for 500lb-ft. Quote Link to comment Share on other sites More sharing options...
jeffp Posted August 4, 2002 Share Posted August 4, 2002 I am running a clutch made by superior clutch and it is a killer. The thing holds the power and it is not to hard to push in at all. I will say it is allot more notchier the the centerforce I was running, but it died in 3000 miles and I never ever did a dump it off the line routine at all. This new unit is a four puck type with Kevlar and a semi matallic compound on the pressure plate side. The hub is still sprung as well. I am planning another dyno run this friday, and do a little work on my cam timing and see just what the cam is doing set to 0 degrees. then it's off to the drawing board again for a second grind and I will try that one and I should be just about where I want to be with a final grind. That turb must have a big A/R to make it spool so late, cant say I would like that to much myself. Quote Link to comment Share on other sites More sharing options...
SHANE Posted August 4, 2002 Share Posted August 4, 2002 sorry i thought you had an auto. Quote Link to comment Share on other sites More sharing options...
Lockjaw Posted August 4, 2002 Author Share Posted August 4, 2002 Well if the limit is 450 hp at the flywheel, I have some room left to grow. I bought the bosch adjustable pressure regulator they have so I can raise the fuel pressure. I need a bigger turbo. I run a hybrid with an H3 compressor and a stage III turbine wheel. I was thinking about going to the stage V wheel and a 60-1 or 62-1 in a T04E housing. I don't want to wait until 5k for boost. What about using one of the bigger Mustang MAF's made by the aftermarket? Isn't there a 90 mm one? That would be 10mm larger than what we are running right? I guess he would have to "hack it" to make it work though. I would like to know what you get out of your dyno runs. Gives me an idea of what I can go to. Quote Link to comment Share on other sites More sharing options...
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