jeffp Posted December 18, 2005 Share Posted December 18, 2005 I have never reved past 5K now that is funny. I did the ONLY testing that I know of on the turbo and the .63 A/R housing. my test consisted of 7000 rpm's @ 23-25 psi of boost good enough for you? I never reached the crossover point. oh and BYW the engine was producing 498 hp give or take a few hp at the crank at that time. Total pain in the *** to test, but I did it before I got my third turbo for the car because I was deciding on the turbine housing A/R because I was afraid I was going to crossover with an additional 100hp. The third turbo housing was a .70 A/R part and it killed my spool, then I tried the stock .82 A/R for the gt35r turbo, same results, killed my spool. My cam came from Isky, a grind that Ron thought would work well, .585 lift intake, .540 lift exhaust 290 duration. I wont recommend a grind because there are just to many variables to get a cam in your application and have it work well. But a general recommendation is to go high lift, relatively short duration, and overlap if it is a turbo application. Quote Link to comment Share on other sites More sharing options...
thehelix112 Posted December 18, 2005 Author Share Posted December 18, 2005 Jeff, I'm still not sure what you're talking about. Have you revved your car past 5000 with the GT35R 0.63 configuration? If so, is this http://www.angelfire.com/extreme/280zxt/images5/Graph1.jpg the dyno graph for it? Dave Quote Link to comment Share on other sites More sharing options...
jeffp Posted December 19, 2005 Share Posted December 19, 2005 I haven't gotten the dyno results from my new setup yet. The car was misfiring due to a defective MSD HVC coil. I will get the rreults here in a few weeks. data is data, I have gotten it and I know what this turbo will do. anyway, it's just a suggestion take it for what it is. Quote Link to comment Share on other sites More sharing options...
thehelix112 Posted December 19, 2005 Author Share Posted December 19, 2005 I'm struggling to see how the data from an old turbo (assuming its not a 0.63 GT35R) has any influence on the effect a GT35R turbo with that small a turbine housing will have. I'm not trying to have a go, I'm just curious. I'm also curious as to the 0.05" dur of your camshaft. Mine is just over stock at around 220 deg and I make max power around 6000 (I think). Advertised duration means jack ****. Can't wait to see your dyno graph of 0.63 GT35R @ 7000. Dave Quote Link to comment Share on other sites More sharing options...
S15 200sx owner Posted December 20, 2005 Share Posted December 20, 2005 587hp' date=' 26psi, 6000rpm. Dave[/quote'] Thats on a SOHC RB30 right? Quote Link to comment Share on other sites More sharing options...
thehelix112 Posted December 20, 2005 Author Share Posted December 20, 2005 Ya. Small cam too. Makes max torque 4500 or so. Dave Quote Link to comment Share on other sites More sharing options...
drunkenmaster Posted December 20, 2005 Share Posted December 20, 2005 I am wavering on my purchase of the Ford XR6T GT3540 for my 3.0, as you may know it has the 1.06 rear and 0.5 front. 1.06 is a little big but I hope the smaller front will help. I have read a lot of arguments both ways on the 0.82 vs. 1.06 on the 3.0 using a GT30, 0.64 seems out of the question for even the 2.5. Quote Link to comment Share on other sites More sharing options...
thehelix112 Posted December 20, 2005 Author Share Posted December 20, 2005 To be fair, the GT30 0.63 is going to be smaller than the GT35 0.63. And also the internally gated XR6T 1.06 housing isn't going to flow as well as the GT35R 1.06 housing. The 0.5 front won't make any difference to how the turbo spools, its only the wheels' inertia and turbine housing that do it. Dave Quote Link to comment Share on other sites More sharing options...
jeffp Posted December 20, 2005 Share Posted December 20, 2005 I'm not trying to have a go, I'm just curious. I'm also curious as to the 0.05" dur of your camshaft. Mine is just over stock at around 220 deg and I make max power around 6000 (I think). Advertised duration means jack ****.> That is simple, the A/R has not changed between the turbo's. My data told me that I was not making excessive back pressure @ 500hp @ 7K rpm's in fact the back pressure on the turbine was very good, some commented exceptional. What I had a paroblem with was the compressor and its ability to produce boost. I simply ran out of boost @ 23 psi and the compressor went into surge at that point, and I could see this by the pressure going from 23psi to 25psi but not able to maintain the 25psi. So the compressor was out of steam. The exhaust side was working very well at 7K rpms, back pressure was very good, it was the compressor that needed improving. I was running the stage 5 exhaust turbine. Now the exducer of the turbine was 2.448 diameter and that is the bottleneck of the exiting exhaust gases. So the gt35R turbo has the sams A/R but the compressor is bigger, able to produce in the range of 30-35psi of boost. The turbine og the turbo exducer is 68mm so the compressor is bigger, and the exhaust turbine is bigger for an overall higher flow rate then the smaller turbo. The A/R is still compressing the exhaust gases the same as before, but in effect the turbo overall is able to move more air because it is simply bigger, more air flow on both sides of the turbo. The A/R controls the speed at which the turbo will spin. A turbo with an A/R that is to large will not be able to spin the comprerssor effectively until the engine is pumping more air. The A/R that is to small will spin the turbo more effectively and sooner, but you will choke out the breathing of the engine before it reaches maximum RPM. A small A/R will be very effective and get to about 2/3rds of the rpm range, and no matter how hard or fast you stab the throttle, the engine is not going to move enough air to make the turbo boost effective, and what you begin to get is reversion back into the cylinderhead because the pressure on the exhaust is greater then the pressure of the intake. Air pressure will try to even itself out and follow the path of least resistance. so in reality, this GT35R turbo is essentially the same as the TO4E turbo, but on a larger scale. Quote Link to comment Share on other sites More sharing options...
thehelix112 Posted December 20, 2005 Author Share Posted December 20, 2005 Except of course, that a GT35R does not run a stage V exhaust turbine I don't think. Thus the wheel itself, while you are correct in saying it is the same exducer diameter, makes better use of whatever air it is being fed, and will increase exhaust backpressure over the stage V turbine wheel for a given A/R. I think. Unsure of the `stage' spec of a GT35R wheel. Dave Quote Link to comment Share on other sites More sharing options...
thehelix112 Posted December 20, 2005 Author Share Posted December 20, 2005 Just worked it out. GT35R turbine wheel trim: 84 (2.68^2/2.45^2)*100 T3 Stage V turbine wheel trim: 76 (2.798^2/2.439^2)*100 Was it a T3 turbine wheel you were testing? I assume so because the T4 turbine wheels are measured in letter trims? N...Q I think? I'll be surprised if they behave the same. Dave Quote Link to comment Share on other sites More sharing options...
jeffp Posted December 21, 2005 Share Posted December 21, 2005 The turbo I was running with the stage 5 exhaust turbine wheel was the T3 size. The T3 wheel : Major= 2.795" Exducer= 2.437" The Gt35R turbo Major= 3.307" (according to the previous post, I dont recall what I measured) Exducer= 2.677" That I am sure of So it is easy to reconize the turbo is essentially the same, but with a bigger compressor, and turbine wheel. You will notice, the slip ration has changed little between the two. The GT35R turbo is able to flow more air, both on the compressor side and the exhaust side of the house. Now I did my testing with the TO4E turbo I ran with Very good results in back pressure. Keep in mind the exhaust turbine housing was machined to fit the bigger exhaust turbine wheel. Also unlike the exhaust turbine housing of the GT35R turbo, the exit of the TO4E turbo dumped directly out of the back of the turbo, similar to air through a strait pipe. I don’t know how well versed you are with flow through a pipe, but a strait pipe actually creates turbulence at the exit point that has to be dealt with. The turbulence will hinder a smooth flow out of the turbo, so some flow is lost with that configuration. The GT35R turbo, if you take a look at the exit of the flow starts at the exducer size, and then opens up at a nice 7 degree angle to promote flow, to feed into a 3" pipe. Thus the GT35R turbo promotes flow out of the turbo and into the exhaust system, provided you don't neck down the exhaust pipe and downpipe. So in conclusion, the GT turbo is very similar to the TO4E turbo I was running, but more efficient regarding exhaust flow, and the ability of the compressor to flow a larger amount of air on the intake side of the house. The difference between a .63 and .82 A/R housing for spool is about 600-800 rpm's best case situation. The .63 A/R housing is much more efficient at spooling the turbo at lower rpm levels then the .82 housing, but with a properly sized exhaust system you will have no problems with excessive back pressure. My engine application, well there have been some significant improvements in the exhaust flow numbers through the cylinder head. The intake numbers were unchanged for the most part, so I am able to flow much better on the exhaust, and have gotten to that mysterious 70% flow of the intake that appears to be the constant for a well breathing engine. There is no doubt in my mind this turbo will do eaxctly what I wanted it to. It was unfortunate the MSD coil went out to lunch and screwed my first dyno test and tune. However, I know of one other car that is built similar to my engine, just not as efficient, and the bottom end not as agressive in compression, and the cam not quite as agressive also, that last dyno yielded him 700 foot pounds of torque at the rear wheel. The dyno chart you posted was in fact the chart of the TO4E setup, and yes I was not very happy with the results at the higher rpm levels, in fact it appeared very similar to a stock engine. I was not to impressed with that seeing I had an after market cam I designed the grind for that should have increased the peek power rpm and topend of the engine. Only after I pulled the engine down did I begin to find out why. Seems I had a head gasket leak in between 2 and 3 cylinders, that at the time I thought was unseated rings because it was a new build. That leakage explained why the engine, although was making twice the power appeared to be down in power. The second thing I have come to realize was the cam and the way I was running it. The cam timing was retarded to get some lowend power, and in addition to that the valve lash at the time was incorrect causing the cam profile to change significantly to the point that it made essentially the same power curve as a stock cam would. I realized this when I decided to degree the cam, in stead of using the stock timing marks that most builders use to set up their L series cam. The stock Nissan marks on the cam sprocket and the can back plate. When I degreed the cam, the lobe centers wer no where near what I specified, the opening and closing points of the cam wer way off as well. So no wonder the engine had a short peeky power band. This new build is excellent, the off boost response is excellent, and the car begins making boost at 2500 rpm's and spools very nearly as it did before, if anything a 100-200 rpm loss in spool, well within tolerances of a very well rounded street and strip car. the car picks ou the gears almost transparently to me as I shift. The transistion from no boost to full boost is excellent. I am happy with the build. Now all I have to do is to get some equipment from vendors that will do what they advertise and not go out to lunch in a short amount of time. I guess it's back to old school ignition components, the Mallory Voltmaster is definetly in order for a coil. Quote Link to comment Share on other sites More sharing options...
thehelix112 Posted December 21, 2005 Author Share Posted December 21, 2005 The Gt35R turbo Major= 3.307" (according to the previous post' date=' I dont recall what I measured) Exducer= 2.677" That I am sure of[/quote'] Thats not correct I'm sorry. The GT35R turbine wheel diameter(exducer) is 64mm (2.677") and the trim is 84 (not 84mm exducer to get your 3.307"). The inducer is 2.45". Look forward to seeing dyno graph. I predict a fall off in torque around 5500. Dave Quote Link to comment Share on other sites More sharing options...
260DET Posted December 21, 2005 Share Posted December 21, 2005 Does this GT35R -v- TO4E comparison take into account the improved aerodynamics of the GT? jeffp did mention the exhaust flow out of the GT35R, what about the internals? Anyway, jeffp's dyno sheet will be interesting. Quote Link to comment Share on other sites More sharing options...
S15 200sx owner Posted December 21, 2005 Share Posted December 21, 2005 Does this GT35R -v- TO4E comparison take into account the improved aerodynamics of the GT? jeffp did mention the exhaust flow out of the GT35R' date=' what about the internals? Anyway, jeffp's dyno sheet will be interesting.[/quote'] Yes, also waiting with baited breath..... Quote Link to comment Share on other sites More sharing options...
thehelix112 Posted December 22, 2005 Author Share Posted December 22, 2005 Richard, My only point is that a TO4E/T3 hybrid with a stage V trim turbine wheel is not equivalent to a GT35R. A GT35R wheel is less agressive trim. The improved flow from the turbine housing design might not be enough to overcome this. We'll see. 0.63... I can't imagine needing more response than I have now.. but to each his own. Dave Quote Link to comment Share on other sites More sharing options...
260DET Posted December 22, 2005 Share Posted December 22, 2005 Yes, there is no comparison between the old hi flowed TO3 on my two liter and the present GT28RS. The RS gives 60-80 more hp* at the wheels, spools up a lot more quickly and carries boost while driving around town at a level the TO3 never came close to. Can't understand why people still mess around with the old technology *at a higher boost level than the TO3 could reliably be run. Quote Link to comment Share on other sites More sharing options...
jgkurz Posted September 1, 2006 Share Posted September 1, 2006 Hi JeffP, Were you able to dyno your car with the GT35R and .63 turbine housing? I am looking at doing a similar setup and was curious about your results. Thanks for any information or experience you can offer. Quote Link to comment Share on other sites More sharing options...
Guest 81zman Posted September 2, 2006 Share Posted September 2, 2006 portland oregon, I am in saint helens. we need to get together. Quote Link to comment Share on other sites More sharing options...
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