Quote from: TookyCatActually I never considered getting a GTP, the only one to suggest that was you when you said if I wanted these types of HP levels, I should look at getting a GTP??   ( http://www.netavalanche.com/tgp/viewtopic.php?p=10882#10882 )

Sorry, I was remembering something about you looking at another car, and when I took a look just now (better than my memory I guess, but you got my point :wink: ) I found you said "I'll have to look into buying a different vehicle and abandoning the Turbo Grand Prix project"  That is what I was refering to!  And as for doing some testing, "I don't have the time or $$$ to do FWD transmission Research & Development" is the other.

Quote from: TookyCatI already addressed fueling in my High Performance post seen here
But nonetheless, I am still wondering if you or anyone else offers such a chip as you're referring to?  Thanks,

So you were still talking back then about addressing the fueling, but not really ready then, or for a turbo upgrade yet :? .  Nothing ready from me fast enough for you back then, or now, but sounds like you are on the track to cover that anyways 8)

Jeff M

Quote from: TookyCatI'd like to offer some clarification between the "Disco Potato" turbo mentioned.  As far as I know (and I'd really like to hear otherwise!), only one person is running a Garrett ball bearing turbo on their TGP and it is not a Disco Potato.  The person in question is "Jud" or "SleeperRed90TGP".  He posted the photos on his website of the install (fantastic stuff Jud!!).  He has a GT28R which is the older style.  According to ATP it's rated at 290HP.  It also has the less desirable bolt-flanged compressor inlet and outlet which is a dead giveaway to the fact that it's a GT28R.  

Here are some references on the web showing the GT28R with its easily identifable flanged inlet/outlet.: http://www.turbobygarrett.com/turbobygarrett/kits/kit_HondaCivic.htm#
http://www.atpturbo.com/root/turbopiping/dimensions/gt28rdim.htm

The Disco Potato is actually the GT28RS which no TGP owner has mentioned actually owning yet.  According to ATP Turbo, "The GT28RS is a new and hot one that would kick butt on this engine.  How would you like it if it spools up faster than the Super60 and make 50 wheel more than it.  It's a much new Garrett turbo than Gt28R so it's quite modern."  Interestingly enough, Garrett itself refers to the turbo as the "Disco Potato".  Take a look at this great high resolution image: http://www.semaphotos.com/photos/C_00375.JPG
Here's another photo from Exile Racing:

So whoever is the first to try the GT28RS will likely have an easier time adapting the intake inlet/outlet than Jud did and may possibly produce more HP as well, seeing how the GT28RS is rated at 350HP by ATP.

Yeah, no one has the disco potato(gt28rs), and the gt28r has a smaller turbine housing(.64 vs .86 of the potato which is smaller than our stock housing .68 IIRC).  That alone is worth the extra money, plus it looks to be an easier install as Josh(tookycat) stated.

A) Taillights for GM vehicles are about to get really expensive!!!!
B) WHAT the hell does that have to do w/ a Disco Potato?????
Answer= Guide Corporation is going on strike as of tonight at midnight if GM/Management has not come to a local/national agreement on wages and benenfits package.  I WORK there, and may not have a job soon we shall see, but I WILL buy a 70's potato IF (and I addressed this on the W board but never got any really good response) everyone agrees that it will (ON PAPER, and theoretically) be a feaseable replacement w/ relatively low fabrication.  Cost is a factor too.  IF this is agreeably a good replacement turbo I don't mind making a turbo/injector/chip/whateverelse combo that can be had by the masses.  I don't mind doing the work or spending the money, I also don't mind having a one off car, but I like other people to be able to benefit from my work if I am to do it.  If no one else gives a shit, I will use a turbo that is more suited for our cars, but this seems to be the only/best turbo suited to our (almost, save the fixing of the DP 5th hole) exact application.  What I'm getting at, is I have no problems buying the turbo and doing the work and making a chip (sorry Josh, only Manual will be coming from my end, those fruity ass auto's can't take the low boost that I like, and after driving an auto TG160 car, and my custom 5 sp.  I'll keep the 5 speed.)  No offense intended Jeff, you gotta keep those trannies alive until your kit is done.   :lol:  My car is just a TON faster, but I hope to see a little more once I get the injectors in there and see what happens.  FWIW, I plan on making an auto chip w/ the same performance attribs that my manual chip has, and using a 4Meg chip to select between the programs (or atleast an adapter)  So you could go faster on the strip where traction isn't as big a problem, and w/ limited use (and a BIG ASS tranny cooler) you can have the performance to make the slips, then go back to keep your tranny from getting the slips.   :shock:  :evil:
This post is getting too long so any questions/comments/want to make fun of me, just lemme know.  :lol:

In an very good but short article by Modified Magazine in their April Issue, turbo size testing was discussed, I suggest it as good reading, though there are many books that say the same, just this one is hot of the press and a hot topic of late here.  Before I quote from them, know these facts first.  This was a small Honda motor (or course) that was turbo?d for this test.  Also the fact this little motor does not have a lot of displacement like a 3.1L motor does, the backpressure resulting tests and hp gains from this 4 cylinder test would be bigger/better when run on a larger displacement 3.1L motor.  In this article the techs were showing the efforts involved and the tests to run when working towards a properly sizing a turbo for an engine, mainly street/strip.

(quoted from Modified Mag 4/2004):
?TESTING THE TURBO?  ?   With the compressor spinning at 120,000 rpms and cramming air down your engine?s throat, how do we know it?s all working well?  There are a few simple tools we can use to gauge its performance.  What comes in much come out!  All of the exhaust gases pass through the turbine side and the easier they do so the more power the engine will make.  The smaller the turbine side, the harder it is for the gases to exit and the lower the effective volumetric efficiency becomes because now he have a restriction in our system (restriction in the exhaust coming out of the engine and before the turbo. JM).  The parameter we want to measure here is the exhaust manifold pressure (back pressure).  The best location for a reading is usually in the collector right before it goes into the turbine housing.  A local hardware store will have the correct drill and tap for a the 1/8? NPT compression fitting that we?ll be using.  Run a length of copper tubing to absorb the heat and keep it away from any materials susceptible to higher temperatures.  A short piece of vacuum line and a 100psi fuel pressure gauge (a 30psi boost gauge is more than sufficient. JM) will work for measurement purposes.  We will do all the testing on the dyno so it?s easy to watch the gauge.  But for any road testing secure the gauge to the windshield (running the vacuum line into the car is fine long as the connections are secure, if one pops off in the car, you get a 1/8 exhaust dump tube. JM).  What we are looking for is the exhaust manifold back pressure verses the intake manifold pressure (boost).  This pressure ratio helps to determine how well the exhaust gases flow past the turbine wheel side of the turbocharger (and get out of the engine. JM).  Most OEM passenger vehicles will have pressure ratios as high as or higher than a 2 to 1 ratio (2:1), meaning that for 15 psi of intake manifold pressure there will be 30 psi of exhaust pressure.  When coupled to the correctly sized compressor wheel, the usually means a very quick spooling turbo (as the TGP does have. JM), but the engine will be choked up and the hp limited.  High exhaust back pressure makes it harder for the cylinder to push out all the exhaust gases and can even cause a reversion where some of the exhaust gases travel back into the cylinder (limiting the amount of the fresh air charge trying to come in. JM). As we start to use a more efficient (larger) turbine wheel and properly matched turbine housings, we will also notice a drop in the back pressure, and will also notice that the boost is now coming on slower and is not as responsive (initial signs of turbo lag, not bad enough to complain about. JM).  The trend is associated with an increase in horsepower depending on the compressor wheel.  From my dyno testing experienced we can be at a 1.5:1 pressure ratio and still make good power (good power meaning lag is not objectionable and hp is up in line with the output of the compressor wheel/size,  JM).  The best tool for measuring the relationship of backpressure, horsepower and spool times is of course the chassis dynamometer (of course. JM).   On the dyno is where we can really start to match up components of the turbocharger for its optimum performance.  Starting at lower boost levels and working up towards a point where the turbo (compressor side) is running out of flow and/or just not making more hp, we compare the dyno charts and exhaust backpressures.  Lets say we know the compressor wheel and engine combination (no bottle necks) we are using can support around 450whp and we are only making 300whp with a 2.5:1 exhaust to intake pressure ratio.  We now realize that the turbine side of the turbo is undersized and/or the compressor is oversized.  Assuming that we set the 450whp as our goad, we are going to modify the exhaust side to meet our demands. The simplest test would be to install a larger A/R turbine housing and see if our hp improves and the pressure ratio becomes closer to 1:1.  If we see an improvement then we have made a step in the right direction.  However, if there is little or not change then we need to look a larger turbine wheel.  There is a point of diminishing returns in which we can start to up the turbine side and drop the exhaust backpressure but the compressor wheel will start to run out of flow and the turbo will become less responsive ( ?well if the turbo is good for 450 hp and you are not making 450 hp yet then you are not running out of flow, the only concern is what level of turbo lag is acceptable as you progress up in your tests.  JM).  This happy medium of maximizing the compressor wheel, reducing the exhaust back pressure and quick turbo response is a fine balancing act that takes time (GOOD POINT, Not as easy as just grabbing a great turbo with good numbers!!  JM).  In the end though, it?s well worth the effort!? (END of magazine quote).

Now if anyone gets this magazine, the power graphs are not as meaningful for us since they started with a turbo that was better sized than ours when the boost is raised past 12 psi (there is still a good amount of backpressure at 10 to 12 psi on the stock TGP turbo, where a better turbine housing and/or turbine wheel would make some good hp gains to those stock turbos!).  Also note they did not mention, or test larger down pipes/exhaust systems, the turbo is the biggest and most common restriction to work on, and it can require quite a few wheel and housing changes and tests to achieve the desired results! Once a proper turbo setup is found that has the least amount of restriction it can be and not cause excessive turbo lag while still offering a compressor wheel running in its best efficiency range, then upgrading the down pipe and exhaust system is all free power, as long as your compressor wheel is able to provide the hp asked of it by the boost settings or more accurately, the lbs of air flowing, as boost is NOT the true indication of air quantity/quality getting into the combustion chamber, but more so an indication of it backing up in the intake manifold as boosted air struggles to get through the lower intake manifold, head ports and valves!  Do some thinking on this?..if you can get more volume/exhaust out of the engine with less backpressure, then there is less pressure left over in the engine which will allow more fresh charge air in, but for the same work the turbo is doing now, the boost will actually drop some (all things being equal) as the air is not backing up trying to get into the combustion chamber since it is not left with a lot of exhaust backpressure there, and if the turbo is not working as hard, its more likely to be in its sweet spot of highest efficiency, also lessening the work the intercooler has to do as well.  There is a lot of things to think about and juggle as these details are worked out, and these last 2 long sentence are something to digest for those wanting learning.

Jeff M