JET951

I agree with you Dave, on the stage 3 and Gt3076 i do not know what the timming is. but the Gt3071 was tuned via a Motec. By a very reputable Tuner over here. As Rod has said in an above post he has since changed the turbo from the gt3071 and has got better results but none the less the stage 3 out performed them.

My point is. the Vitesse turbo is what i reccommend from the results we have seen. As you know we have results from a few different turbo's down here in my eyes they are comparable to a point. When someone gets on rennlist and asked what turbo should i use for my upcoming 2.5 project i will give them my honest answer. Best bang for buck is the Vitesse kits. the Turbo bolts on to the stock engine mount/ Xover and downpipe. Even the standard oil line fits. the only thing needed to be modded is the coolant pipe from memory.

Lets look at how much it costs to change to a Gt series turbo. you need to modify the engine mount or buy one of those Tial mounts. need new supply and drain oil hoses. the Xover needs to be modified, the down pipe needs to be modified and the cooland pipes need to be modified. Now you want to tune the car yourself. add in a standalone/ harness then the tuning that goes with it. it would cost at least 3 times as much as the Vitesse kit. Yet we have not seen the results yet to justify spending 3 times as much.

Now for the guys that love to tinker with their cars, changing out Turbo Specs and tunning the car all the time. then sure i can definatly see the benifit it changing to a standalone and a later turbo if you would. If your a guy like me that just wants to get the engine together, go racing and go fast you cant go past a Vitesse kit.
Sean

evil 944t

Sean,

I hear you and have no problem with your personal choices. I was just saying, becareful with the numbers because, you have EMS's, different tunes, cams, engine sizes, exhausts, headers(aftermarket vrs stock) etc.. to deal with..

I just wanted people to understand that these are not true back to back turbo and tuning changes only that yielded your posted results. If you were to put these turbos all on the same stock cross over/exhaust, same motor/car and only re tuned to optimize, then I would trust the numbers better.

Even though the 3071 was tuned by a well known tuner, who is to say the head, cam, header, etc.. was all working well together(they probably were) just making a point..

ps - Say hi to your Dad.. I might be back down there next summer(your summer).

elargentino

I need a relationship, dude.
You and I are not looking for the same things.


lolz

gt37vgt

the cars in seans post a similar enough to make comparisons but differnt enough for us to want more ..
we would love to see some logs with heaps of data .. timing O2 readout induction temp. egt pre turbine pressure etc

Thom

What cam/crosspipe/exhaust was Rod running with the GT3071?
Did the tuner listen for inaudible knock?

JET951

Hi Adam,
unfortunately we have no other data available for the cars. just some dyno charts.
Thom,
Rod was running a twin scroll Gt3071 with dual pipes and wastegates. Exhaust was 3 inch. Cam i am unsure but if it was not stock then it would be a slip in cam. Again i am unsure if the tuner listened for knock.
Sean

JET951

Hi Dave,
I can tell you that Patrick was running more timing then my own setup. Patrick was running E85 on one of John's aggressive Vflex Race timing maps(more advanced timing throughout the map compared with my non Vflex non race map), and about 7 psi more boost.

I think your right that to do an absolute real comparison all three turbo's would need to be used on exactly the same engine, but this is also my point, cost of conversion. i can't run those Garrett GT30 series on a stock Xover or downpipe. some one has to pay for that. what i am saying that if its 3 times the price the customer would expect 3 times the performance. But in our case the Garretts dont quite perform as well as the stage 3.

In a few weeks i will get our car back on the dyno and do a similar run to Patrick, 22psi and E85 at least we can compare the 2 cars side to side. with their slight different Modifications.
Sean

Thom

Hi Sean,
I think Rod mentioned in another thread that he saw more exhaust backpressure with the custom twin scroll cross pipe and turbo than with the the stock cross pipe, probably meaning the tuner did a conservative timing map to avoid knock, while the GT turbo could have strongly benefited from more advance?

I would be surprised if you get as good results with the E85 V-flex map with the GT turbo as with the Stage 3.
My understanding is that the timing map in the Vitesse software is optimised to work with a KKK-style turbine which makes more backpressure than a - pinch of salt please - "similarly-sized" GT turbine. If we cannot add advance to take benefits of the less restrictive GT turbine then the GT turbo won't push the engine to the knock threshold like the Stage 3 with the more restrictive turbine will, resulting in losses both in spool and peak power with the GT turbo.

Just thinking out loud here.

thingo

Any gt turbo is going to have a lot less backpressure than a kkk housing, twin scroll or open housing. Sean's turbo has a great curve, but the dyno doesn't show everything.

evil 944t

My point is, your running a fixed timing map and swapping turbos. If the map is for a gt35 and you put on a gt40, you may not have enough timing to move it so, it will show slow spool and same going the other way, the timing for a gt35 will be "x" and the swapping on a gt3071, it will not be timed right to provide quick spool and most imoprtant, your peak torque timing values will be off and you will not optimize your turbo.

I agree the costs of putting on a GT turbo are present(about $2000 for a bolt kit or cheaper for a DIY guy)but, for someone that wants to run a stand alone, I don't see the cost as a big deal. The turbo selection becomes very good and with billet wheels, etc.. you will not beat them. For +/- $4500 you can get a full standalone and gt turbo. That is not that bad.

fast951

The older software pre V-FLEX used static ignition. However with V-FLEX ignition is modified based on actual boost. When running the V-FLEX and the E85 maps you get ignition as close as you want it (and it is more aggressive than the ign timing Sean was running especially off boost).
In the above tests, Sean was running much more reduced static ( non V-flex) timing than with the V-FLEX E85 timing that Patrick was using. If anything Sean was at a disadvantage ignition wise, and was running 7psi less boost.

Even though Sean's results are outstanding, he was running 15psi vs. 22psi.. If Sean can dyno a 22psi run on E85, then it'll be a closer comparison.

I understand Patrick was using a aftermarket camshaft, which "should" have helped and not hurt his power output. Of course the performance cam on Patrick's engine will not be reflected in Sean's dyno. So it'll be as close of a comparison as it gets..

evil 944t

[QUOTE=fast951;8553399]The older software pre V-FLEX used static ignition. However with V-FLEX ignition is modified based on actual boost. When running the V-FLEX and the E85 maps you get ignition as close as you want it.QUOTE]

So, with Patricks version of vflex, are you saying the timing will advance/retard as needed to optimize any given turbo you bolt on? or There is "x" amount of timing loaded on a timing map and the map sensor and knock sensor will retard if it needs too? OR does the customer have to tune it themselves?

It was my understanding that Patrick could not adjust timing at all. Sean or Patrick, please correct me if I am wrong. I am assume the map selections are just different maps that are static and can only adjust between images when the map sensor tells it to. That being said, there is no way it can optimize for any given turbo.

Regardless of the version of Vflex or cam, these are not apples to apples comparisons, end of story. While they may be "close(and I doubt it), the results should not be taken as fact.

fast951

Timing is adjusted based on boost. The MAP sensor does not alter the ignition, the DME uses the value from the MAP sensor to alter the ignition timing. Same as a standalone (if it's configured to alter timing based on boost). No user intervention is needed!
Knock sensor works as always, if there is knock it retards ignition...

Dyno results are used for comparison purposes, dyno results are facts. As long as no one messed with the numbers or cooled the intake with ice or whatever before the run, the dyno results should be acceptable.

The theory that the ignition was too mild to cause the 100rwhp difference is not valid! Patrick's ignition curve is much more aggressive (not too aggressive to be unreliable, but aggressive enough to take advantage of E85). I'm just commenting on Sean's and Patrick's setups as I know the ignition curve for both.

Saying that you can gain 100rwhp by manipulating the ignition (at the RPM range where the difference is) is not something I agree with. Others may wish to believe it, based on experience I don't. At the same time, I will not say that the turbo is the "only" cause for the difference in HP/TQ. As a fact, a cam can push the power band to the right and can delay spool up. But it "should" raise the top end power (which I'm not seeing in the 22psi run).

If Sean runs E85 at 22psi, the comparison will be more "real". Hopefully he gets a chance to run it. It is not comparing apples to apples, it's not possible: The turbos and the cams are different...

evil 944t

Well, sorry to the original person who started this thread, I certainly went OT.

I see you didn't answer many questions so, I'll ask again, If the timing is "adjusted by boost", where/how does it know how much timing to use? At first you say that Patricks version of vflex alters timing to optimize any turbo and that it is different than a staic timing map of Seans version which is just burnt on the chip. Now it would seem as though your saying that they both do the same thing but, Sean's version just doesn't pull/add timing when needed. What I'm saying is, to my knowledge, neither of them had anyway to alter timing at all, otherwise they would have on Patricks car.

I'm not sure why your stuck on this 100rwhp rant when I am not disputing the over all numbers, I'm clearly saying that, timing will need to be advanced or retarded to optimize the different turbos that were tested. Surely, your map for your stage 1 kit isn't the same as the map for your stage 5 kit. Just as you have different maps for pump, race and E85. That being said, some of these turbos would have gained a good bit of performance which would not have had them look as if they are bad turbo choices.

Regarding the results of these cars on the dyno, there were 3 cars, many different head/cam configurations, different tunes, ems systems, exhausts, exhaust components, different dyno operators, times, temps, etc.. the numbers can easily be way off and that is if they were/are all running at their best.

Again, back to my main point, you can't call this a very fair comparison. It is great data and I thank Sean, Patrick and Rod for Sharing but, take it for what it's worth.

again, sorry to the OP

333pg333

Just to clarify, the pull that Sean is comparing on mine for the 290whp wasn't 22psi. I'm looking at a chart showing a number of pulls on the setup described with the larger '76, cam, exhaust, etc. The lowest psi is 20psi and the power figure looks to be about 295whp. The chart that Sean is referring to doesn't show boost or date. I'm pretty sure it's on the same date but not 100%.

When I was discussing the VFlex with John before I bought it, it was set up for a GT35. I then switched to a GT30 after receiving the VFlex down here. Not sure how much difference this makes as we can't read the ign maps or have control over them. Nor had I discussed cams with John or at that point thought I was going to change. The change in cam was my choice at a later date and while it's not a huge race cam, it's up from the OEM versions available. In retrospect I should have had John re flash the VFlex to suit these changes. I feel that the cam is pretty hampered by the n/a head with stock sized valves too.

Another thing that we found when on the dyno that day. The same person that has worked extensively on Rod's car also did some work on my car and was the dyno operator. He found that by increasing boost from 18psi up to 22psi there wasn't much overall gain. Perhaps 20whp overall. But there was a decent rise of 20whp between 4200rpm and 5300rpm when increasing from 20psi to 22psi. We were hitting our 'head' (puns intended) on something and his feeling was that it could possibly be the n/a head. Perhaps without the ceramic liners and a number of pulls we got some heatsoak in the head itself?

Also to mention that my car beat the lap records last year by quite a decent amount. Of course this wasn't down to any one factor, but if it was a laggy toad there is no way that this could have happened. A number of factors were responsible for the improvement. I'm sure the VFlex with E85 maps was one of them, along with the GT turbo. If you fast forward this clip to the 2.50 min mark you can clearly hear the turbo spooling well before it's getting into higher boost. While this is far from scientific, something is going on under that hood in the lower rpms and it's not the sound of me peddling! Perhaps it's the Ambulance behind me...


http://www.youtube.com/watch?v=M3kG4WDTN_c

So overall I'm encouraging Sean to do one more dyno session with his current motor before the 3L 16 goes in and raise the boost a up a few notches. In my eyes this still won't be true back to back comparisons but at least it will show what's available on some different cars on different days. There's no disputing that we are blessed in having alternatives at all for this forgotten car. Thanks to the vendors for making this possible.