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Dyno results - 293hp/302tq - comments?

Well - went to the 928 gathering at Howard's place on Burford Hwy this Saturday. Lamar Automotive across the street was offering dynos for $40. The first two runs were at 16 lbs boost and the last was at 17. This was run on pump gas - 92 octane. I swapped out the modded end tank intercooler for a stock one for the last run. Some one had mentioned in my previous dyno thread over on rennlist that maybe I had a restriction there.

http://forums.rennlist.com/rennforums/showthread.php?t=444674

I don't think that made a difference though - a/f curve stayed the same and the increase in hp was from the increase in boost. Mods that are relevant are 60-1 HIFI with a Stage V turbine wheel, mildly ported polished o-ringed head, widefire, 55lb injectors, 3 bar FPR, Vitesse MAF and chip board, 38mm tial, 3 inch SFR exhaust from downpipe back, lindsey intake, godzilla blow-off and modded intercooler.




I was hoping for a little more than the typical 10hp/lb boost. I guess the limiting factor on this engine right now is the turbo. I figure one day I'll run down there with a stock intake on and see what difference that makes.

Some please let me know if i am wrong but it seems like there is not a lot of hp to be gained by leaning out the fuel curve? Seems like I am running pretty steady between 11.5 and 12.
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Old 09-08-2008, 06:14 AM
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how are you controlling the tune? there's some power to be had by leaning it out, but there's more power to be had by advancing timing if you can do that. this was from my testing by going to 13:1 afr to see if the gains were worth it.

you should be making more power sooner with a 60-1 hifi. do you know what size the hotside is?

it also seems to be lagging (full boost by 4000rpm?).

are you sure you don't have any exhaust leaks between the exhaust headers and turbo?
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Old 09-08-2008, 08:21 AM
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Quote:
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how are you controlling the tune? there's some power to be had by leaning it out, but there's more power to be had by advancing timing if you can do that. this was from my testing by going to 13:1 afr to see if the gains were worth it.

you should be making more power sooner with a 60-1 hifi. do you know what size the hotside is?

it also seems to be lagging (full boost by 4000rpm?).

are you sure you don't have any exhaust leaks between the exhaust headers and turbo?
Was hoping you would weigh in. I have no control on the tune right now but I do have an SMT6 to install that would fix that.

The hotside is an 8.

I don't think I have exhaust leaks - shoved a blower up the tailpipe the other day while the car was on the lift and I couldn't find any air coming from the headers and crossover.
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Old 09-08-2008, 09:35 AM
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ah one thing i missed, how are you controlling boost? does boost hold steady to redline without dropoff? the torque curve seems rather peaky.

have you checked cylinder compression lately? are you burning any oil?

it also looks like you have a mystery turbo. so i can't say for sure if that particular turbo should be spooling quicker, or what. do you know who built that turbo? how's the turbine wheel clearance between the blades and the housing? any gap there will allow air to leak, resulting in poor spool performance.
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Old 09-08-2008, 09:55 AM
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okay josh, i just read that thread and it seems you may have gotten a bum deal on a bum turbo. no amount of tuning is going to make up for a poor product.

with the amount of investment you already have into your other mods, it sounds like you might be a good candidate for a proper turbocharger upgrade.

if you're seeking cheap cost turbo upgrade for street use, i have heard you can now buy a k27/6 (or 8) for $600 (i have not been able to verify this), which will get you much better usable power.

if you want some real performance, you might have to step up to the double ball bearing garrett turbos, but those will run you around $1200 and up.

if you have the ability to get a broken turbo rebuilt (rebuild costs around $700 and it will get you a warranty), i have a stock kkk k26/8 from my 89 turbo-s with a broken/missing turbine that i am willing to give to you for free if you pay for the cost of shipping. you could then get this rebuilt to a k27/8 and have a turbo with warranty.
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Old 09-08-2008, 10:18 AM
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I just have a manual boost controller - seems to hold 17lbs to redline.

I've read your thread on the turbo reviews and am really tempted to pick up a turbo from Vic eventually. Which model did you end up going wth?

Compression is 130 +/- 5 across all four cylinders and while I do get a small amount of oil out the tailpipe under boost I don't think it is that far out of spec.
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Old 09-08-2008, 10:44 AM
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how are you monitoring boost? do you have an aftermarket gauge? does the dyno place have the ability to datalog boost?

i went with a t3/t4 garrett dual ball bearing center cartridge with a 50-trim compressor and #10 hot side. 18psi by 3k rpm on the stock 2.5 motor.

turbo upgrade - pauer tuning
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Old 09-08-2008, 12:48 PM
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Nize what is the stock turbo psi on an 86.I fixed my fuel issue but still seem to be losing boost somewhere I'm still hearing that hiss sound under the car under boost at part throttle it pulls good at wot it slows down and then the hiss starts
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stock turbo boost should be around 12psi. the stock setup also bleeds boost at higher rpm's so it won't hold to redline.

if you're hearing a hiss, your BOV might be leaking. you might want to start another thread with questions about your issues.
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Old 09-08-2008, 03:34 PM
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293whp at 17psi is nothing to sneeze at but I agree that theres more potential in this setup.

60-1 HiFi / #8 Stg V is a solid turbo IMHO. They're nothing special, but people have seen some great results with them in the past.

Also at 17psi on pump I would be reluctant to lean it out much more. But I agree that would pick up a few HP.

The things I would look at are:
Does the timing map on those chips match that turbo?
Who did that port and polish? (was it a garage job, or did they follow a tested protocol?)
Is the LR intake manifold really doing its job in this application?

There was a guy who ran a very similar setup to yours (same turbo and minor headwork) who eventually installed the LR intake manifold. In a back to back test, he lost power and ended up removing and selling it. I think those things are designed for engines with hogged out heads and big cams.
Old 09-08-2008, 10:58 PM
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Quote:
Originally Posted by nize View Post
how are you monitoring boost? do you have an aftermarket gauge? does the dyno place have the ability to datalog boost?

i went with a t3/t4 garrett dual ball bearing center cartridge with a 50-trim compressor and #10 hot side. 18psi by 3k rpm on the stock 2.5 motor.

turbo upgrade - pauer tuning
Just have a VDO boost guage in the dash. I don't know if that shop could have monitored boost or not - probably could.

Wow - 18 PSI by 3K would be awesome!

Quote:
Originally Posted by sickwidit951 View Post
293whp at 17psi is nothing to sneeze at but I agree that theres more potential in this setup.

60-1 HiFi / #8 Stg V is a solid turbo IMHO. They're nothing special, but people have seen some great results with them in the past.

Also at 17psi on pump I would be reluctant to lean it out much more. But I agree that would pick up a few HP.

The things I would look at are:
Does the timing map on those chips match that turbo?
Who did that port and polish? (was it a garage job, or did they follow a tested protocol?)
Is the LR intake manifold really doing its job in this application?

There was a guy who ran a very similar setup to yours (same turbo and minor headwork) who eventually installed the LR intake manifold. In a back to back test, he lost power and ended up removing and selling it. I think those things are designed for engines with hogged out heads and big cams.
I think that John claims that the Vitesse chips are setup to work with any turbo as it is a true MAF that actually takes an air reading and works off that?

Not sure who did the port and polish - I think Powerhaus. From what I could tell it is a light job. I have some 2.7 liter 47mm intake valves and I found a shop that can put them in for me and do a professional port/polish/o-ring at the same time.
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Old 09-09-2008, 05:09 AM
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I think that John claims that the Vitesse chips are setup to work with any turbo as it is a true MAF that actually takes an air reading and works off that?
it's technically impossible to have one chip that works with any turbo, because chips operate in open-loop mode with a set tune, and engine load characteristics change with different turbos, requiring a different tune (or a different chip). this applies to afm, maf, and map systems. the difference is how each system 'takes an air reading' but each system does actually take an air reading.

you could have a closed-loop system (ie; during partial throttle, cruising, etc.) that automatically adjusts the air/fuel/spark that works with any turbo, but that would only work during partial throttle. this is in fact the default factory setup and there's nothing special about it.

if you change the turbo, you must change the tune to match.

here is a good write up explaining the differences between afm, maf, and map, and how each takes an air reading;
http://www.zcar.com/forums/read/4/1520154
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Old 09-09-2008, 09:19 AM
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Excellent information found from Pro Max Motorsports :

AFM - air-flow meters are the crudest form of sensing devices. It uses a mechanical flapper barn-door that is physically pushed aside by the intake air stream. The volume of this air-flow then determines how much the door opens. The door then is mechanically attached to a variable-resistor assembly that then sends a variable-voltage signal to the computer that roughly correlates to the volume of air flowing past it. However, there are some disadvantages to this method:

* mechanical parts wear out - with age, the pivot on the door can bind, the spring loses tension, the resistor-array wears out.
* flapper door restricts air flow - this is kind of like the Heisenberg-principle of air-flow measurement, where you can't measure something without interfering with it. The spring-loaded door actually contributes to turbo-lag because at low-RPM, low-flow conditions, the door is almost completely closed. Then when you floor it, there's insufficient flow to fully open the door until more air volume is moving past it. But you can't get more air flowing without first getting more air into and out of the engine to build up boost-pressure, so it's a catch-22.
* Insufficient range for upgrades - the operating range of output voltages and the volume of air that corresponds to them are fixed by the physical dimensions of the AFM. If you turn up the boost or even get high-flowing modifications like an aftermarket turbo, there can actually be twice as much air flowing as a stock engine. What happens then is the AFM door will be fully wide-open by 4000rpm, and the output air-flow signal will be clipped (fixed) from then on. So the computer thinks air-flow isn't increasing, and puts out a fixed fuel-amount. However, the real air-flow really is increasing and the limited fuel will cause the car to run lean, detonate and blow up.
* Inaccurate air measurements - what really matters to the computer, is figuring exactly how many oxygen molecules has been ingested. But the number of molecules for any given volume of air changes depending upon altitude (pressure) and temperature. So additional air-temp. and altitude sensors are necessary to modify the air-flow signal received and compute an air-mass number. Which would then logically match up precisely with a corresponding fuel-mass/volume number for the injectors to meter. Which leads us to the next upgrade...

MAF - mass-air-flow sensors replaces the mechanical measurements of the AFM with an electronic version. MAF-sensors use active analogue electronics to measure current flow through a heated wire placed in the air-stream. As air flows past the heated wire, it cools the wire, with more air cooling the wire more. The circuit then pumps more current through the wire to keep its temperature constant, with more current required for more airflow. This current then drives an output voltage to the stock computer. One nice thing about the MAF-sensor over AFM is that air-temperature and pressure compensation is automatically included in the output signal. Denser/cooler air will cool the hot-wire more, and a higher voltage will reach the computer to indicate larger numbers of molecules flowing into the engine. As good as this is, MAF-sensors also brings along with it some of the same drawbacks as AFM-sensors and adds some new ones of its own:

* Insufficient range for upgrades - since there are physical dimensions to a MAF-sensor such as diameter and length of wire, the range of air-mass that it can measure is finite. A sensor that's roughly the same size as the stock AFM will measure roughly the same amount of air for the same output voltage ranges. Turning up the boost with a larger turbo will max out a MAF-sensor and it too will send out a clipped fixed signal to the computer. Going overboard to a sizus-maximus MAF-4 sensor to closely match your maximum air-flow with the maximum output-voltage ends up causing low-flow problems. You get an idle that is irregular, stumbles or dies completely. Or the mixture is so rich at idle, you'll never pass emissions; there are people who remove and re-install their MAF kits regularly just to pass emissions!
* No ignition-compensation for air-temperatures - while the MAF-sensor may include air-temperature compensation into its air-mass output to the computer, the issue of ignition control is not addressed. MAF kits typically simulate the air-temp signal line to the Motronic DME computer with a fixed voltage, thus fooling the computer into thinking that air-temps are always 60 or 70-degrees. However, the stock computer actually does quite a bit of ignition-timing modifications based upon ambient air-temperatures. In order to operate optimally at the highest levels of performance, ignition must be adjusted for the conditions as well.
* Inadequate fine-tuning controls - the output curve of a MAF sensor isn't quite exactly the same as an AFM for the same air-flow patterns. And upgraded cars with increased boost have air-flow patterns that are completely different than stock; typically less flow down low due to increased turbo lag, yet more flow up top. So a way of massaging the MAF-sensor's output is needed to 'fool' the stock computer into injecting an appropriate amount of fuel across the entire RPM-range and load-ranges is needed. Some MAF kits use custom chips to provide this correction. However, unless your car has exactly the same turbo, with exactly the same boost curve and exactly the same intake & exhaust, not to mention internal wear and tear as their model car, your air-fuel mixture most likely won't be ideal. Other MAF kits include a four-knob signal-massager that tries to encompass adjustments across all possible flow & load ranges. This is a valiant effort, but much too coarse to allow tuning a car for maximum performance. Which brings us to...

MAP - manifold-absolute-pressure (also known as speed-density) measurements combine simplicity in sensor design with the power of digital microprocessors to compute a simulated volume-air-flow signal that is sent to the stock computer. As shown in the following diagram, you can completely replace the entire stock AFM-sensor (or upgraded MAF-sensor) and their associated wiring with a simple vacuum hose. As far as the stock computer's concerned, it's seeing the signal from an actual stock Air-Flow-Meter. Thus the computer will inject the appropriate fuel-volume to produce the highest power possible. This MAP-sensor upgrade kit doesn't suffer from any of the drawbacks of AFM- or MAF-sensors and has some unique benefits as well:

* No mechanical parts to wear out - this provides the best durability and longevity possible. Even MAF-sensors can suffer from contamination of its hot-wire (due to turbo-oil blow-by).
* Air-temperature based ignition control - an air-temp sensor is included that plugs into the stock AFM harness to provide computer with an accurate measurement of ambient temperatures.
* No flow-limits - since it is programmable, the AFM-Link unit will always linearly scale its output signal to fall within the 0-5V output range of the stock air-flow-meter regardless of whether it's installed in a bone-stock 951 with K26/6 turbo @ 12psi boost, or on a track-monster with K45/19 @ 57psi.
* Extremely fine adjustability - using non-volatile RAM memory to store all of its settings, this unit can be used to output ANY kind of an output air-flow map to ensure proper air-fuel ratios under all RPM and load-ranges (adjustments can be +/-127% in 500rpm increments).

Note that this isn't a piggyback-style signal-interceptor/massager like the Split-Second ARC-2, Apexi AFC, HKS AFR or the UNIchip. Those units sit in between the stock AFM or an aftermarket MAF sensor, intercepts and massages their outputs to fool the computer into thinking air-flow conditions are something other than what they really are, thus the computer is tricked into injecting less or more fuel to compensate.

The AFM-Link box (used in ProMAX MAP kits) is the actual sensor itself that generates (from scratch) an actual air-flow signal to the computer, rather than simply intercepting and massaging an existing signal from some other source.

Due to its advanced digital micro controller-based design, the AFM-Link fuel-computer is a fully self-contained unit that includes a MAP-sensor and the digital electronics to compute a simulated air-flow signal that closely matches ANY and ALL actual flow conditions. It can create non-linear discretely mapped fuel-curves to give you precise fuel-metering under all conditions.
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Last edited by nize; 09-09-2008 at 09:33 AM..
Old 09-09-2008, 09:30 AM
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Great reading but what is all this we read on rennlist from a vendor no mater what boost you run if you have his MAF AND Chips AFR will be bang on fact or fiction?
Old 09-09-2008, 12:40 PM
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Great reading but what is all this we read on rennlist from a vendor no mater what boost you run if you have his MAF AND Chips AFR will be bang on fact or fiction?
where is this claim? do you have a link? maybe start another thread for this tangent discussion.
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Old 09-09-2008, 12:46 PM
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this has been a claim from this vendor for years with his MAF Chips AFR will be good to what every boost you run fact or fiction? That's all I am asking . I think it is very relavent. His MAF might be maxed out?
Old 09-09-2008, 01:22 PM
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this has been a claim from this vendor for years with his MAF Chips AFR will be good to what every boost you run fact or fiction? That's all I am asking . I think it is very relavent. His MAF might be maxed out?
if you understand the mechanics behind how MAF and chips work, you will know this would be impossible. i'd be surprised if there really is such a claim.
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Old 09-09-2008, 01:47 PM
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So these claims that this vendor makes are false, that this brand of MAF and chips can not give good AFR what ever boost you run?
Old 09-09-2008, 02:01 PM
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heheh, you keep saying there is a claim, but i haven't seen such a claim anywhere yet. where is proof of this claim?
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Old 09-09-2008, 02:22 PM
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what's up Josh!
I know it has been a while since my last 944 turbo car but i wanted to chime in with some advice. Based on your thread on some "other " board it looks like you may not have a very efficient turbo to match up to the VE of your 951. I would say don't ditch the Turbonetics unit, rather just send it in to have a proper compressor wheel installed and choose a A/R that fits your engine build. My friend Dave turned me on to a huge turbo rebuilder in the US that does alot of trick stuff for reasonable prices. I sent in a KKK turbo to build a hybrid and it cost me half of what I was willing to pay. PM me offline and I'll share the number / name with you. If you are not sure where to go in terms of selecting compressor wheels they can do it for you based off of your engine data. I think this will give you what you are looking for... No sense in tosing a turbo that you already bought, you can turn that "super revolving disco potato" into a gem using the latest garret wheels for not alot of $$$...

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