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Discussion Starter #1 (Edited)
I am running a T78 on Stock fuel, Stock IC, and I pulled the main cat on the dyno. I am also running VPC/AFC...
My first run was ~12psi and I dynoed ~340rwhp VERY RICH...
I went from 340 rwhp - 428 rwhp w/ 2psi in boost and leaning out the afc...
Is 428 rwhp kind of low for 1.03 kg/cm2 for a T78? Or is it the fact that I don't have a FMIC yet? My A/F was looking very nice on the last runs from tuning the AFC so I imagine that 426 is what it will make w/ the stock IC at that boost level.
any input would be appreciated.
regards
Roger
 

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Some boost controller tend to let boost drop a little by redline. At what RPM did you make peak hp and what was your boost at that RPM?

Later, Steve
 

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Sorry to butt in, I was watching the AVCR, it was holding 1.01-1.03 all the way till he let off.
 
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Right in line

You figure the T78 gets about 15rwhp per 1psi boost increase. 426rwhp at 1bar is low 600's rwhp at 2 bar----Which is what you'd expect on a car with no cams.
 

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Discussion Starter #5 (Edited)
dyno

Dre,
Hey there's Dre! Thanks for assisting me w/ the afc man..
Yea, I was watching my boost/egt gauges and it held strong 'till redline.
I came up w/ some solutions.. Stock intercooler got heat soaked b/c I ran the car for like 30-40 min. w/o shutting it down. Most back to back runs. Consistent 428 rwhp at least 4 times in a row.
I figure due to the heat soak the car could be making ~450 rwhp on the street. B/c it definitely feels faster than 426! My bpu was about that and this hits very hard now even w/ the cat on!
thanks
Roger
 

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I only dynoed 400rwhp @15-16psi of boost with my T78, stock IC, stock fuel and MAF. I am auto as too. I also think that heat soak from the stock IC was a factor. But I think that my air/fuel was really rich as well(did not have wideband).
SH
 
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rnitto said:
I am running a T78 on Stock fuel, Stock IC, and I pulled the main cat on the dyno. I am also running VPC/AFC...
My first run was ~12psi and I dynoed ~340rwhp VERY RICH...
I went from 340 rwhp - 428 rwhp w/ 2psi in boost and leaning out the afc...
Is 428 rwhp kind of low for 1.03 kg/cm2 for a T78? Or is it the fact that I don't have a FMIC yet? My A/F was looking very nice on the last runs from tuning the AFC so I imagine that 426 is what it will make w/ the stock IC at that boost level.
any input would be appreciated.
regards
Roger
what your doing is very very dangerous. Advise you in getting a fmic also the fuel syste.

Fefe Bag
 
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Re: Re: ~422-426rwhp @ 1.00-1.03 kg/cm2 :T78

Fefe Bag said:


what your doing is very very dangerous. Advise you in getting a fmic also the fuel syste.

Fefe Bag
for 428 rwhp?
 

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Re: Re: ~422-426rwhp @ 1.00-1.03 kg/cm2 :T78

Fefe Bag said:


what your doing is very very dangerous. Advise you in getting a fmic also the fuel syste.

Fefe Bag

ooohhh, never heard that one before...

People have dynoed 500rwhp on the t78 with stock fuel. But I assume your an expert on the whole T78 and stock fuel thing aren't you????? Jeesh!
 

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Re: Re: Re: ~422-426rwhp @ 1.00-1.03 kg/cm2 :T78

HoustonSC300 said:



ooohhh, never heard that one before...

People have dynoed 500rwhp on the t78 with stock fuel. But I assume your an expert on the whole T78 and stock fuel thing aren't you????? Jeesh!

hi houstonsc300
do u have any picture of greddy boost contrller installed to wastegate thanx





ken t78
 

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why is it that most of the time, people saying "your playing with fire, by running that single with stock fuel" have no experience with that setup. Its as if because they read it somewhere that its dangerous, they now have an opinion on it.

Of course its dangerous to run a large turbo on a fuel system that is limited to 550hp. Nobody is denying that. However, it can be done safely. Just make sure your hoses are ALWAYS tight, and use other tools, ie. egt, wideband, etc... to keep tabs on the vital signs of your engine. Other safegaurds would be to run 100+ octane, and an aftermarket fmic as well.

As for boost spikes, they are a rarity on the greddy type R wastegate. But I'm sure there is a possibility of having one.

all of this info has come from experience

:getting off soapbox: :)

chris
 

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Code:
I came up w/ some solutions.. Stock intercooler got heat soaked b/c I ran the car for like 30-40 min. w/o shutting it down. Most back to back runs. Consistent 428 rwhp at least 4 times in a row.

You should never dyno your car with pump gas without sufficient airflow to keep the temps down. Your IC can not keep the car from detonating in a static environment. The engine block itself heats up from the combustion and causes knock because there isn't enough airflow to cool the internal hot spots in the block through heat transfer.

My guess is that all your dyno charts start out with a smooth line then as boost climbed the line got really jagged. The jagged part of the graph is the ECU trying to keep the car from detonating by changing the ignition timing.

I accidentally picked up the wrong gas can once and put in 94Octane instead of 104Octane. I dynoed at 294rwhp and 342rwtq. After noticing the jagged lines on the dyno I mixed 114Oct and got 367rwhp and 417rwtq. All runs at 16psi with filter, exhaust and 16psi. (Same day same dyno of course)

Always try to dyno with race gas.
 

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Re: Re: Re: Re: ~422-426rwhp @ 1.00-1.03 kg/cm2 :T78

C5KILLR said:



hi houstonsc300
do u have any picture of greddy boost contrller installed to wastegate thanx





ken t78
Ken,
I have a couple pics of the stepping motor hoses, but they are vague. This one shows the stepping motor and the hoses routed to it...The hose that runs from the turbo, to the in on the stepping motor and then on to the side port of the wastegate, then a hose from the out port of the stepping motor runs to the top of the wastetgate. I put a T in pressure line(from turbo) to read boost pressure from it for the ProfecB. Hope that helps ken.
Scot
 
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