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Discussion Starter #1
I have the on3 70mm kit for my 94 cobra. I want it to last more than a summer with the stock bottom end. Right now I have the WG set up for 12psi but am thinking maybe back it off to the 10psi set up. I would like to see 450-500rwhp with the downpipe open.

My set-up, the main stuff

Blueprinted 92 shortblock
GT40 heads (completely worked over flow about 220-230cfm on the intake)
xe276hr cam
cobra intake, polished lower
ARP Head studs w/9333 gaskets
70mm tb
60# injectors
255lph intank plus trex
 

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Its hard to say. If it were mine I'd have it tuned. Run the lowest boost possible to get to 450rwhp and stop there. Lots of guys running more with no problem. Others have not been so lucky. You just never know how far you can push a stock block car. 4.6psi and 497 rwhp split my nice new 331 right down the center in under 100 miles.
 

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12psi is a bit much for the stock block; I run the smallest wastegate spring alone (4psi) and have a simple $20 Ebay manual boost controler. I have this set at 7psi under full load in 3rd gear (AOD). Not sure on the HP, but feels like 400-450ish. I'll have a 1/4 mile time in the next month or so. Maybe a dyno run, just to be cool.

I would not run more than 7-8 psi if you want to keep the stock block alive.
 

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Discussion Starter #6
12psi is a bit much for the stock block; I run the smallest wastegate spring alone (4psi) and have a simple $20 Ebay manual boost controler. I have this set at 7psi under full load in 3rd gear (AOD). Not sure on the HP, but feels like 400-450ish. I'll have a 1/4 mile time in the next month or so. Maybe a dyno run, just to be cool.

I would not run more than 7-8 psi if you want to keep the stock block alive.
How the hell are you tuning your car after you put a turbo on without dynoing it? Please don't say a wideband and street pulls...

Lowest boost setting is 6 then 8,10,12 for my kit. I guess just trying to see if 10psi will make 450whp with my set up.... I know there is only one way to tell, but just trying to see what everyone thinks.
 

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How the hell are you tuning your car after you put a turbo on without dynoing it? Please don't say a wideband and street pulls...

Using a Quarterhorse and entering known settings for my injectors and MAF. Yes I did tune it from driving around under normal conditions, not on a dyno. I made sure the timing and fuel were safe before going into boost.

In fact my wastegate was hooked up wrong and I was seeing 15psi a few times, lucky I had safe fuel and timing figured out. Now I have the smallest wastegate spring in the gate and adjust it accordinly; currently at 8psi.
 

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Its hard to say. If it were mine I'd have it tuned. Run the lowest boost possible to get to 450rwhp and stop there. Lots of guys running more with no problem. Others have not been so lucky. You just never know how far you can push a stock block car. 4.6psi and 497 rwhp split my nice new 331 right down the center in under 100 miles.
So you are saying you would want to run low boost and a bunch of timing on pump to reach your hp goal? That mindset is probably why your 331 didnt last. Makes more sense to run 2-3 more psi and bring the timing down.




12psi is a bit much for the stock block; I run the smallest wastegate spring alone (4psi) and have a simple $20 Ebay manual boost controler. I have this set at 7psi under full load in 3rd gear (AOD). Not sure on the HP, but feels like 400-450ish. I'll have a 1/4 mile time in the next month or so. Maybe a dyno run, just to be cool.

I would not run more than 7-8 psi if you want to keep the stock block alive.
Quit being scared.
 

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Discussion Starter #9
So you are saying you would want to run low boost and a bunch of timing on pump to reach your hp goal? That mindset is probably why your 331 didnt last. Makes more sense to run 2-3 more psi and bring the timing down.






Quit being scared.

That is my thinking, or at least the way I am leaning toward is running 12psi and running a conservative tune to get the power. Instead of low boost and pushing the tuning.
 

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That is my thinking, or at least the way I am leaning toward is running 12psi and running a conservative tune to get the power. Instead of low boost and pushing the tuning.
A hot tune is just that, no matter what boost level. :salute:
 

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So you are saying you would want to run low boost and a bunch of timing on pump to reach your hp goal? That mindset is probably why your 331 didnt last. Makes more sense to run 2-3 more psi and bring the timing down.






Quit being scared.
You've got it all wrong. I was only running 20 degrees of timing and the smallest spring that came with the kit in an effort to keep that power at a level we felt was safe for a stock block. With the 8psi spring in the WG the car made 500 rwhp at 4,000 rpms. We put in the smallest spring and puled the timing back to 20 deg total which was the lowest the car liked. On the 5th pull it made 497. This was as safe tune possible. The timing was not a factor in what happened to the block.

I was advising the OP to only run enough boost to get to 450rwhp. I dont think he will need 12psi to get 450 from his set up. Anything over 450 is a crap shoot.
 

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I can tell you this much. I ran 9 and 13 lbs on a bone stock 95 Cobra. I had it tuned and everything and it made 413 / 525 at the wheels on 13lbs. If it wasn't for my tinkering and me frying the Digital 6 I'm sure it would have lasted quite a while. I am planning on running 13 lbs again with my new setup. Hoping for 450 / 550 at the wheels this time.
 

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Discussion Starter #14
I can tell you this much. I ran 9 and 13 lbs on a bone stock 95 Cobra. I had it tuned and everything and it made 413 / 525 at the wheels on 13lbs. If it wasn't for my tinkering and me frying the Digital 6 I'm sure it would have lasted quite a while. I am planning on running 13 lbs again with my new setup. Hoping for 450 / 550 at the wheels this time.
Thanks for that input! I really might need the whole 12psi to hit 450 then.
 

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Id rather run the lower boost level and more agressive on the timing. Much more efficient and you waste less fuel.

Just because someone blows their motor up by going to agressive on the tune is their own fault for not tuning it right, you cant blame the methodology behind it, its no different that somone blowing their motor up with more boost.

Your tune is either safe of its not.

Not that it really matters, itll make the power whichever way you go, less boost more timing or more boost and drowning it in fuel and pulling timing.

So its up to the person with the car.

Not too good IMO when you got your motor all jacked up with boost and got it pig rich and hardly any timing in it and you get waxed by a similar setup running less boost and a real tune in it.
 

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Discussion Starter #16
Id rather run the lower boost level and more agressive on the timing. Much more efficient and you waste less fuel.

Just because someone blows their motor up by going to agressive on the tune is their own fault for not tuning it right, you cant blame the methodology behind it, its no different that somone blowing their motor up with more boost.

Your tune is either safe of its not.

Not that it really matters, itll make the power whichever way you go, less boost more timing or more boost and drowning it in fuel and pulling timing.

So its up to the person with the car.

Not too good IMO when you got your motor all jacked up with boost and got it pig rich and hardly any timing in it and you get waxed by a similar setup running less boost and a real tune in it.
Yes you could have a safe tune with more timing, but you are going to be closer to that edge... What happens if you get some bad fuel or something along those lines? You are more likely going to have MAJOR issues when you are closer to that line.
 

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Id rather run the lower boost level and more agressive on the timing. Much more efficient and you waste less fuel.

Just because someone blows their motor up by going to agressive on the tune is their own fault for not tuning it right, you cant blame the methodology behind it, its no different that somone blowing their motor up with more boost.

Your tune is either safe of its not.

Not that it really matters, itll make the power whichever way you go, less boost more timing or more boost and drowning it in fuel and pulling timing.

So its up to the person with the car.

Not too good IMO when you got your motor all jacked up with boost and got it pig rich and hardly any timing in it and you get waxed by a similar setup running less boost and a real tune in it.


Just do 11.5 a/f with moderate timing. Doesnt have to be pig rich with no timing. That wouldnt make any sense.
 

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How the hell are you tuning your car after you put a turbo on without dynoing it? Please don't say a wideband and street pulls...

Lowest boost setting is 6 then 8,10,12 for my kit. I guess just trying to see if 10psi will make 450whp with my set up.... I know there is only one way to tell, but just trying to see what everyone thinks.
there is absolutly no reason you cant tune on the street with a wideband and a dataloger. its the same as doing it on a mustang dyno. what do you think happens on a dyno, you make a pull tuner reads the screen and makes adjustments to airfuel. so you go on the street start small make pulls in forth gear read your dataloged info on the same screen the tuners use, make adjustments until its right. dont get me wrong dynos are nice for fine tuning and tweeking, but not necessary.
 

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Yes you could have a safe tune with more timing, but you are going to be closer to that edge... What happens if you get some bad fuel or something along those lines? You are more likely going to have MAJOR issues when you are closer to that line.
Thats the difference b/w a good tune and one on the ragged edge like you speak of. Somoene who knows whats going on is going to pull back a few degreess from MBT timing and parhaps richen it up a slight bit, to have a small cushion for things like bad gas and the like.

But IMO i dont think purposely adding boost with the intention of runing really conserative on the timing to make the same power that can easily be made with less boost and more timing and still be "safe"(which is what i think you meant) is the ideal way to do things, not that it wont work. Just IMO the whole idea is to do more with less.

Ive just seen and read where guys are running timing locked at 15* and running AFRs deep into the 10s calling this "safe" Its just wasting fuel and killing power.

to me a SAFE tune is a tune that doesnt detonate and blow your motor under the conditions its going to be put under and account for the bad tank of fuel like stated before. Its either safe of its not, once you account for the small margin error like on bad fuel and stuff you should be golden.



As for the tuning, wideband tuning on the street works great. You can load the car just as much as a dyno can, a dyno works great and you can do alot of tuning fast, but the WOT tuning is the easy part. Its the low speed drivability is the hard part. and theres just some real world street conditions that cant be produced on the dyno, you always gotta fine tune things for the street.
 
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