Gooday, I am building a daily driver.. I would like my 0 to 60 to be fast... No drag racing, I rather auto cross or race on a track.
How much HP would north-star pistons in a 4.9 give me? would they create any issue down down the road?
what would the the delta cams 480 lift cam regrinds do for me?? will this make the motor vibrate more? will i see any issues down the road? 100,000 miles...
What other mods could i do? I will looking for ultra reliability but with around 250HP 350 TQ, using a 4 speed Muncie..
Who sells the 119? mm starter?
[This message has been edited by jeffdean42 (edited 03-12-2010).]
I don't think you will see those kind of numbers from a modified 4.9 unless you add a turbo or supercharger or something like that. Still, I have ridden in one similarly built to your description (except maybe the pistons) and it put a big smile on my face! I think the starter is a Nippon, but do some searches in our excellent archives, there is TONS of great info there.
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12:39 AM
stickpony Member
Posts: 1187 From: Pompano Beach, FL Registered: Jan 2008
Gooday, I am building a daily driver.. I would like my 0 to 60 to be fast... No drag racing, I rather auto cross or race on a track.
How much HP would north-star pistons in a 4.9 give me? would they create any issue down down the road?
what would the the delta cams 480 lift cam regrinds do for me?? will this make the motor vibrate more? will i see any issues down the road? 100,000 miles...
What other mods could i do? I will looking for ultra reliability but with around 250HP 350 TQ, using a 4 speed Muncie..
Who sells the 119? mm starter?
rick stewart did a rebuild, N* pistons, larger intake valves, P&P 'd heads, delta .480 cam, allante intake, on a 5 speed, and he got somewhere in the neighborhood of 235 HP and 330 TQ to the wheels, and that was in a highly untuned state running pig rich. if properly tuned, the wheel HP will be 250+ and the TQ right around 350, but that is pushingt he very limits of that motor normally aspirated. it would basically be maxed out, there would be nothing more you could do with it. the ONLY thing i would recommend to get more HP, is do all those mods, but without the N* pistons. use the stock 4.9L pistons and get a delta cam grind made for a turbo application instead of the .480 cam grind, and add a turbo with liek 4 or 5 psi boost, and tune it properly. it should light the street up something fierce.
[This message has been edited by stickpony (edited 03-13-2010).]
the ONLY thing i would recommend to get more HP, is do all those mods, but without the N* pistons. use the stock 4.9L pistons and get a delta cam grind made for a turbo application instead of the .480 cam grind, and add a turbo with liek 4 or 5 psi boost, and tune it properly. it should light the street up something fierce.
what a great idea... ;-)
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I don't think you will see those kind of numbers from a modified 4.9 unless you add a turbo or supercharger or something like that.
Really? You realize the 4.9 is rated at 200hp 275tq from the factory? Do you also realize that most swaps into a fiero produce more power then that? I suspect this is partially because of the intake and exhaust changes needed. A manual trans will also allow more power to reach the ground. It also seems that the 4.9 was one of those engines that was a bit underated from the factory. fourpoint9 here on the forum recently dyno'd his and got 217whp on a stock engine. IMO 250/350 is not at all out of reach for a NA 4.9 with a manual trans.
Northstar pistons will increase the compression ratio quite a bit. Not a great thing for a daily driver, especially one that already needs premium gas.
Build yourself a good intake. Properly sized exhaust system. Cam and port heads/intake/exhaust. Gasket match while your in there also. If you feel you need it some slight modification to the valvetrain could do some good. The 4.9 already gives a great 0-60mph time.
Really? You realize the 4.9 is rated at 200hp 275tq from the factory? Do you also realize that most swaps into a fiero produce more power then that? I suspect this is partially because of the intake and exhaust changes needed. A manual trans will also allow more power to reach the ground. It also seems that the 4.9 was one of those engines that was a bit underated from the factory. fourpoint9 here on the forum recently dyno'd his and got 217whp on a stock engine. IMO 250/350 is not at all out of reach for a NA 4.9 with a manual trans. [/URL]
No, I didn't know that was the factory rating. Most of these engines aren't rebuilt and after 100k miles aren't going to exhibit those kind of numbers anyway. I based my opinion on this post https://www.fiero.nl/forum/A...050119-1-046354.html and talking with a friend who has done the swap himself. By the way, Raydar says in that thread (regarding PBJ's turbo 4.9) "VERY impressive numbers. The previous best I've ever seen from a 4.9 was 170-something, through a manual tranny. This on an install based upon a crate motor, with a Rockcrawl chip." Although I do admit the thread is old, his opinion came from 5 years on this forum (now 11).
As far as the link you provided you can see that beside a quick spike in the results at about 220, the torque maxes out at 200. To get it to 350 nat aspir is a tall order in my humble opinion, but I'd love to be proven wrong. I'm sure it could be done if you wanted to throw a bunch of money at it. Although I do admit that 217 hp is impressive since nothing had been done to it, but I thought these motors were regarded more for their torque.
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09:56 PM
Mar 15th, 2010
Fieroseverywhere Member
Posts: 4242 From: Gresham, Oregon USA Registered: Mar 2006
I've seen a couple Dyno graphs in the 170/230 range also. Both of which were untuned and missing circuits. VSS circuit mainly. The 4.9 just doesn't work right without that signal and cuts power output. Same goes for 12v to the power steering input.
I'm not saying its the simplest task to make it happen. I'm just saying I believe 250/350 to be attainable without boost. What is really needed to take the 4.9 to the next level is aftermarket heads. The factory heads are the limiting factor is this engine. There is quite a bit of material that can be removed during porting but the overall design is still restrictive.
A rockcrawl chip changes nothing for the tune, timing, or fuel tables. He just sets them up to eliminate VATS and make other minor changes. There aren't many "tuned" 4.9's out there. This engine is cheap and usualy gets treated as such.
I think you read the dyno I posted wrong. I'm seeing the max torque, quite literally, off the chart above 275. Probably closer to 300. HP is always going to be lower. Thats just the nature of this engine. I'm not trying to start an arguement here just saying there is more that can be done and boost is not necissarily needed to achieve the numbers the OP is looking for.
No worries, and you are right, I read the chart incorrectly, but it is confusing, if you pause it, it says TORQUE on the right hand side and a line of the graph averages out at about the 200 mark but since the stated value on the screen is 217 HP, that must be the HP line and the other one obviously Torque. I did not know that about HP always being less than torque. That's why I love this forum, you learn new things all the time! I appreciate your comments about the 4.9, interesting stuff. If that motor goes over 300 torque now, than I agree it shouldn't be too much to get it to 350. I guess another thing that confused me a bit is PBJ's motor (now mine) uses a turbo to achieve 350 torque and he did quite a bit to it in addition to the turbo, cam, head work, intake, etc. But that was thru an automatic so that would account for some loss of power. I will have to do a dyno test some day and see what it does thru the manual tranny. What would you say loss is thru the automatic and thru a manual drivetrain on an engine in this HP range?
[This message has been edited by countach711 (edited 03-15-2010).]
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12:11 PM
Fieroseverywhere Member
Posts: 4242 From: Gresham, Oregon USA Registered: Mar 2006
I should clarify a bit... With this engine HP is always lower then TQ until you get above 5252RPM. As with any engine that is where the HP/TQ lines always cross. The 4.9 in particular has a very big difference in the lower RPM range. I happen to like its power range. I don't need to rev it to make power. In fact it produces more torque off idle then 95% of the engines I've played with. Mixed with the mid engine layout in a fiero gives you a car that can really jump off the line. Traction is the biggest issue but if you can control your right foot you can use every bit of what you have available. Its my favorite engine I've run in a fiero for around town. Racing is a different story. I don't feel the 4.9 has what it takes for drag, road race, ar any racing above 70mph. Does well in autocross though. Of course adding a turbo changes everything.
I'm not sure the exact numbers for loss through the trans. Best estimates I've heard are 15-20% manual and 25-35% auto. Each trans varies. Auto's also weigh more, sometimes more then double that of a manual. Having used all 3 fiero manual trans in my 4.9 I've come to the conclusion that the Getrag is the best compormise between mileage and strength. It "feels" like it puts more power to the ground but of course thats subjective. I'm not an auto guy so I have not idea there.
I did not realize you were mating that engine to a manual. Now I'm even more interested. I think most of the head work on your motor was to help out the upper end power. Most likely seeing a slight loss of low end torque in the process. I'd bet thats why your TQ was only 350. Still thats an increase of ~100hp and ~75tq from factory rating. Nothing to sneeze at. IIRC your intake was changed from stock before the turbo. It was necissary for the 7730 ECM. Its been a while since I read the threads (4 total I believe). I'll have to refresh my memory again.
I think most of the head work on your motor was to help out the upper end power. Most likely seeing a slight loss of low end torque in the process. I'd bet thats why your TQ was only 350. Still thats an increase of ~100hp and ~75tq from factory rating. Nothing to sneeze at. IIRC your intake was changed from stock before the turbo. It was necissary for the 7730 ECM. Its been a while since I read the threads (4 total I believe). I'll have to refresh my memory again. 
