What to do?

[DRock9]

I have the car in my sig and I just had it dyno'd, without the boost pipe, and put down 250whp/300tq with a very nice flat torque curve...when I put the boost pipe on I gained about 1.5psi so I guestimate I am at about 270whp/315tq right now but I am not sure. I have always compared my car to my friends 350z when I add mods to see how much they improove me, we go from a 40 roll to about 110 a couple times on the highway at like 2am...sometimes we go from a stop but since we both have SC's now we both just spin our tires if we gun in at all in 1st gear. Yea yea streetracing is bad but we do it very late when no cars are on the road and we do not go overly fast, and it is once a month if that.

Up until recently he has been several cars ahead of me but I recently found out my timing was 10 degrees retarded and it was SUPPOSED to be 10 degrees advanced...this was found out and fixed when I had it dyno'd. Well last night we went out at 2am and went from a 40 roll and we are dead even but since he has to shift I gain about a half a car until about 85mph then he starts to gain on me and eventually get to about 1-1.5 cars ahead at 100mph.

I was very suprised that my car could keep up with his because he put down 325whp/280tq on a Mustang Dyno which puts him at about 365hp/313tq on a Dynojet.

Is the reason I am losing due to gearing? He says as soon as he hits 4th he starts to gain on me, he has a 6speed so I am assuming he is just geared higher than me at 80mph.

I am posting this thread because I still have the stock gears on my car and I was wondering about how much I would gain on the highway if I were to switch to 3.73's or 3.55's.

He used to have about 5cars on me but then I gained 50whp when we advanced the timing which puts us at about dead even until 85mph...if I were to put in gears how much ground would that give me over him?

I am just using his car as a comparison as to how much faster the gears would make my car, we both have really fast cars and I do not care about beating him really because we are both friends and just do it for fun.

And I plan on eventually going up to 12psi with methanol injection so I would not want a set of gears that would just leave me spinning my tires to hell and back so I am thinking 3.73's would be too much.

It is either I do this for $500 or get a tune, a tune would net me about 20whp as I am running at about 10:1 AFR but I think gears would drop my time a lot more in the 1/4 mile so I am contemplating doing that instead.

Thanks for any help. I know it is a long read but I like to be as detailed as possible so that people can give me accurate insight back.

 

[grey5.0beast]

go with 3.73s and get decent tires. You should not have that big of a problem spinning with some DRs

 

[DRock9]

I daily drive this car so spinning on the street would be an issue, I think the stickiest tire I can get for the street and still be decent in the rain would be some Nitto DR's but I know they aren't the best for 60' times. I just want something that, with my suspension, will not spin or have very minimal spin in 1st gear when I mash the throttle from a roll. I will toss on some slicks for the track when I go there, but I can't afford to be stuck in the rain with Mickey DR's.

I know this is another weird question because gears don't actually give you horsepower or torque, but about how much HP/TQ would I have to add to my car so that it felt as fast as a 2.73 to 3.73 swap.

Thanks!

 

[grey5.0beast]

Well I doubt you would have that big of an issue mashing the throttle in 1st with some nittos. I have no clue about the amount of tq, but think of it this way, with that S/c making power up top 3.73s will get you into your powerband much quicker and give a huge SOTP difference. I went from 3.08s to 3.73s and I have no regrets at all. The car easily kicks sideways in second gear on the street, but with a better tire I am sure I would easily hook up and go. How much boost are you making?


And if you DD the car then just don't mash the throttle, ease into it if you feel like having some fun. Its not like DDing you will spin like you have 900tq on 225s...

 

[DRock9]

I am making about 6.5lbs at 5,500RPM, more like 7.5lbs at 6,250.

I think I might get some gears, but I don't know when I will be able to afford better tires...I just don't want to spin easy in 2nd, maybe I can adjust my shocks to compensate but with these tires I doubt it.

 

[emagdnim]

Only 250hp with an SC-Trim? I thought the good ol 5.0 responded better to boost then that.

 

[DRock9]

If I got it tuned it would have been at about 270...but meh.

 

[emagdnim]

I always figured you should be over 300rwhp with a supercharger on a 5.0.

 

[88mouse]

AFR is a little low. What injectors and meter are you running? Whats the timming set at?

 

[cenok is family]

Only 250hp with an SC-Trim? I thought the good ol 5.0 responded better to boost then that.

those numbers seem about right when you throw a blower on a completely stock motor with just exhaust. 250 to the wheels is still about a 50-60rwhp increase.

mindgame eh? you rollerblade?

 

[DRock9]

I am running the stock MAF with stock 19lb injectors, I am using the Vortech FMU.

If I can get my dyno chart scanned in I will, but it is nice at idle then dips right down to 10.0-10.5 the whole time until 5,500...I was thinking maybe if I bumped the fuel pressure up it would give me a better A/F because it is straight line the whole time with no spikes.

The timing is set at 10degrees advanced right now, the tuner said I MIGHT be able to get away with 11 or 12 but he doesn't reccomend it because the power I might get is not worth the risk...I think my timing chain might have been jumping a few teeth because he said when I got there and we did the first dyno pull it was at 10 degrees RETARDED!

My car was stock down to the air silencer when I got it

 

[ninety15.0]

Dam only 250 rwhp i would expect more from that. I before you do gears your money would be better spent ditching the crappy FMU and going with 30 or 36 pound injectors and getting a custom tune or a tweecer. 10.5:1 is still really rich...you would see considerable more power if you got those AFR's up to 12:1 or 12.5:1.

 

[DRock9]

Is 12.5:1 a good A/F with a blower?

I want to ditch the FMU but if I did that I would go 42lb injectors with a SCT2400 and up it to 12psi and maybe methanol injection.

I do not have the money for all of that right now so I want to stick with the FMU for now sadly

I was expecting about 270 to the wheels to be honest, but since I put the boost pipe in that should be about where I am at now.

I am not all that sad though because it keeps up with my friends 360whp 350z.

 

[ninety15.0]

I think that 12:1 is a decent place to start for a small blower combo. With only 6 psi and 10° timing...i dont think you are in any real danger at 12:1. Without a wideband you're not going to know whats going on though...and going back to the dyno everytime you change the fuel pressure or FMU settings is going to get expensive! Good luck man

 

[88mouse]

]I am running the stock MAF with stock 19lb injectors,[/B] I am using the Vortech FMU.

If I can get my dyno chart scanned in I will, but it is nice at idle then dips right down to 10.0-10.5 the whole time until 5,500...I was thinking maybe if I bumped the fuel pressure up it would give me a better A/F because it is straight line the whole time with no spikes.

The timing is set at 10degrees advanced right now, the tuner said I MIGHT be able to get away with 11 or 12 but he doesn't reccomend it because the power I might get is not worth the risk...I think my timing chain might have been jumping a few teeth because he said when I got there and we did the first dyno pull it was at 10 degrees RETARDED!

My car was stock down to the air silencer when I got it

That is killing it. And the AFR should be around 12.

 

[DRock9]

Thanks, I figured as much...maybe I will buy a wideband and an AFPR and tune it that way.