Guys with superchargers get in here

[striped]

I have a few last minute questions I need to get out of the way. First, if you still have your 7.5 rear end how's it holding up and what gears are you running. What gauges are you running? I'm thinking about going with boost and fuel pressure gauges, are these probably the best to use? Should I use only synthetic oil now, or is that more hype then fact. Dose any one have a link of a how to on Roush side exhaust? How much back pressure if any is needed to make the highest HP and TQ numbers? If you have the MAC long tube headers how much of a power increase did you notice? And last but not least....what race have you had that your most proud of

EDIT: i forgot something, I know this might sound kinda dumb but could a gt rear end out of an 89 gt fit my car....i mean its all the same platform right???

chris

 

[Blown3.8]

I have an Auto and my 7.5 is holding up great..im using 3.73 gears and Tlok.
Im using autometer boost and fuel pressure gauges.
I was running 2.5in side exit exhuast but i just switched back to rear exit 2.25 because i had no low end in my auto(no high rev) so i opted for the low end .

best race to date hmmm i loved them all i belive i won 90% of them last year.

 

[GREENBIOCH]

Blown how many miles do you have on your car??

I'm doing a head/cam swap before I supercharge it? I have been contemplating a rebuild of the bottom end first with the head/cam swap or maybe before/after the head cam swap depending on how this leak down and compression test goes.

I guess I'm trying to get a feel for how tough our cars engines are, I have close to 100k miles on it and starting to worry about building it up.

 

[marvinmycat]

I may be wrong, but I thought the 89 rear end is an inch longer than our SN95's. I read that somewhere, but don't recall exactly where.

 

[Blown3.8]

I just hit 85k on it yesterday

 

[98CobraClone]

Coming up on 79,500 miles on mine. Still stock rear 7.5 with airplane gears. I don't hammer into it from takeoff or have hard launches daily, so that will definitely extend the life of your rear.

I have two A-pillar gauges. boost and water temp
2 gauge cluster gauges - fuel pressure and A/F (yeah, I know it's a waste)

I have side exhaust and I can tell you it's a PITA to get a dyno tune with it......

 

[atlblue2000]

I'm running the same pillar setup as CobraClone is and will be putting oil pressure and ??? in the instrument cluster pod.

I'm running stock gears, stock open diff, blah blah and it seems to be doing fine, although I know for a fact I wont come close to numbers like Cobra put down, especially trq-wise. If you have a 99+ mustang, save your $$$ on the FPG and just get a Jegs guage and plug it into the shraeder valve on the rail.

The LT headers will probably be worth a decent amount of HP/TRQ being blown. That will be my next mod for sure.

The fox rearend is shorter than ours. Also, if you decide to use it, I'd most definitely convert to a five-lug rear disc setup out back before you bolt it on.

I ripped my stang the other day and saw about 7.5 psi @ 5K... Not alot, but that 7.5 psi felt pretty darn good.

Don't concern yourself with backpressure, its exh velocity that you need to focus more on. I'm still running 2.25" piping, probably will go 2.5" when I get the LT in preparation for a full-on H/C/I combo.

 

[striped]

ya i didnt even think about the older gt rear having only 4 lugs.....

Blown3.8, how much low end did you lose with side exhaust, i mean alot or just a little.

atlblue, so if really wanted good velocity i could go from the LT headers straight to 3in. exhaust out the side? and like blown3.8 said, he lost low end, would i?

thanks for the help guys

chris

 

[atlblue2000]

3 in would be overkill. Remember, bigger isn't alsways better. 2.5" exh piping would give you a good combination of exh flow and velocity. While the 2.25" might not flow as much, it may flow faster thereby preserving your bottom end. The 3" on the other hand would flow bobs of exh but there would be so little velocity in it that you would be drastically shifting your powerband up top. Make sense?? It would stand to reason that the more air you can flow the better, right? Well, not necessarily. That's kinda the same principle that we apply to the bigger TB. Velocity is crucial when you are trying to find the best compromise of low end and high end power. My advice to you would be to start out with the LT and 2.5" and if your SOTP and the dyno both tell you that you are a little down on the bottom end power, then consider a trial run with 2.25" and see if your stang likes that better.

 

[striped]

3 in would be overkill. Remember, bigger isn't alsways better. 2.5" exh piping would give you a good combination of exh flow and velocity. While the 2.25" might not flow as much, it may flow faster thereby preserving your bottom end. The 3" on the other hand would flow bobs of exh but there would be so little velocity in it that you would be drastically shifting your powerband up top. Make sense?? It would stand to reason that the more air you can flow the better, right? Well, not necessarily. That's kinda the same principle that we apply to the bigger TB. Velocity is crucial when you are trying to find the best compromise of low end and high end power. My advice to you would be to start out with the LT and 2.5" and if your SOTP and the dyno both tell you that you are a little down on the bottom end power, then consider a trial run with 2.25" and see if your stang likes that better.

Thanks
chris

 

[SpectorV]

make sure its dyno tuned by a very good place not some little import dyno shop.... and if you got the right parts you should have no problem unless you rag on it non stop of course. the 7.5 will be fine until you try to hook up at the track, if you plan to launch hard get an 8.8

 

[Blown3.8]

when i was stock i could feel the power at 3k with 2.25 with the 2.5 i could feel it at 4 it sucked.