New Dyno Numbers! VMP TVS w/ ARH Longtubes

[greenflash00]

Well over the weekend I installed some 1 3/4 ARH longtubes with 3'' X-Pipe and today I went back to ProDyno to dial her back in. Very happy with the results I got! :rockon:

Final numbers were:
673rwhp on 93
724rwhp on e85
Pulley setup is a 3.2 upper/4lb lower on 93(19.5lbs-18*timing)
3.0 upper/4lb lower on e85(22lbs-20*timing)

Previous pulley setup was 2.8 upper/stock lower for pump and 2.6 upper/stock lower for corn which provided the same boost numbers as above new numbers.

From the last time I tuned it I picked up 20hp on 93 and 37hp on e85. Just added the ARH headers & X and 4lb lower kit but the boost was the same last time as this time. Same tuner, dyno, timing and about the same temperature within a few degrees. Soooo to answer the age old questions...YES! Headers do make a decent difference on these cars at higher levels. :thumbsup:

I went in hoping for about 710-715 and couldn't be happier. :coolman:

Video coming soon....epper:

 

[cj428mach]

So you're spinning the blower faster than before? Sounds like headers didn't do much at all then if I'm understanding your post.

 

[timspony]

Some pretty solid numbers :beer:

 

[b_dike]

How can you say that the headers made a decent gain if you also added a 4lb lower at the same time? Like stated above, your gains came from the 4lb lower. Not the headers... Either way those are good numbers. Gotta love that tvs on e85!!!

 

[greenflash00]

Previous tune was with 2.8/2.6 with stock lower which made (19psi/22psi). I went to a 3.2/3.0 upper with 4lb lower to minimize belt slip which also made 19psi/22psi.

 

[99riocobra]

My initial thoughts were the same as others, the difference came from the 4lb lower. That is good info to have though that you changed up the pulley combo all together really. Solid gains and solid numbers either way. Makes me want a TVS even more!

 

[greenflash00]

Ok either I'm totally missing something or doing a terrible job of explaining this lol....my goal here was to duplicate the same boost as my last tune to see what the headers gave me. I had some minor belt slip up top before so I wanted to change things up.... As a result I chose to use the 3.2 upper pulley and 4lb lower pulley to give me 19psi....which is the same boost I had with a 2.8 upper and stock lower on the previous tune. Likewise with the 2.6 upper/stock lower and 3.0 upper/4lb lower on e85. My thought was that duplicating the same boost level on both tunes would show the true header gains. Am I missing something or just really bad explaining myself? :lol:

 

[Brutal Metal]

673 on pump is Great for a 2.3 TVS congrats..

 

[Joe5.0]

Ok either I'm totally missing something or doing a terrible job of explaining this lol....my goal here was to duplicate the same boost as my last tune to see what the headers gave me. I had some minor belt slip up top before so I wanted to change things up.... As a result I chose to use the 3.2 upper pulley and 4lb lower pulley to give me 19psi....which is the same boost I had with a 2.8 upper and stock lower on the previous tune. Likewise with the 2.6 upper/stock lower and 3.0 upper/4lb lower on e85. My thought was that duplicating the same boost level on both tunes would show the true header gains. Am I missing something or just really bad explaining myself? :lol:

I understand, not sure why others don't. Awesome numbers man

 

[98 Saleen Cobra]

Well boost isn't a measure of power, it's a measure of restriction. What you really need to find out is blower rpm for the pulley setup before and after.. That will tell you if you the headers did anything..

Mind you I'm all about headers.. But you did it wrong. You needed to add the headers with the old pulley setup to see true gains. You don't keep boost the same to do the comparison as boost is a measure of restriction.

SO.. If the 2.6 upper only spins the blower to say 16000rpm and you made x rwhp.. Then you add long tubes.. Still spinning 16000rpm and you gain 40rwhp, that's headers doing the work.

Or if you did the same thing but then switched the pulley combo like you did and the 3.0 upper/4lb lower still equal 16000rpm for the blower then again the headers did the work.. I have a feeling you added the different pulley combo and now your blower is actually turning harder we'll say 18000rpm.. You did it based off of boost, and LT's drop boost as it opens up the exhaust side which allows less restriction...

Hope I didn't lose ya there lol

 

[cclark]

Very awesome op! I'm debating those headers and X, can't decide on 2.5 in collector with 2.5 X (inlet and outlet) or so what you did with a 3 in collector and 3 in X inlet and 2.5 outlet

 

[cclark]

Wait I see you have a MAC CB so you probably went 3 inch collector and full 3 inch X lol.

Also, anyway you could post new tq numbers? Curious to see tq with the addition of lower and headers with the same boost as last go round.

 

[greenflash00]

Well boost isn't a measure of power, it's a measure of restriction. What you really need to find out is blower rpm for the pulley setup before and after.. That will tell you if you the headers did anything..

Mind you I'm all about headers.. But you did it wrong. You needed to add the headers with the old pulley setup to see true gains. You don't keep boost the same to do the comparison as boost is a measure of restriction.

SO.. If the 2.6 upper only spins the blower to say 16000rpm and you made x rwhp.. Then you add long tubes.. Still spinning 16000rpm and you gain 40rwhp, that's headers doing the work.

Or if you did the same thing but then switched the pulley combo like you did and the 3.0 upper/4lb lower still equal 16000rpm for the blower then again the headers did the work.. I have a feeling you added the different pulley combo and now your blower is actually turning harder we'll say 18000rpm.. You did it based off of boost, and LT's drop boost as it opens up the exhaust side which allows less restriction...

Hope I didn't lose ya there lol

That's great info man thanks for posting that :beer: I was going off of the pulley chart from VMP's site and thought I would be keeping the blower rpm very similar with these two pulley configurations.I just thought the lower might help tq and belt slip a bit. According to this they looked to me to be accomplishing the same rpm (or close to it) Am I looking at this wrong?

Wait I see you have a MAC CB so you probably went 3 inch collector and full 3 inch X lol.

Also, anyway you could post new tq numbers? Curious to see tq with the addition of lower and headers with the same boost as last go round.

Haven't updated the sig yet lol...it's an SLP LM2 2.5'' cat back. Headers are 1-3/4 to 3'' collector with 3'' x. Torque was 575 on pump gas and 630 on e85. So it gained right at 15 ftlbs on 93 and 21ftlbs on corn. Lower than most TVS cars I see which I've never understood but oh well. My tuner said it makes great power but has a weird tq curve. Posted dyno graph up above to original post. :beer:

 

[CobraBob]

Glad that 98 Saleen Cobra posted those comments because he's spot on correct. The chart that you posted would be more complete if it showed blower speed and the affect of long tube headers on boost (psi).

But for what it's worth (not comparing apples to apples, of course), on an Eaton setup a 2.8 upper vs. a 3.2 upper & 4 lb. lower produces almost the identical RPMs (17,643 vs. 17,469). I don't know the source of the chart I am referencing, so the RPM comparison may not be spot on correct. It's probably very close, though.

You should definitely be very happy with your new numbers. Your Cobra must be an absolute blast on the street. :burnout:

 

[greenflash00]

Glad that 98 Saleen Cobra posted those comments because he's spot on correct. The chart that you posted would be more complete if it showed blower speed and the affect of long tube headers on boost (psi).

But for what it's worth (not comparing apples to apples, of course), on an Eaton setup a 2.8 upper vs. a 3.2 upper & 4 lb. lower produces almost the identical RPMs (17,643 vs. 17,469). I don't know the source of the chart I am referencing, so the RPM comparison may not be spot on correct. It's probably very close, though.

You should definitely be very happy with your new numbers. Your Cobra must be an absolute blast on the street. :burnout:

Thanks Bob...Yes I've had her in "kill mode" all week and the car is an absolute animal on the street. My R888s are finally struggling :lol:

To reference the chart I posted it was my understanding these pulley comparisons were done on the same car with the same mods in order to get those figures. I don't know whether or not the car tested on had longtubes but I know it was meant to be used as a guide for choosing the correct pulley combo so it would stand to reason that it would be tested back to back from VMP to get that. If I look at my graphs I can see about a .2-.5psi drop in boost from last time but I was coming from an offroad mid pipe anyway. My thought its that blower rpm should be nearly identical as well. Thanks for the great post :beer:

 

[ironreaper23]

Nice numbers!

To help this comparison, I ran the numbers for your pulley combos.

All that really matters in your case is the overall ratio between the supercharger and crank pulleys.

Setups: (lower ratio means slower speed)
3.2/4lb lower (8.6) - Overall ratio: 2.69
2.8/stock setup(7.6) - Overall ratio: 2.71

3.0/4lb lower (8.6) - Overall ratio: 2.87
2.6/stock setup(7.6) - Overall ratio: 2.92

If everything stayed the same with your setup, it would be a slight decrease in PSI since you've actually decreased the speed of the blower by about 1-2% from your previous setup. I'd say you are seeing gains from the headers since that is the only major change.

Hope this helps!

 

[Bdubbs]

With only changing headers/x pipe I went from 576 to 584. I didn't see much of a gain. That's a whopping 8 rwhp. I do think it's helped my current 19 psi and e85.

 

[BoostedByV]

wow great numbers..blows my 2.9 out the water

 

[greenflash00]

With only changing headers/x pipe I went from 576 to 584. I didn't see much of a gain. That's a whopping 8 rwhp. I do think it's helped my current 19 psi and e85.

Brady, How many degrees of timing are you on for each tune? Tuner said I'm at 18* on pump and 20* on corn. I've always wondered if your tuner might be keeping your setup extremely conservative. That is weird to me to only gain 8 peak hp coming from stock manifolds.

 

[MG0h3]

With only changing headers/x pipe I went from 576 to 584. I didn't see much of a gain. That's a whopping 8 rwhp. I do think it's helped my current 19 psi and e85.

Did it pull harder in the midrange?

Im about to do headers on my car so just curious.

Not sure if Im going to pulley down and tune or wait until I do E85.