1997 GTS NEW 3.2L Roe Supercharger Dyno Results

[PBE97GTS]

Just had the car tuned and these are the results:

Mods:
• 3.2L KB Blower
• Boost:8.4 psi
• Magnuson bypass valve
• NGK BKR7E Spark Plugs two steps colder
• Mobil 1 0w-40
• 5.8” crank-pulley
• 2 Bar Map Sensor
• EMS: SCT Tuner w/ Forced Induction Tune
• 69lb Deka 107961 Injectors
• High Flow K&N Filters
• AEM Water/**** 1000cc/min Nozzles x2
• 400 lph Walbro fuel pump
• Snow Performance Boost Juice 50/50 ****/Water
• Smooth Tubes
• Borla Cat-Back 3”
• Low Resistance Plug Wires (qualitywires)
• Roe 2.5' Direct Replacement High Flow Cats
• 98’ Viper larger radiator fan + larger fan relay
• Deka ETX30L battery
• Torco Accelerator 32oz in 19gal = 96 equivalent octane

Max power=543 rwhp
Max Torque=566 rwtq

 

[ViperJohn]

That should be more fun now....

 

[speedracervr4]

Who tuned it?I would have expected more out of a 3.2L

 

[SquadXX]

I was thinking the same, more like low to mid 600

 

[PBE97GTS]

It was tuned by Todd over at A&C Performance. He tuned it pretty aggressively.

 

[Viper Specialty]

Something is not right.

 

[DDlesk06]

Congrats on the build... power output appears on the low side...

 

[PBE97GTS]

Something is not right.

What do you think is wrong?

 

[steve e]

Look in to that, you should be making way more power with that blower, with just heads and bolt ons they dyno higher.

 

[EllowViper]

Yeah...you are going to get a lot of head scratching on your dyno results. Todd would be the best to critique his work...not any of us. BUT you posted it so here we go.
1. Plugs too cold. Only need one step colder at that boost since you are running W/M.
2. 8.4 PSI with the 3.2 blower tells me you are not stressing the blower and IATs should be much better than the same PSI with the smaller blower. This is basically the benefit of the 3.2 Less parasitic drag to develop the same boost. All good; especially with W/M.
3. Timing. Need to see the timing spread...since you are tuning with TORCO. Should be able to run a lot of timing with W/M and TORCO. Timing alone will [should] net you into the 600 RWHP range given what you've posted.
4: W/M....might be injecting too much (1000 x 2) seems a bit excessive. Could be quenching your entire combustion process. When I was at 16 PSI boost, I ran 1400 ml total on a progressive cooling mist controller and the engine just screamed (oh...on a one step colder plug too).

So personally, check the amount of W/M, timing, and plugs/gap. Everything else seems well matched.

 

[speedracervr4]

My 8# set up(2.4L ****/VEC and high flow cats) got me 606hp/660tq. I would not consider Quality wires a low resistance wire.After measuring them I switched back to MSDs.

 

[PBE97GTS]

Yeah...you are going to get a lot of head scratching on your dyno results. Todd would be the best to critique his work...not any of us. BUT you posted it so here we go.
1. Plugs too cold. Only need one step colder at that boost since you are running W/M.
2. 8.4 PSI with the 3.2 blower tells me you are not stressing the blower and IATs should be much better than the same PSI with the smaller blower. This is basically the benefit of the 3.2 Less parasitic drag to develop the same boost. All good; especially with W/M.
3. Timing. Need to see the timing spread...since you are tuning with TORCO. Should be able to run a lot of timing with W/M and TORCO. Timing alone will [should] net you into the 600 RWHP range given what you've posted.
4: W/M....might be injecting too much (1000 x 2) seems a bit excessive. Could be quenching your entire combustion process. When I was at 16 PSI boost, I ran 1400 ml total on a progressive cooling mist controller and the engine just screamed (oh...on a one step colder plug too).

So personally, check the amount of W/M, timing, and plugs/gap. Everything else seems well matched.

I had one step colder plugs in the car and Todd suggested 2 steps colder.
AEM does suggest the 1000 for my hp range but maybe that is just for 1 nozzle (500x2).
A/F ratio was a solid 11.7
Plug gap is set at .035

 

[EllowViper]

Definately investigate the W/M nozzle sizing. Many start with 325 x 2 and tune from that baseline. A/F can be a bit leaner given the benefits of W/M. I ran 12.0-12.5 @16 PSI on a safe tune only because of the W/M effect. No W/M, stay in the 11.X range. I was able to go to about 20 degrees timing at 6000 RPM; depending on IATs. You will easily be able to hold that much timing @ 8 PSI with W/M and TORCO. I was able to run a .035 gap @16 PSI as well but used the Demon coils. Not sure if you are able to use that gap given the W/M amount you are running. Reduce the W/M and that gap should be OK. I'd still run a one-step colder plug simply due to driveability when not into the boost...especially gven the inherant design of the ROE manifold.

 

[plumcrazy]

id be pissed if i did all that work and spent all that money for those results. and todd is one of the best, what does he think ?

 

[PBE97GTS]

id be pissed if i did all that work and spent all that money for those results. and todd is one of the best, what does he think ?

He didn't say much, just that I should be making more power and I should be using 100% **** or 70/30.

 

[speedracervr4]

Not sure I would run 100% ****. 50/50 helps with the intake cooling factor as is needed with the Roe with no intercooler and it also keeps the flammability down. Plenty of guys make decent power with 50/50. Hell some run 5# with no **** and get the same results as you. Coincidentally I was running your same wire/plug combo after doing my heads/cam /2.8L upgrade a few years ago and Sean Roe was having issues getting power while tuning it. Greg Good had mention pretty much the same thing Ellow in regards to plug selection and he had also said check wire connections. We decided to go back to the Bosch plugs and MSD wires and the car picked up the power we were missing.

I assume you got the new kit with the improved lower intake. did you port it at all? I wonder if it's more restrictive than the old design.

 

[PBE97GTS]

Yea, it's the new intake manifold with no porting. Even Scott at Roe is making typical power from the new design 600+. I will slowly explore all ideas and try to pinpoint the problem.

 

[EllowViper]

I've never understood the enamoration with the "100% methanol" discussion. Notwithstanding the volitility issue, the only reason you do a W/M system is to manage IATs and better control the combustion process. Methanol does very little in that regard. 100% water is actually much better at managing IAT and combuston/detonation. Do the research on latet heat of evaporation. If you use 100% ****, you have to view it as additional fuel...not as anything else. And then the issue of tuning for that additional fuel is very complicated. Your IATs may be a bit lower (not lower than it would be with water), but your combustion temps will be through the roof! THat in an of itself is counter-productive to your goals. "But Ellow...its a high octane fuel and I need the octane boost"...Wrong again. Yes its high octane in and of itself, but the amount you are delivering via your methanol injection is only 10-15% of the fuel volume your engine is using. Doing the math, that only equates to MAYBE a 1 octane point increase over your pump gas in the tank. Absolutely the wrong way to "raise your octane" in the engine. Agan, 100% water is a more effective way to manage combustion temps, timing advance, and in effect, your desire for more octane. Also, water doesn't burn...so when that highly saturated water vapor in your combustion chamber is 'flash vaporized' during combustion, it expands to 800% its volume (steam engine effect), absorbs a lot of combustion temps in the process, and saves your engine from all sorts of bad combustion. Thus the ability to run leaner (12.x AFR) at much cooler EGTs and a one step colder plug. 100% methanol will require AFRs in the low 11.x range (its a fuel) and becasue methanol is a fuel and it burns, EGTs will be elevated beyond normal and you will indeed need a much colder plug. Just my $.02.

 

[PBE97GTS]

UPDATE:

I changed the plugs to 1 step colder, reduced my methanol nozzles to 500cc x2, added Harland Sharp RR, M&M headers, removed the cats, and did a compression test.
I went back for a retune and ended up with the same hp/tq numbers. Next step is to do a leak down test and check for boost leaks. It seems that I am only making 5lb
of boost all the way up to about 5000 rpm then a spike to 10lb. I am supposed to have an 8lb pulley but I guess I am in uncharted waters by using the supplied Roe smaller crank pulley.
I am thinking that the supercharger is simply not spinning fast enough to make 8lb. Even so I should have picked up much more power with my recently added mods but stayed the same.
This situation is very odd and troubling since most potential issues have been ruled out. Any other ideas on what to look for would be great. Thanks.

 

[EllowViper]

"Roe smaller crank pulley..." WHat is that? You don't want a smaller crank pulley but a larger one (Weaver "over drive" pulley is larger) unless the new system has a really small blower pulley to offest the smaller crank pulley....but why if thatis the case???. A smaller crank pulley (underdrive pulley) spins things slower. Its exactly OPPOSITE of what you need. You want a smaller snout drive on the blower and a larger crank pulley to get things really spinning. Stay with the stock pulley and you will get the boost you want. I'm thinking Sean is slowing down things with the 3.2 blower vs. what the blower was spinning with the 2.4/2.8. You need to calculate the airflow a 3.2 blower will develop at 6000 rpms and then what the engine needs from a VE perspective at 6000 RPM at 8 psi of pressure differential (well in reality, 1.5 atmospheres (14.7 standard pressure plus and additional ~1/2 atmosphere (~8 PSI of boost). There are calulators out there to do that. I think you can call Kenne Bell with all this and they will calculate the crank and blower pulley sizes needed to get 8 psi on a 8.0 ltr engine at 6000 RPM with the 3.2 blower.

 

[PBE97GTS]

Another Update (Problem Solved?):

I just ran the Leak Down test at 80psi and here are the results:

1. 4%
2. 5%
3. 5%
4. 4%
5. 4%
6. 4%
7. 4%
8. 5%
9. 3%
10. 3%

So after that I decided to hook up a fuel pressure gauge to the fuel rail to perform a fuel leak test.
Once the key was turned and the pump primed, I was only reading around 15 psi. I believe this should be around 55 psi.
I didn't notice any fuel leaks so I pulled the vent tube off the top of the fuel pump hanger and turned the key on.
I noticed that fuel was spraying back into the tank. I used the hose that came in the Walbro fuel pump kit and it fits well around the pump barb but not so much around the regulator barb.
I believe that the car was simply maxed out on fuel which would explain the hp/tq cap even with added mods since the 1st tune. At 15psi the pump would be running at around 200lph rather than its rated 400lph.

Next step is to use a tighter fitting hose around the fuel regulator barb and a reducer to the fuel pump.
Oh and I will be putting the stock crank pulley back on which should get me to 12-13 psi.

 

[PBE97GTS]

So I realized yesterday that the fuel being released back into the tank is just the regulator dumping excess pressure.
The fuel pressure does sit at 55psi when the car is running but only holds 15psi when primed and not running. I guess that is just what this particular regulator design does.

Does anyone know if this is the typical behavior of the stock FPR?
I have seen most other cars hold operating pressure when primed.

So I then secured the line and took the car for a drive. I am still only getting 5psi on an 8psi pulley. However, the SC pulley has an OD of 2.95" which is quite large.
That combined with the small crank pulley could be why I'm not seeing my desired boost.

 

[Free2go]

That combined with the small crank pulley could be why I'm not seeing my desired boost.

Yeah, that's pretty much what Ellow said.....2 days ago.

 

[PBE97GTS]

"Roe smaller crank pulley..." WHat is that? You don't want a smaller crank pulley but a larger one (Weaver "over drive" pulley is larger) unless the new system has a really small blower pulley to offest the smaller crank pulley....but why if thatis the case???. A smaller crank pulley (underdrive pulley) spins things slower. Its exactly OPPOSITE of what you need. You want a smaller snout drive on the blower and a larger crank pulley to get things really spinning. Stay with the stock pulley and you will get the boost you want. I'm thinking Sean is slowing down things with the 3.2 blower vs. what the blower was spinning with the 2.4/2.8. You need to calculate the airflow a 3.2 blower will develop at 6000 rpms and then what the engine needs from a VE perspective at 6000 RPM at 8 psi of pressure differential (well in reality, 1.5 atmospheres (14.7 standard pressure plus and additional ~1/2 atmosphere (~8 PSI of boost). There are calulators out there to do that. I think you can call Kenne Bell with all this and they will calculate the crank and blower pulley sizes needed to get 8 psi on a 8.0 ltr engine at 6000 RPM with the 3.2 blower.

UPDATE:

So this was the issue. The underdrive pulley was the culprit. The smaller crank pulley that came with this new kit has an OD of 5.8" and was combined with a snout pulley of 2.95" which on the old kit=5lb. Kenne Bell estimates +3psi with the larger 3.2 blower on the same pulley size.
The OE crank pulley has an OD of 7.2". Scott at Roe was nice enough to send me another belt so I could put back on my stock crank pulley. After the install I went for a little test drive and noticed right away that the car had much more power.
The boost response was instant and it was hitting a max of around 12psi. It does seem that the difference in boost is huge! I am happy with 12psi but I'm not sure how someone can run anything very specific in-between.
I realize that different mods = different boost but a 7psi jump? Well now with 12psi I won't have the itch later to increase the boost. On a side note my tensioner is strong and there is no belt slip.

Old Kit Pulley Size/Boost:
2.95 is the 5lb
2.8 is the 6.5lb
2.65 is the 8lb
2.5 is the 10lb

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[rschiltz]

Glad you got it figured out, will be curious what your new numbers are.

 

[plumcrazy]

Well now with 12psi I won't have the itch later to increase the boost.

quoted for future reference...

and id get it tuned again ASAP unless todd says differently

 

[Bobpantax]

Do what Plum suggested. I had an 8 pound Roe system on my former 1999 GTS. The calibration is crucial. You do not want to be running too lean. Do you know your current A/F ratio after the corrective changes?

 

[Bobpantax]

Do what Plum suggested. I had an 8 pound Roe system on my former 1999 GTS. The calibration is crucial. You do not want to be running too lean. Do you know your current A/F ratio after the corrective changes? I suggest you get a new dyno run and post the graph. Make sure that you state the type of dyno used. Mustang dynos read 10% lower. I see the dyno above was done on a dynojet.

 

[Free2go]

Do what Plum suggested. I had an 8 pound Roe system on my former 1999 GTS. The calibration is crucial. You do not want to be running too lean. Do you know your current A/F ratio after the corrective changes? I suggest you get a new dyno run and post the graph. Make sure that you state the type of dyno used. Mustang dynos read 10% lower. I see the dyno above was done on a dynojet.

Forgive me if I stray off topic for a sec, but Bob, did you order a black on black Demon? Seems like that car was made for you.

 

[Bobpantax]

I will PM you since I do not want to divert the subject.