To supercharge or not that is the question

[drewfusion]

I got a 2007 Shelby GT about a month and a half ago and it's my everyday driver. I want to supercharge it but I don't want to shorten the life of the engine which I've been told by guy's at Quantam and Shelby it won't as long as I keep it under 500hp. I was also worried about having to replace the clutch to just because I couldn't see how it would hold up to all that hp when I did decide to put my foot in it. A guy I talked to at Quantam said my clutch would be fine but yet reading some of the posts in the forums I here otherwise. The Paxton/Whipple debate is endless although both people I talked to at Quantam and Shelby like the Whipple cause it's power right when you step on the gas. I just want the supercharger that gives me the best 1/4 mile time and that might be the Whipple depending on if you think it's better to start strong out of the gate or Paxton if you think gears are what get you strong of the line and a supercharger that engages around 2500rpm and on makes you finish strong. Since the Paxton has to be reved up to higher rpm's to really engage it makes me think it might be the better choice just because when your driving around town it's like it's not there so therefore the motor can operate like it would if you didn't have a SCTo supercharge or not that is the question thus giving the impression that your ensuring longevity for the motor, whereas with the Whipple it's going as soon as you get on the gas giving the impression it might be alittle harder on the engine over time than the Paxton. I don't like that with the Paxton they have to tap into my oil pan, seems like this would eventually leave oil drips in the driveway of coure it gets fresh oil every 3000 miles which with the Whipple you can go 50,000 miles before you have to have it changed according to Quantam. Somebody PLEASE HELP ME MAKE UP MY MIND!!!!!!!!

[ShelbyGT/SC]

Drew I am pretty sure I read/heard they don't need to dill into the oil pan any longer for the Paxton.

If this helps, Tasca swears by the Whipple too.

Since I have a Whipple I must say it is incredible and you should go for it. However you mentioned your concern of engine life. I am wondering how many SGTs are out there with a supercharger that are daily drivers. I suppose a 500 hp daily driver is becoming more common these days but perhaps not with a 4.6L AL block without forged internals. I don't know the answer but I too would have the same concern. I am sure there are experts out there who would say it is okay.

If you are comfortable with that then I recommend the Whipple.

[drewfusion]

Thanks Adam. I'm assuming yours is not a daily driver?? It's hard to tell if when your talking to someone at Quantam or Shelby and there telling you it's not that big of deal and I shouldn't worry about hurting the engine or shorting the life of it, if it's because it's their buisness to say it's not really a problem I mean they are in the buisness of modding these cars if they detered very many people from doing a $8,000 mod they wouldn't be in buisness very long, by the way your car is gorgeous, what size razors are you running??

[stump_breaker]

SGT=peanut butter

S/C=Jelly

 

The only reason I don't have a Whipple yet is because we have decided to wait until the warranty is out before modifying the engine. The guys at QP are awesome and I would take what they say to the bank.

 

Glen will be getting my car in a couple of years for the Whipple install.

 

I saw Josh in Mesquite and he came over and introduced his family to me. Great guy!

 

I told my wife if it wasn't so far away I would go see if I could get on at QP somehow even if it was just to wash the cars!

[ShelbyGT/SC]

Drew it's a fine line as they are they experts too. Lots of us went through all the same thoughts and discussions last year. At first all I was going to do was just have Tasca take my car to around 450 naturally with a more rugged and smooth inlet elbow, pulleys, tune and other but then I was offered the first Whipple in 07 so it was a no brainer.

Thanks for the compliment and my Razors are 20 inch.

[clark17357]

And, then, along came the SAI Kenne Bell option for our SGTs.

 

When Adam said he did not think one needed to tap the oil pan with the Paxton, that is correct for the newer units that are being sold now. If you opt for the Paxton (which it does not sound like you will), make sure you ask if they are installing the newest model.

 

In terms of shortening the engine life, you will fine no reliable data on that subject from the view of a daily driver. The overview posted already is as accurate as can be had with the present knowledge base.

 

Good luck with your decision.

 

Jim

[68fastback]

I'll try to address some of your questions as best as I can.

 

First off I have to say that *any* modification that adds power will shorten engine life to the extent you use the power. There are no true 'thresholds' ...all shades of grey. Of course, the engine can also fail (vs shortened-life), but that's less likely at 450crank HP and under with either type product, a quality tune, prudent use and regular maintanance (good idea, imo, to switch to a quality full-synthetic oil and only use OEM or FRP-racing filter too).

 

The Paxton/Vortech/ProChargers are centrifugal S/Cs so power builds most effectively with higher rpm since boost is created with an air-turbine/impeller such that each rotation produces less boost at lower rpm than it does at higer rpm.

 

The Whipple/Eaton-TVS/KB are fixed displacement pumps that produce nearly identical flow with every rotation regardless of rpm, so boost comes on earlier than the centrifugals.

 

If both types were to produce identical peak results (pick a number), there will *always* be more area under the torque curve with a fixed displacement S/C. That's a significant difference. As a result, if you can get the power to the ground (and still assuming the same peak HP in both cases), the fixed-displacemnt designs will have more potential for quicker quarter miles.

 

So why would anyone want a centrifugal? Since the ppwer comes on higher in the rpm range, it will stress the motor less in low-mid range (less torque) and this may be a longevity advantage because it will reduce low-mid range block and cylinder distortion -- all engines flex a bit with power and the closer you get to the engines design limits the more problematic this flex becomes in terms of wear and possible component fatigue/failure.

 

You can see there's no easy answer -- more power always gets you closer to the 'limits' ...whatever they are ..and closer to the limits affects longevity -- even if just bearing/ring/cylinder wear, etc ...more force, more friction, more wear per unit of time at higher forces.

 

Another question you eluded to is a possible benefit of the centrifugals in street use. You reasoned that since they come-on later in the rpm band it would not engage in street use, more like it's not there. While that's somewhat true, it's also true that the fixed displacement S/Cs are managed such that they only give you that low-mid boost if your right foot asks for it. When driving such that boost is not needed (naturally aspirated output is sufficient to satisfy your right foot), no boost is actually provided. So, to that extent, they both are very tractable in street/highway/commuting use but the fixed-dsiplacement type gives you the option to use boost (or not) in the low-mid range where the centrigfugal is not yet offering as much assist (again, at your right foot's request).

 

That said, my bias is for the fixed displacement S/Cs because their strong mid-range torque permits more relaxed street driving. If you don't use the enhanced low-mid torque they offer, your milage will be evry bit as good as a centrifugal and both will be only marginally different than stock (of course you will use it sometimes ;-)).

 

While I don't think tapping the oil pan is a big deal, the new Paxton/Vortech's and the ProCharger don't require that. Still some prefer the s/c gear-train cooling benefit that the old pan-tap design may offer, while it bothers others to mod the pan -- it's a personal call, I think.

 

While both designs are quite durable/reliable and have excellent driveability, the attraction of the fixed-displacement designs, imo, is simply the bigger kick in the butt they offer over a broader rpm range, but (peak-for-peak comparison) that additional low-mid range will stress the motor a bit more if you use it. So, in a way, you could say the fixed-dsiplacement designs offer the driver more power-use options -- when to shift on a road course, and requiring less downshifting for passing (low-mid torque) on the highway, etc.

 

If you keep it relatively conservative (under 450 or 500crank) that should not be a problem (failure) but all power adders will reduce engine life depending on how much they add and how often your right foot asks for what's available. If you start pushing toward 500rear-wheelHP and above, you're much more in the danger zone with the alloy 3V, imo. Still, there are many modded in that range and much beyond but they surely will not see as much long-term life and will be more prone to short-term failure.

 

Hope this helps a bit ...can't be more precise because it's all shades of grey and ultimately comes down to what you're looking for based on how you plan to use the car, etc. The good news is that these are all well-engineered products, imo, with quality packaged tunes (tho a custom tune can get you more ...if you dare) -- not a bad choice in the lot, imo.

 

Just some things to think on... -Dan

[LuLu]

Don't kid yourself, every power adder increases wear and tear. Be it supercharging, turbocharging, NOS, or even a simple canned tune on a N/A engine, you are trading away longevity. How much is a matter of how conservative the application, and how much you hammer the power.

 

IMHO, the differences between "fixed displacement" blower and a centrifugal are grossly exaggerated, especially on the 4.6L-3V. Though it's shortcoming is that it's basically a "square" design naturally short on low end torque, this engine breathes like no other engine I have seen over my years. Awesome lungs. Thus, if you are seeking a wise decision, you have to ask several related questions.

 

How much boost at the top end? "Fixed displacement" means fixed output throughout the RPM spectrum. A centrifugal blower is limited only by your red line. (6250 RPMs on a stock 4.6L-xV short block). The answer is in the second 1/8 mile numbers. A centrifugal will outperform a "fixed displacement" blower every time. At least this has been my experience. Moreover, the winning pros at the drag strip employ centrifugals, turbos and twin turbos. What does this tell you?

 

Heat soak...How much heat is generated and transferred to the engine? All blowers generate heat, when you compress air, it gets hot. "Fixed displacement" blowers generate more heat than centrifugals and they sit inside the engine valley, and usually on top of the intercooler. Run it hard enough, or long enough, and you get heat soaked. Centrifugals are outside the engine and though they also generate heat as well, it's heat not transferred to engine internals.

 

Intercooling...Don't leave home without it. But, where is the intercooling taking place? If it's inside the engine valley underneath a blower, the size and capicity of the intercooler is likewise "fixed" and can be overwhelmed and inefficient under some circumstances. Not the case with centrifugals, the intercooler is also outside the engine, and it's capacity is limited only by engine bay space.

 

Tapping the oil pan...Again, grossly misunderstood. It's a drain away from the blower head, not a supply line. Thinking in terms of longevity again, I'd rather have a blower head lubricated by clean, cooler engine oil, than a fixed lubrication supply that is as hot as it surroundings and has to be changed every 10K or so. It's a small hole in the pan, and when done right, no leaks. Been here, did this too.

 

I could go on, but I won't. My point is that the differences between the styles of supercharging are very minor and greatly exaggerated. Again, the proof is in the time slip numbers. I've seen 60' times in the 1.60s on from a 4500 pound car with a 4.6L-4V and a Vortech V2 T trim, and it walked away from "fixed displacement" powered cars every time. The MPH gain in the second 1/8 mile is impressive.

 

Just my .02C, happy motoring gents.

[GT500-07]

Dan,Mac you two should write a book, great information, Thank you. On to Turbo's

[moabman]

Hey - we agree GT500-07!

 

One thing that needs to be emphasized when talking about the potential wear and tear is a lot depends on how you drive! Most of these kits have a by-pass that keeps the parasitic drag to a minimum. A slight drag still remains and LuLu is right it, will cause a minute amount of wear to the engine. However, the blowers will allow you to add more significant stress to the engine if you choose to. Remember, that blasting away at every stoplight with the NA engine will also add stress and shorten its life. It's up to you.

 

I went the supercharger route because I like to have the option to open it up when I feel like it. I love having that option. If I did drive it daily it would be extremely easy to stay out of the boost and get my 100K + out of the fabulous Ford 4.6.....

 

Remember, you will still be in control even with a blower.

[drewfusion]

Thanks so much for all the great info and feedback!! I was ready to go Whipple until LuLu posted. It would be interesting to have some Paxton time slips compared to Whipple on an '07 SGT although the driver does make a difference. I thought the car stock was a high 13 car stock. I figured the S/C would get in the low 12's until I read the post where he said with his "poor driving skills" he got a mid 13. I haven't ran mine at the track just yet I'm wondering with a good run if it will run a high 13??

[LuLu]

Thanks so much for all the great info and feedback!! I was ready to go Whipple until LuLu posted. It would be interesting to have some Paxton time slips compared to Whipple on an '07 SGT although the driver does make a difference. I thought the car stock was a high 13 car stock. I figured the S/C would get in the low 12's until I read the post where he said with his "poor driving skills" he got a mid 13. I haven't ran mine at the track just yet I'm wondering with a good run if it will run a high 13??

The stock (out of the box) SGT is a mid 13.xx car in the 1/4 mile. Any blower (your choice) should put you into the mid 12s with a safe tune. Likewise a conservative application of nitrous. If not, it's the driver.

 

On the car I described ^ there (a supercharged Marauder), I ran 11.80s with 106 octane and the appropriate tune on a built engine. On my stock engine with 93 octane (again, with the appropriate tune), 12.5x all day long with 9.5 PSI of centrifugal boost and water-to-air intercooling, until the bottom end gave up.

 

But, please don't let this deter you, the -4V 4.6L aluminum engines in the Marauders had a head cooling problem not present on the -3V engines, and the 4R70W auto tranny needed a lot of help as well. #8 hole ran 20 degrees hotter than the other 7, and it was last on the fuel/food chain as well.

 

Still...IMHO, 10 PSI of boost (from any resource) is the "hard deck" for stock 4.6L-?V engines, and even then and just with ocassionnal boost and timid driving, you will be rebuilding something somewhere in the 50K mile range.

 

With stock engines in play, and regardless of the style of super/turbocharging, your choice of 5, 6, 7, and 8 PSI of boost may provide you with 100K miles of true driving joy. However, inch over 8 PSI, and the wear and tear on the stock engine will keep you out of "beer heaven", and Julia Childs will come out of her grave to bang on your door to ask "what the Hell are you mixing, you fool?"

 

The SGT is a very fun car to drive in it's natural stock state. Adding some ponies with an aftermarket power adder is also fun. But, like Clint Eastwood said in one of his "Dirty Harry" films, "a man has to know his limitations". It's only a 4.6L, gents, 281 CID hauling a 3400 pound chassis. 500+ RWHP is not only silly, it's destructive. As it has been said here before, you just pulled the pin on a hand greneade. How long can you hold it?

 

Let's meet back here in say...one year...And let's talk about who replaced, or, rebuilt their short block?

 

And, let's try to be honest about that?

[JeffIsHereToo]

I'm convinced that SAI will offer a package, like the SS package for the GT500, for our cars in a year or so and I've decided to wait and see what that looks like before I make any major changes.

 

Anyone else think that's the case or am I dreaming?

[clark17357]

I'm convinced that SAI will offer a package, like the SS package for the GT500, for our cars in a year or so and I've decided to wait and see what that looks like before I make any major changes.

 

Anyone else think that's the case or am I dreaming?

Hi Jeff,

I doubt we will see that. The numbers are just not there for SAI to produce a package that will be so expensive by definition. I see the SGT as the true reincarnation of the GT350 in terms of the purpose for which it was engineered and built. As Lulu has pointed out, it is one fantastic road course car in stock trim. I just think people, right or wrong, will not spend SS money on a SGT, particularly now that SAI is offering the Kenne Bell S/C option. Having said that, I hope you are right and I am wrong. It would be a sweet thing to have as an option.

Jim

[RogerS]

I think you may be right in your assumption Jim. Maybe a componant package with various options to choose.

But an SS option, in my opinion, will not happen. But stranger things have happened.

 

Roger

[mach 1 1970]

I read some time ago when Ford was testing the 03 Cobra they had to use the iron block with beefed up internals. They said and( remember they really beat the ever living sh-t out of these cars when they test them) the aluminum block blew @ a alarming rate.That has allways been in the back of my mind. I know the FORD GT has a aluminum block but it's not the same casting . It was costly to make thats why the GT500 is iron.

[68fastback]

Just thinking-out-loud.... since the BOSS seems virtually assured as a Ford-only '10MY offering and is the ideal special-build base for a Shelby GT350 offering (tho likely a bit later for business reasons), I can see SAI doing a special package for post-retail '10MY mustangs for those that a GT350 might pose a big price-hurdle. Many of those [non-body] pieces might also fit and benefit the current S-GTs but I would think SAI's business model would be more disposed to offer a subset of GT350 pieces as a '10MY S-GT to provide a lower-entry and compliment a GT350 offering at some point.

 

As cool as it would be, I think it's getting a bit late for a major post-retail offering on the current S-GTs given the other options on SAI's plate and the fact there are still quite a few sSGTs still unsold/untitled and given that the '10MY 'stang early-J1 is likely only six months or so away, tho the BOSS would be later and the GT350 likely after that. Also, a '10MY GT500 SS offers SAI continued opportunites in a strong post-retail demopgraphic, imo, as well as continued revenue from the likely '10MY KR builds.

 

Still, with the three mod shops online and a couple more likely, using existing (and soon-to-be N-minus-1) FRP/aftermarket pieces on a post-retail pre-'10MY SGT package could make sense if there's enough demand and if the mod shops have excess capacity. Likely?

 

I think that an SS-priced/type package on the pre-'10MY SGTs isn't a great option for SAI at this point, but who knows? If enough customers demand it most anything is possible.

 

 

Curious, then, what are your thoughts? What mods do folks feel would make a popular post-retail package for the current (and/or future) S-GT? A full SGT-SS? Mostly performance: superchargers (the TVS would be outstanding if someone makes a lower intake/IC for the 3V), handling? Tasteful body/aero pieces (I like the SS/40th CF splitter, given getting the KR's is slim)? What would be the price-point boundaries you feel are realistic?

 

Thoughts?

 

-Dan

[RogerS]

Dan,

 

I really think that price point would be an issue. Though various price point packages could be viable.

 

The SC option and suspension upgrade ie: watts link along with a brake and wheel package would be optimal. Then you have the gauge pkg. Maybe all in a price pkg.

 

Aero bits? Maybe carbon fiber rockers and mirror covers. Not much you can really do with the CS front facia. GT500 rear spoiler?

 

You also hit on a great point on the timeliness of the post production packages. And I am in ageement with your assessment on the MY10 observations.

 

10 could be a very lucky number for the "throwback" era.

 

Roger

[68fastback]

Roger, I agree ...

 

I've heard that CTM is tweaking their Ford-Arning-designed T5 IRS (based on the original IRS Ford planned for mustang in '64) for 600HP for some upcoming Super Saleen mustang. Since Duane Carling redeveloped and sells the T5 today and I've heard is looking into that for Saleen, would that be something you think might have SGT/package appeal?

 

I'm not aware of any talk on that but it is a slick design and the granddaddy of '4-wheel-steering' IRS designs that others (like Mercedes) have licensed over the years.

[GT500-07]

Dan,

 

I really think that price point would be an issue. Though various price point packages could be viable.

 

The SC option and suspension upgrade ie: watts link along with a brake and wheel package would be optimal. Then you have the gauge pkg. Maybe all in a price pkg.

 

Aero bits? Maybe carbon fiber rockers and mirror covers. Not much you can really do with the CS front facia. GT500 rear spoiler?

 

You also hit on a great point on the timeliness of the post production packages. And I am in ageement with your assessment on the MY10 observations.

 

10 could be a very lucky number for the "throwback" era.

 

Roger

 

45th Anniversary GT350(Ford/SVT) Shelby R upfit package

[RogerS]

Roger, I agree ...

 

I've heard that CTM is tweaking their Ford-Arning-designed T5 IRS (based on the original IRS Ford planned for mustang in '64) for 600HP for some upcoming Super Saleen mustang. Since Duane Carling redeveloped and sells the T5 today and I've heard is looking into that for Saleen, would that be something you think might have SGT/package appeal?

 

I'm not aware of any talk on that but it is a slick design and the granddaddy of '4-wheel-steering' IRS designs that others (like Mercedes) have licensed over the years.

 

I have seen the T5 pkg. very impressive piece of work and to adapt to an original design would be very cool. The HP capibilites would be key in opening doors to may applications in a product or race line. Same with the Boss application going back to the Trans Am days. It was one of the many hay days for Ford in the racing community. Win on Sunday, sell on Monday.

 

Roger

[RogerS]

45th Anniversary GT350(Ford/SVT) Shelby R upfit package

 

 

Paul,

 

That prospect would be icing on the cake.

 

Roger

[68fastback]

Paul,

 

That prospect would be icing on the cake.

 

Roger

 

+1 ...good toughts Roger and Paul.

 

...from a business/brand-strategy viewpoint a 350R seems very compelling ...even the timing is potentially consistent with a TransAm redux. :happy feet:

 

Six months ago I was thinking that the key ingredient was knowing whether a TransAm series would be 5.0, 5.8 or 6.2-based as a key to what ford would do for the BOSS. Since Ford has effectively pulled the big H/B V8 off the table, that seems to say either the TransAm will be limited to 5.0 *or* Ford gets to have forced induction while GM/DCX get to play with their 6.2s (or Mark fields was being coy with us and the alloy 6.2 is further along than we know ). I don't think GM and DCX will play with Ford in a 5.0 sandbox, so a mixed displacement with power adders might be more likely -- though I cannot figure how that could be effectively policed. I'm still stuck on that one.

 

Going with the 5.0-adder assumption for a moment, that plays to a factory GTDI BOSS and a Shelby GT350R variant as 'track-mates' with friendlier-priced popular GT and S-GT versions picking up the spread when/if the 5.0 na or 3.5V6 GTDI replaces the 4.6 3V. Win with the racers and sell plenty of CAFE-tolerant streeters with FRP and SAI filling the aftermarket gap with parts and and upfit packages as in the past.

 

There's also a hot (and likely true) rumor that Ford will be reintroducing the hi-deck '351' BOSS crate motor and variants (to complement the low-deck based '302' BOSS crates intro'd in Nov 2006 at SEMA). While those are not smog/street compliant in current mustangs and would likely be for race/sport and new old-builds (falls under vintage smog rules in many states now), they certainly could serve in a 5.8/6.2 road race series as well. Given that CarCarft is presently using an aftermarket block version of that to build the 408 motor for the '67 Terlingua 'street-racer' an FRP pushrod BOSS would play well with GM/DCX, especially if FRT engineers packages for all the EFI and computer pieces needed for a cohesive turn-key package (nice for the Ford street-rod and vintage crowd too). That could be the basis of a new old-build (pushrod) TransAm series vs a modern-build factory series too -- or both together in the same series!! I think both would be popular with fans.

 

I just checked the thread topic ...I'm a bit off center on some above <lol> ...but if GTDI (TT/Twin-Force/EcoBoost) is the future for next 5 years or so (i.e. 2012 CAFE notch-up +) ...as Ford says it is, maybe we get to find out if that applies to the modular when the BOSS arrives? I have heard from more than one source that *if* a GTDI 5.0 modular ships for '10MY, mustang will get it. Then a BOSS, BOSS-racer, S-GT and GT350R make even more production sense, imo.

 

Admittedly there's only so much that can be 'divined' without more info, but I never underestimate the power of smart folks to collectively have insights that no one person can noodle, so I'm always interested in others thoughts. ;-)

[Torrence]

I had my WHIPPLE on before my first oil change.... lol...

[HIGHFLIGHT]

The Whipple 2.3L finally showed up. It is still in floor where the d;aaa FEDEX left it. The brace is still a problem for me. The solution to fix this is to order the 3.4L Whipple engine drop kit from LETHAL minus the lowering springs. The K-brace spacer is a drop of 3/4" and the modified engine mount drops additional 1/2". You will need a sway bar lowering piece also. That cost is greater than the 10% restock charge for the Whipple. Live and learn.

 

I also ordered from SHELBY the KB 2.6L SC on Thursday...they just called and said it is shipping today UPS. No problem with the brace here. Not bad from 3-4 weeks to 2 days.

 

Oh one other thing. I bought the SHELBY gauge pod without holes and ordered the COBALT A/F wideband, oil pressure, and vac/boost. ALL are 2 1/16" gages. The A/F is worth the extra cost as it takes seconds to melt a piston...

 

I got one new in the box 2.3L Whipple

[RogerS]

Awesome. You will be happy with the KB. Congratulations. Like your gauge choice. On the strut brace are you going to go with the Ford Racing V6 brace? Or did you have another in mind?

 

Now let's help you sell that Whipple!

[ShelbyGT/SC]

Now if only I could figure out a way to get that Whipple into AJ's little battery operated Tasca Shelby Jr...

[clark17357]

On the strut brace are you going to go with the Ford Racing V6 brace? Or did you have another in mind?

 

I am going to suggest the unthinkable but what I have noticed in staring at my KB now for 6 days is that the engine bay looks just fine without a strut brace.

 

Jim

[RogerS]

:o