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Hey gang, Did some speed runs against 2 Duratecs at the Plattsburgh meet and we stayed neck and neck until top of 3rd gear, where they both passed me going into 4th and pulled away. Is my SVT just plain slow or is it simply the drag from the huge rubber making the difference?? (225/40R18 Toyo T1-S) I know when I went with a plus-2 tire package on my previous 4 banger car it really killed it, does anybody else have this experience with their SVT? Or am I the proud owner of the slowest SVT ever built?  Oh, could it be that I'm still running the original plugs?? I don't think that could hurt the performance THAT much... Any ideas?
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THe only thing that would affect performance is a heavier wheel/tire combo. If yoo got light 18" wheels, there would be no difference. Also, the difference would come at low speeds, not at high. In third gear, there would be no difference. So, maybe it's time for some mods or maybe your plugs are worn.
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Well, my rim / tire combo weghs in at 40 lbs apeice. This is something like 2 lbs higher than stock SVT wheels with Goodyear rubber so I don't think the difference is there.
What I think is that the drag from the bigger contact patch of these tires is going to grow as speed rises. My highway gas mileage seems to have gone down, outlining this. The car is still very peppy off the line actually, it's past 60mph that it seems to have lost it oomph... Oh, the wider cross-section opposes more resistance to wind as speed builds too, also resisting acceleration.
I guess I was more wondering if somebody else noticed that, and maybe documented it? 1/4 mile before / after rim upgrade? G-tech times even?
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Rotational inertia is part of the culprit. 18 inch wheels have more mass farther from the centerline and this decreases acceleration. Sport Compact Car did an article that compared effects of larger wheels on a Mitsu Lancer rally car and found increased acceleration time even when wheels weighed nearly the same. It isn't the weight as much as the location of the weight.
Fastest Contour at SZ 2002 Auto-X. 10th in PAX out of 125. CEO of FOGEY(Fast Old Guys Emasculating Young-uns), Inc. Terry Haines, Chairman, Senior V.P.s: (alphabetical)JavaContour, Jet Mech, MFE, SeicoRacing, SVTSTS, Vern Kilburn. If your not a member, yet, wait a few years. I'm not just the CEO, but I'm a member, too. Working with the rank and file to get the job done right!
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63 TVR (1K in 74), 75 TR-7 (paid cash new), 79 RX-7 (zoom,zoom), 81 RX-7GSL (autobahn-driven),82 Mustang GT (autobahn-driven), 85 Mustang GT (SE Division F Stock Solo II Champ), 86 MR-2 (3rd SE Division D Stock), 88 Civic DX (had 1st born and still owned MR2) 92 Sentra SE-R (all go and no show), 98 EO SVT Contour (FTD SZ 2002). 02 Altima 3.5SE 5 spd!!!
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Makes sense. Enough for my SVT to get passed going into 4th gear by an SE whose only mod is the SVT exhaust? Or is my car an old dog?? 
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If I recall there was minor quarter mile difference between 16 and 17 inch wheels but 18 inch made a difference of several tenths in the quarter mile. They also had slower lap times despite lower profile tires.
Ford Focus has similar problems going to larger wheels. I noticed even the new Jag X-type is keeping the 16 X 6.5 wheel size to improve acceleration.
Fastest Contour at SZ 2002 Auto-X. 10th in PAX out of 125. CEO of FOGEY(Fast Old Guys Emasculating Young-uns), Inc. Terry Haines, Chairman, Senior V.P.s: (alphabetical)JavaContour, Jet Mech, MFE, SeicoRacing, SVTSTS, Vern Kilburn. If your not a member, yet, wait a few years. I'm not just the CEO, but I'm a member, too. Working with the rank and file to get the job done right!
Historical:
63 TVR (1K in 74), 75 TR-7 (paid cash new), 79 RX-7 (zoom,zoom), 81 RX-7GSL (autobahn-driven),82 Mustang GT (autobahn-driven), 85 Mustang GT (SE Division F Stock Solo II Champ), 86 MR-2 (3rd SE Division D Stock), 88 Civic DX (had 1st born and still owned MR2) 92 Sentra SE-R (all go and no show), 98 EO SVT Contour (FTD SZ 2002). 02 Altima 3.5SE 5 spd!!!
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Still, several tenths in the 1/4 shouldn't justify my SVT getting passed by a stock SE at the end of 3rd gear... She's not using up any oil, but I think my baby's sick Do new spark plugs make such a difference? Mine are original and my engine has 60,000 miles...
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Actually I just threw my stock svt rims and tires on a scale at fedex and they were 43 pounds so sounds like you 18's are even lighter. This is just a guess but I wonder if the fact that it taks longer for a full tire rotation has anything to do with it. I dont think it would but Im not sure Brian Originally posted by Silversvt:
Well, my rim / tire combo weghs in at 40 lbs apeice. This is something like 2 lbs higher than stock SVT wheels with Goodyear rubber so I don't think the difference is there.
What I think is that the drag from the bigger contact patch of these tires is going to grow as speed rises. My highway gas mileage seems to have gone down, outlining this. The car is still very peppy off the line actually, it's past 60mph that it seems to have lost it oomph... Oh, the wider cross-section opposes more resistance to wind as speed builds too, also resisting acceleration.
I guess I was more wondering if somebody else noticed that, and maybe documented it? 1/4 mile before / after rim upgrade? G-tech times even?
2000 SVT Green
KKM True Rev
Pioneer 6200 Head Unit
Rockford 800a2/600a4 amps
Infinity kappa's/Polk 12" dx128 subs
Short throw shifter/Voodoo Knob
ADR Revolution Rims
Toyo T1S 215/45/17
Bassani Cat Back
Next Mod: SHO Y PIPE/Diablo Chip
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Originally posted by Silversvt: Still, several tenths in the 1/4 shouldn't justify my SVT getting passed by a stock SE at the end of 3rd gear... She's not using up any oil, but I think my baby's sick Do new spark plugs make such a difference? Mine are original and my engine has 60,000 miles... Change those plugs! Even though they are made to last 100k miles, that does not mean you will get optimal gas mileage and performance. Buy some new double platnium plugs (NGK, Bosch +4, Autolite) and you'll notice a difference next time you hit 4000rpm. I plan to change mine at 30k miles, as I am only at 15k now. On my 99 F-150, at 40k miles, I notice it being a bit being slow. Idle is rough too. Not as noticeable in a V8, but... Plan to change them this weekend.
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Brian: Thanks for the info, saves me a trip to the shed to weigh one of those wheels. Was that the E0 or E1 wheel BTW?
Okay so plugs it is! I'm gonna go for the Bosch +4's as these seem most popular with CEGers. As a baseline I will throw the stock wheels back on and run Jeff in his Mystique again. We'll see how much of a difference the 18's really make then. Next will be plugs and a heat shield in for my intake.
Thanks for the input guys, any more ideas?
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