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View Full Version : How much overdrive should I run??



smith181992
01-18-2013, 10:59 PM
Hey guys, this is my first technical thread, so bare with me please. I am finishing up a motor build for my 90 sc 5 speed and I am wondering what would anyone's recommendation be on how much over drive would be good for my car. Here are my modifications:

.30 over Wiseco pistons with 94 rods
stock crank
custom grind cam, springs, and pushrods from DD
home port and polished heads
5 angle valve job
75MM tb
port matched intake to 75MM tb
76MM MAF
42 pound injectors
255lph walbro fuel pump
chip from DD
gasket set and arp head studs from DD
3" cai
front mount intercooler w/2.75" piping
ported exhaust manifolds
full 2.5 catless exhaust w/megan racing mufflers
Sniper wet nitrous system (not sure on what shot yet, or if I'm even going to spray it or not)

Stock blower for now with 5% pulley and some port work, I don't have the money right now for a better blower, so for now, I'll have to run this blower. I was thinking maybe a 10% jackshaft pulley with my 5% sc pulley? I'd love to hear some opinions from some guys that have the similar set up! any input on what else I should or anything would be great, thanks in advance!

MadMikeyL
01-18-2013, 11:14 PM
With a stock blower, there is definitely no need to run more than 10%, and there may not be any benefit running more than 5%. I would say put it back together with the 5% pulley, and see how it runs, then if you want to try more OD, get the 10% jackshaft pulley and put the stock blower pulley back on, and see which one performs better.

bye-bye-birdy
01-18-2013, 11:20 PM
Hey guys, this is my first technical thread, so bare with me please. I am finishing up a motor build for my 90 sc 5 speed and I am wondering what would anyone's recommendation be on how much over drive would be good for my car. Here are my modifications:

.30 over Wiseco pistons with 94 rods
stock crank
custom grind cam, springs, and pushrods from DD
home port and polished heads
5 angle valve job
75MM tb
port matched intake to 75MM tb
76MM MAF
42 pound injectors
255lph walbro fuel pump
chip from DD
gasket set and arp head studs from DD
3" cai
front mount intercooler w/2.75" piping
ported exhaust manifolds
full 2.5 catless exhaust w/megan racing mufflers
Sniper wet nitrous system (not sure on what shot yet, or if I'm even going to spray it or not)

Stock blower for now with 5% pulley and some port work, I don't have the money right now for a better blower, so for now, I'll have to run this blower. I was thinking maybe a 10% jackshaft pulley with my 5% sc pulley? I'd love to hear some opinions from some guys that have the similar set up! any input on what else I should or anything would be great, thanks in advance!

i suggest a 5% jackshaft pulley, But i wouldnt go no more then 10% od overall, i have been told 10 is to much for some cars, but you have that fmic, so i think a 5% jackshaft pulley would be perfect instead of the 10.

smith181992
01-18-2013, 11:20 PM
Ok, so no real benefit from more than 10% on a stock blower. That's good to know, I'll try that and see how it works. Would you have an estimation on hp and torque with what I have? I'm really excited to get it going again :)

aroot1
01-19-2013, 08:55 AM
If cash is tight, a late model blower is a nice upgrade for early cars if you watch for a good deal. Couple hundered at most, and a double intercooler (with a fan) also helps greatly with heat, which may alow you to step to 10% from 5, or even 15 (with the late model) from 10.

Adam

91BLOWNBIRD
01-19-2013, 02:01 PM
He won't need a double IC cause he has a FMIC

Late model blower isn't a bad idea though...10% with a late model is better

aroot1
01-19-2013, 03:35 PM
[QUOTE=91BLOWNBIRD;1019487]He won't need a double IC cause he has a FMIC

DOH!!!! Missed that. With a good fmic 15% on the late model blower would work, especially if used with a MP inlet

Adam

Scott Long
01-19-2013, 07:21 PM
I'd leave the stock blower at 5% its currently at, and save up for a late model. Then add the 10% jackshaft to the 5% pulley you have tranfer over to late model, and port the late model. Of course it'd make more power on an MP inlet but those are hard to find and from what I hear may not be made anymore after this last group buy.

smith181992
01-20-2013, 12:06 AM
Yea, I know about the late model blowers, but all the ones I've seen are going for like $400, and for that amount of cash, I just see save up for a whipple :) So I think I'm gonna do what you guys are saying and run the 5% for now until I save up the cash an upgraded one....of course, then I'm sure ill have to upgrade my MAF, tb, fuel injectors, and tune again...so it'll be a while before I can upgrade further!

91BLOWNBIRD
01-20-2013, 03:55 AM
Yea, I know about the late model blowers, but all the ones I've seen are going for like $400, and for that amount of cash, I just see save up for a whipple :)

Lol that's funny

Scott Long
01-20-2013, 05:32 PM
$400 vs $2200+ mounting, fuel rail, injectors, maf, tb, fmic, tune...

I'd say the late model is great bang for the buck.

smith181992
01-20-2013, 10:45 PM
Well...if your gonna upgrade, why not go big, right? Are you saying that a late model blower can give me just as much performance as a whipple? Cause I wouldn't think so.

Scott Long
01-20-2013, 11:47 PM
Well no, it will not, however you can bolt it on for a minimal investment. All you'd need is the late model blower and inlet plenum, some slightly larger injectors like 36's or 42's, and a maf w/ the right sampling tube and/or preferably a tune.

Or you could get a whipple for $2000+, have to fab up a support bracket to mount it, custom fuel rails and lines, huge injectors, throttle body, maf, intercooler, tune, no sense putting it on a stock motor so at a minimum i'd recommend cam and ported big valve heads and roller rockers, then you'd need headers and exhaust system to let it breathe. So after dumping $5000-6000 you can have that, or you could spend like $600 and get the late model and be driving it with more horsepower and enjoy it sooner.

So for 1/10th the cost you can have more fun with that car sooner.

It's all about priorities though.

You can then get the late model ported, and build a front mount kit, get the exhaust upgraded and then later on do a whipple (if you can even find one).

You don't just swap an m90 for a whipple and get 500 hp. Not that simple

smith181992
01-21-2013, 02:08 AM
I definitely see where your coming from. I know you don't just bolt it on that easy, I've built my car from the ground up, so I'm not stupid. I know I'll have to fabricate a lot of stuff and have already planned to send one of my extra set of heads to DD and let him do his magic with them and send me a bigger cam etc, etc...of course, I'm sure by the time I do have the money to spend for one...I won't be able to find one, lol

aroot1
01-21-2013, 09:40 AM
Rebuilt and ported late model just sold on e-bay for $310 shipped. If you r not doing injectors, its a 1/2 hr swap. Then you can drive it till you get all your pcs for the whipple, sell it and just about break even. For me, I'm cheep (used to call it thrifty, and it was a good thing when I was in boy scouts:cool:), it's a no brainer.

Adam

smith181992
01-21-2013, 07:45 PM
$310? :eek: Well now I feel stupid...lol, If I could find one that cheap, I will definitely have one! I've just seen people asking 400 or so for them and assumed thats what they went for. I'll probably post looking for one when I recover from this last big spend on my motor :)

90tbirdsc
01-21-2013, 09:26 PM
I bought my late model off eBay for $130 shipped. I spent 400 on porting and having the rotors recoated,sound ports closed,new coupler and all new bearings and seals. I also bought a mp inlet and 75mm tb. With the fuel system upgrades I have this swap should yield a easy 1.5 seconds off the quarter with my fmic. If you find some stuff used you can go from stock to ported late model with 42# injectors 255lph fuel pump and cai and maf and tb for a little over a grand. Pretty good bang for the buck mods.

nickleman60
01-21-2013, 09:52 PM
$400 vs $2200+ mounting, fuel rail, injectors, maf, tb, fmic, tune...

I'd say the late model is great bang for the buck.

You better double that Whipple estimate son..........:eek:

Scott Long
01-21-2013, 10:07 PM
wow.... can you just get a whipple by itself or do you need to buy it as part of a kit for another car like a mustang and sell off the other parts you can't use?

smith181992
01-21-2013, 10:13 PM
I bought my late model off eBay for $130 shipped. I spent 400 on porting and having the rotors recoated,sound ports closed,new coupler and all new bearings and seals. I also bought a mp inlet and 75mm tb. With the fuel system upgrades I have this swap should yield a easy 1.5 seconds off the quarter with my fmic. If you find some stuff used you can go from stock to ported late model with 42# injectors 255lph fuel pump and cai and maf and tb for a little over a grand. Pretty good bang for the buck mods.


So do you think I could get a late model blower with a mp inlet without having to upgrade maf, tb, and injectors again since I already have 75MM tb, 76MM maf, and 42# injectors? (My full list of mods is the first post on this thread) because if I don't have to upgrade all of that again, I'll definitely get one! :cool:

smith181992
01-21-2013, 10:14 PM
wow.... can you just get a whipple by itself or do you need to buy it as part of a kit for another car like a mustang and sell off the other parts you can't use?

Was gonna be my exact question Scott :rolleyes:

Scott Long
01-21-2013, 11:08 PM
So do you think I could get a late model blower with a mp inlet without having to upgrade maf, tb, and injectors again since I already have 75MM tb, 76MM maf, and 42# injectors? (My full list of mods is the first post on this thread) because if I don't have to upgrade all of that again, I'll definitely get one! :cool:

Yeah you'll be fine if you are already tuned for the 42's.

nickleman60
01-22-2013, 08:25 AM
wow.... can you just get a whipple by itself or do you need to buy it as part of a kit for another car like a mustang and sell off the other parts you can't use?

Sure you can but you have to have a custom intake made along with other custom parts for it to work/fit a supercoupe and that ain't cheap...........;)

aroot1
01-22-2013, 05:31 PM
http://www.ebay.com/itm/160959539023?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1438.l2649

4 days left on e-bay rite now. currently $150+shipping. As mentioned above better intake will help greatly, as will porting, just adds $$$ if on a budget, stock is still better than early stuff. Also budgeting for solid coupling/snout rebuild is a good plan, not all sellers are honest:cool:

Adam

David Neibert
01-22-2013, 05:46 PM
I'd get a 10% JS pulley and see how much boost it makes...if over 15 change the supercharger pulley back to stock (early model) to lower it some. Same parts will be needed when switching over to a late model so you won't be wasting the money. Big advantage to the late model supercharger, is being able to use the much larger MP inlet plenum.

David

smith181992
01-22-2013, 09:02 PM
http://www.ebay.com/itm/160959539023?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1438.l2649

4 days left on e-bay rite now. currently $150+shipping. As mentioned above better intake will help greatly, as will porting, just adds $$$ if on a budget, stock is still better than early stuff. Also budgeting for solid coupling/snout rebuild is a good plan, not all sellers are honest:cool:

Adam

Wish I had the money for it right now, I'd put a bid in! I'm gonna buy one though when I can...right now I just want it going again!