the Roc-Z28

Hey I would like to add some major horsepower to my 87 5.0 iroc and was thinking about getting nitrous but was advised against that, do to its age and mileage (107,000 mi) And was steered towards getting a supercharger instead. So I need help picking a supercharger kit. or should I just go back to my original plan of nitrous?

fireturd350

iTrader: (8)

It depends on what you can afford IMO. Nitrous looks cheaper to start with but then you have to figure in how much you will use it. It's consumable so you'll have to find a refill station, travel there (gas prices), pay for the bottle to filled.

Vortech stopped carrying bolt-on kits. Procharger still carries kits designed for 3rd gens. www.procharger.com You'll probably be looking at $4000 to $6000 depending on the kit you select and where you get it from. The self-contained units still have to have the oil changed in them so figure that into the price of running them as well.

the Roc-Z28

Will a supercharger for a 5.7 work on my 5.0?

fireturd350

iTrader: (8)

Yes it should. You would probably see extra boost pulley to pulley due to the lesser cubic inch. I believe Willie might have been running a 305 for awhile.

one wheel peel

4-6 grand you could just buy a NEW crate motor for more hp

Zeeboinc

I have a Paxton SN-92 kit on my 89 Iroc 305, it's retarded fast (rapes new camaros, corvettes, mercedes AMG V12) but total has $15,500 in it (forged pistons, tpis intake, lingenfelter throttle body, AFR 190 heads, edlebrock tubular frame, yaddi yaddi yaddi, too much to list)

86Z

iTrader: (4)

how much boost? what did it dyno, run at the track?

Zeeboinc

The PO said it was 680hp and hawaii got rid of their track before I showed up on island, do to a bagillion tuning issues it'll be a min before I can get a dyno or track slip. Also the boost is at 10psi. PS: MPG is 8, lol.

86Z

iTrader: (4)

2 things, it's not a 305 or it is and it's not 680hp with those mod's...

Zeeboinc

I'm not saying it is just that the PO said that although its possible for it to be that at the crank because the AMG V12 has 518 rwhp and the iroc made it look like a civic. My wife even smoked a 10' Camaro SS by 180ft in 1 city block, I'm not trying to brag I'm just suggesting a particular supercharger for his 305.

Street Lethal

iTrader: (16)

Unfortunately I would have to agree, that would pretty much not be the case with that setup at only 10-psi of boost, not to mention with a bagillion tuning issues along with it. That would somehow imply that with a good tune, the car would make over 700-HP, which is simply not going to happen at 10-psi. Also, 10-psi equates to about 68% additional horsepower, which is more than likely what the PO meant, not the actual horsepower itself. Do the math, 680-HP would be with the 68% power gain at 10-psi (10-psi multiplied by 6.802% = 68% increase), which would mean that your engine is somehow making 373-HP without the supercharger, because 68% equals 307 additional horsepower over the alleged 373-HP without the supercharger, and 373 (NA-HP) + 307 (boost-HP) equals the suggestion of 680-HP w/the supercharger at 10-psi. I don't see that happening....

Zeeboinc

Tuning issues are current (as of the move from hawaii to baltimore and after the blown headgasket and broken pushrod), the total setup is 305 .30 over, forged 2 valve relief flat top pistons (not sure brand), afr 190 heads, pro comp cam (not sure grind specs), LT1 headers, paxton sn-92 blower, underdrive pulley set, tpis intake, not sure #injectors, holley pro commander 950, 8an fuel lines (I believe that's the size) msd distributor/ blaster coil/ wires /6al box/ and boost retard,optima red top, hurst shifter, built T5 tranny (supposedly upgraded servos and yaddi yaddi), 3.73 rear gear, edlebrock tubular frame reinforcement, hotchkis torsion bar, koni adjustables, 4 wheel discs brakes on I wanna say 14inch slotted rotors. Like I said I don't know its actual numbers only the cars its beaten by both me and my wife. Granted that's only as valuable of info as the drivers in the cars but I'm just saying. Plus the tires will rip lose even in third at approx 50mph. However its currently in the garage due to the tune probs (fuel pump is limping, and the pro commander tune was erased and it keeps blowing the intake piping off so I'm gonna try a BOV. Once again I have no reason to brag I'm just offering my experience with a particular supercharger for the OP to consider. Obviously I'd love to know my actual numbers but that won't happen till I invest some loot in her to get her rolling again.

Street Lethal

iTrader: (16)

At 10-psi w/your current setup, the average power is definitely there, so although you may not be peaking anywhere near 680-700HP, your making enough constant power throughout your entire RPM band which is why she is hauling @ss....

86Z

iTrader: (4)

no harm, bragging is fine, just putting it back to reality.

Zeeboinc

Not trying to nit pick (actually trying to learn something) Assuming the 6.802 is a constant for measuring the boost and figuring the % increase is correct and moving on to the rest of the calculation I believe your math is a little off. 68% of 373 = 253 (rounded) not 307. Percentage calculation is as follows:
Part...... %
----- ------
Whole..... 100

Part x 100 / whole =%

ie.

253...... 68%
---- -----
373...... 100

where as 307 would be:

307...... 82%
---- -----
373...... 100

Like i said Im not ******* you or nit picking I'm just trying to clarify the calculation because it's good knowledge. If I'm incorrect please feel free to point out where. However i would like to thank you for your senior knowledge on this topic.

Street Lethal

iTrader: (16)

That is completely besides the point, as my little mistake by hitting the wrong key only makes your suggested 680 horsepower figure even more harder to believe using now the correct figures. Forget about 373, as that number is now completely irrelevant, so there is no reason for you to even be using that figure. You should have figured this out all on your own just knowing that, so therein lies your mistake. The real figure is 405 naturally aspirated horsepower, not 373, which there is no way that you are making naturally aspirated....

1-psi divided by 14.7 (atmospheric pressure) = 6.802%, and 6.802% is the amount of additional fuel and air the engine will consume with every pound of boost. So the real calculation is as follows....;

10-psi times 6.802% = 68.02%
68.02% of 405 = 275.49
405 (NA) + 275 (boosted @ 10-psi) = 680

.... do you really think your engine is making 405 horsepower w/out boost?

fireturd350

iTrader: (8)

Bolt on Superchargers cost some cash unless you pick them up used. There are acouple on the classifieds section.

They were around far before turbo kits became popular in the past years. Most people say you can build a decent budget turbo kit for $1500-$2000 depending on what you're expecting to do. Course that means you're going to be doing a lot more than just bolting something together following directions. Don't expect to just use the cheap bolt-on $1000 turbo kits off eBay without redoing the headers or other problems with housing seperating.

Either way don't expect the car to perform to well without the normal bolt-ons upgrades like reallocation LCA brackets and etc. You can be making a ton of power but it's not going to transfer well without the proper suspension and chassis setup.

jkrustchinsky

well im bolting a b&m 144 to my factory 305, i just bought it used, im waiting for the rebuild kit in the mail. blok is .0030 low mileage after rebuilt. ill run about 5psi at first,

freaky

you ain't gonna get but 350 hp out of a n/a 305 . 10 psi of boost is about 200 hp that equals to 550 at the crank .minus 15% drivetrain loss an the best you can hope for is 467 at the wheels .unless your adding nitrous you won't see anywhere closs to 680 for real

Zeeboinc

Did I catch you on a bad day? I don't see why your getting so mad Street Lethal I was asking you a question not criticizing you. Once again I'm not saying my car is making 680hp. I was clarifying the calculation for figuring out/estimating hp when adding boost.as far as me figuring it out on my own you just told me about the calculation yesterday. I had no clue about the 6.802 constant for this calc. As far as the original question by The Roc Z28 another route I would assume working well is using 2 EVO III turbos, they are quality mitsubishi OEM turbos and can be had for around 500 bux each from extremepsi.com 1 EVO turbo can bring a 4G63 (eclipse/Talon/Evo) engine (NA- 140hp) to the 380hp mark (based on air flow abilities). Obviously supporting mods are needed as always but an ebay intercooler/piping kit can be had for less than 200 bux, as far as BOV I would recommend something in at least 50mm trim if not 2 of em (ebay junkies can be had for 70 bux with a 6inch 3"diameter flanged pipe) or a more reliable, less boost leaking (and expensive) Tial 50mm for the 250ish range. Then ull need a boost controller, boost gauge, fuel pump, injectors, most likely cam and pistons (if I recall hyperueteric pistons don't hold up well to boost hence the recommendation of forged pistons) and a good tune(either new chip for ur comp or a stand alone unit. The boost gauge and controllers can be had really cheap on good ole ebay and a pump should be around 100 (I know the walbro 255 is always around 100 but 2 may be better then one depending on ur engines fuel comsumption). O and an AFR is always good to have on board. You don't wanna run lean!

the Roc-Z28

Okay so turbo almost sounds like a good idea but most people that I've seen who did turbos redid their headers themselves. Do they just need to be stronger headers or do they need to be modified to work with a turbo? If so does someone sell modified headers? Also I've heard that you always have more problems with turbos than with superchargers. fireturd350 said that their would be housing issues? What would I have to do about that? and if I do go with turbos you said that I'd need a new cam. What is a good cam size for me? Oh and what kind of roller rockers would fit on my car? What siz injectors would I need? And how much is a stand alone unit?

Sorry just lots of ?'s. please be patient with me

Thanks very much

freaky

i'd go turbo myself a single mp 70 will get you started very well or you could go with twin 57 trims . , look up dynamic efi on there websight for the ecu as far as injectors go with a tbi off a 454 you can tune out whats not needed with the ecu . get a wideband to make sure your a/f ratio stay around 11.4 wot .

fireturd350

iTrader: (8)

I was talking about the quality issues on the cheap ebay turbos.

Zeeboinc

If I recall correctly each pound of injector is capable of supporting 10hp. I.e. 30# injector=300 hp. As far as manifold they sell turbo manifolds for around 150 a pair on ebay, I don't know of their quality but I can't imagine they could mess up metal piping too much, lol. Stans alone comp can be rather expensive and I know you can burn chips and reprom ur own comp although I muyslef am not familar with it. A holley pro commander 950 kit is around 1600 bux but its tunable while ur driving and u can save multiple tunes (example) a DD low hp good mpg tune and a "hey this guy thinks he's tough next to me at this red light" all out drag tune. This way drivability and idle are great but you switch into beast mode. Granted you'll need a laptop in the car with you too.you can pretty much do the same thing with a good boost controller as well like the AEM Truboost which is a boost gauge/controller with pushbuttons so u can turn the boost up or down at will. Once again things get pricey when u buy good products as that gauge/controller is around 250 bux.

the Roc-Z28

will ls1 turbo manifolds work on my car?

Zeeboinc

I believe your heads have the exhaust ports spaced differently ( #1 then 2 together in the middle(#3 & #5) then #7, whereas the LS1 is evenly spaced out, IIRC).

the Roc-Z28

Would the T3 turbo manifold that came up on ebay work with the evo 3 turbo or would I need an adapter?

Shadow Z

iTrader: (2)

Honestly, just do what someone else mentioned, and put your money into a new, stout crate engine.

Drop 6K on this 400HP 350 crate engine from engine factory, and guaranteed compared to your 305, you would need clean drawers after you nailed it, maybe a new transmission too.

http://www.enginefactory.com/400hp.htm

Around 1,500 for a level 3 700R4 from Bowtie Overdrives, rated to 630 LB-FT of torque.

http://www.bowtieoverdrives.com/cata...m.php?ITEMID=9

So for 8K, if you have the means, there's a reliable 400HP for you. Rear wouldn't hold for long if you launched it with any decent tires, but it would be a fun, fast, reliable cruiser. Expecting 20 MPG wouldn't even be too crazy. Plus with at least 320 RWHP, you could whoop my Slowstang.

There, insanely better option than messing around with trying to get power out of a 305. And if that isn't enough for you, the same company also offers a 500HP street/strip 383 stroker for $9,600. Then a 600HP 502 big block for just below 15K, an 850HP 632 big block stroker for over 20K. So, there are cheaper, more rewarding, simpler options than messing with a 305. Especially if you (No offense intended) don't understand the basics of the parts involved with forced induction. Honestly, I wouldn't supercharge or turbo a 305 either. Besides bolting on a blow through carb, HSR, or a very well setup TPI system, there aren't many options. Then if you want it done right, you need to have turbo headers fabbed up.

At that point, a centrifugal supercharger seems like the only half way decent, easy way out. But on a stock internal 305, why even bother? Get yourself a hot crate engine. If you're power hungry after that, start with a 75 shot of nitrous. Still power hungry, climb to a 100, 125, 150 shot, just try not to blow it.

Zeeboinc

I'd have to agree with Shadow Z on this one monetarily/reliability wise; unless like everyone else on this forum you want the satisfaction and knowledge of building something yourself. Another route could be to get some universal power adder stuff i.e. turbo/supercharger, BOV, gauges, lines, pumps, injectors/carb, yaddi yaddi and build up ur 305 now while you save for a crate motor later which you can swap all the previously invested power adders onto.
As far as the T3 manifold goes I know the EVO III flange is a square four bolt with a large center circle for exhaust flow. Even if the flange was wrong a new one can be bought and welded on for very little (it's just a small piece of metal) or you can whip out the ole grinder and grind the inner edge to match the gasket and turbo flange (because if Im correct the T3 is a rounded rectangle port).

Not as a knock on Shadow Z by any means but if you want the satisfaction of "I built this" just start wrenching. Sure anyone can buy something already done (as I did when I bought my Iroc) but there's not much glory involved when people ask questions and you're like "well the guy before me did this" and "the guy before me did that" or "the guy before me said such and such" (hence why I'm starting to work on my own car now).

Shadow Z

iTrader: (2)

Then he can pay a visit to Eagle specialty products, and pick up a forged 383 stroker assembly, pick up a good 4 bolt 350 block, pay about 10K just to get a decent used cylinder boring machine, pay however much for a magnaflux machine, then get to work. What's the difference? Or pick up a crate engine and have it over and done with, then enjoy the car with no hassle.

There are two types of people when it comes to doing your own work. There are those that are educated and truly know what they're doing, and there are those that can't afford to have it done. I do oil changes and such, but I leave the bigger work to pros. I had my T56 swapped in, topped off with RP Synchromax, and the rear diff oil changed for $150. I had the IROC's engine, trans, and driveshaft pulled, plus the front bumper and fenders pulled off for only another $200.

The guy who swapped my T56 in owns an 11 second 2003 Cobra that he is now building a twin turbo setup for, and swapping to a built auto. The measly $150 to have work done by someone like that is worth it. My friend and his brother who pulled the engine and trans out of the IROC for me are involved in a family operated shop. They do it for a living, and they're prepared for that type of work everyday. Showed up at my house with a lift, jack, full set of tools, got to it and had it done in less than 2 hours. A measly $200 to save me from buying a lift, and spending a few hours at it, plus it helps out a friend by doing what he does for a living.

Tore the engine down myself after that, which didn't really make me feel like any more of a man. I personally don't think anyone needs to prove their manhood by picking up a wrench, even though to an extent, I know what I'm doing. I buy the cars to drive them, not to lay under them while they're on jack stands. However, no offense taken. The OP just honestly doesn't seem like he knows what he's getting himself into, so I showed him a link to a complete package that offers a lot of power.

The general population isn't going to know how to build their own turbo setup for a 305 powered third gen. There is a lot of custom fab work to be done. So... There's a 400 HP turn key 350 crate engine he could drop in instead. Saves a ton of hassle.

Shadow Z

iTrader: (2)

Also, good point there, but there is a huge difference in buying a car already built, and modding it yourself while having help doing the wrenching.

I bought my Slowstang as the typical 5 speed 99-04 GT with a Flowmaster catback, some gears, and a shifter. Now it has a 26 spline T56 6 speed swapped in, an SCT Livewire tuner, Centerforce DFX clutch, Fidanza flywheel, BBK O/R X pipe, 03-04 Cobra aluminum driveshaft, Steeda tri ax shifter. That's a few grand I've put into it myself. So, no questions at all about it are going to go unanswered, or with mentions of the previous owners.

Eventually it'll most likely be Procharged at about 10 PSI, fueled by an 03-04 Cobra tank with twin 255 Walbros and 60LB injectors, since they're about as high as you can go with a stock high impedance injector driver, so between the pumps and injectors, there's room to pulley it down in the future with a built short block. Won't be any unanswered questions then either. I do however need another daily driver before I go on a mission like that.

It's a shame that I missed out on an awesome deal before, or it'd be supercharged right now. Found a P1SC setup complete with intercooler and piping for $1,700. Head unit needed a rebuild so I wouldn't budge from $1,500.

Zeeboinc

I agree with the difference between buying a car done and modding one yourself (or at least with help of someone more well versed in the field). Thats pretty much what I was trying to get across. Of course you can also buy something mildly built which usually saves money bcuz you can get a car with lots of good high dollar extras at below value cost. I was just trying to get across that having something done entirely by someone else doesn't give you the same satisfaction as you get when you do it; or are at least involved in it. That's why I was suggesting getting the add ons to place onto the crate motor but starting with the learning how to put it all together using the current stock motor as a practice motor to get a feel for diagnosing and correcting problems with the engines performance/operation. Granted I'm no mechanic (although I'd like to think I'm a little more then a parts changer). Actually I'm a nurse in the Army, but simple things like Chilton manuals and forums like this can go a long way to teach someone how to care for (and abuse) their cars.