Rocksiroc

I have an 86 iroc z and want to get more power out of it. I want it to make over 300 hp and would like peoples input on how to get there. I was thinking on upgrading the following.

Cam (comp cams xe262h)
Heads
port stock tpi set up
headers
already have flowmaster catback


Do u think these mods would get me there or would i need to spray it.

battman

iTrader: (2)

spray it

tenpin842

yup agreed.....thats the only way our going to get to 300 hp unless you redo the bottom end.
I think stock is only 190hp and thats at the motor.

Do all thoes mods....then toss a 100 shot on it.
My brother in law sprayed a 150 wet shot all the way down the 1/4 mile track. But hes got a 89 GTA with the 5.7 tpi.
Not sure if I'd do that to a 305 though. 100 should be just fine.

I did all my mods and im over 100 away (at the rear tires)

Rocksiroc

I meant over 300 at the flywheel

1MeanZ

iTrader: (9)

You really have no clue do you? Get your facts straight before you start posting on here. theres already enough bad info around here. This is why I rarely post on here anymore.

You do NOT need to get in the bottom end to get 300hp out of a 305. All it takes is headers, exhaust, cam, and heads, thats it. if you have a MAF car you won't even need a tune, although it would help. Do a search for my screen name, you'll find hundreds of 305 posts and what I did. Also do a search for mw66nova, tunedport335, tim burgess, sitting bull, madmax, and wishmaster'sIROCZ just to name a few. All of those guys have or have had mean 305s. 300hp is just a heads and cam swap away, it's that simple.

And about a 305 taking nitrous, lots of guys run 150 shots and have no issues.

Dale

iTrader: (12)

I belive its around 205 or 215 depending on the year.

You should beable to get a 100 more with full exhaust, cam, heads, injectors, and a few other small things.

Dont forget to mod the chassis and suspension. You can re-gain lost HP by fixing/replacing some of them parts.

Just pick your parts wisely so that the car is still reliable.

tenpin842

Pretty funny you say that.....I dynoed at 178rwhp. (on a mustang dyno) And I have the sheet to proove it. So you tell me I toss a set of heads on and Im going to gain 122hp??? Look at my sig. Even my best 1/4 mile time was 14.8 with a 2.1 60'. I know the bottom end of my motor has 100,000 miles on it but I still had 145 +/- 5% al all my cylinders when I did a compression test.
Yeah thats funny for sure. Maybe you shouldnt post here at all if all you can do is insult people.

flaming-ford

iTrader: (7)

todd i just figured i'd let you know that yours is making a significant ammount more power than what your dyno sheet says, if you're wondering y, heres 2 reasons 4 u (no offense meant just trying to shed some light).

#1 you've got an automatic, theres no telling how much youre torque converter was slipping as you were making that run, unless of course you forced it in to lockup which i doubt but, could be wrong.

#2 you ran a 2nd gear pull as opposed to your 1 to 1 ratio 3rd gear, basically that alone would probably give you a 200 hp pull + the difference of torque converter slip and perfection tune my opinion is you'd probably have a true 220-240 wheel hp if you forced lockup, and ran a 3rd gear pull with a perfect tune

anyways to the orignial poster, yes i think a well tuned tpi setup with a cam close to the 262 you posted and a set of world product heads can easily obtain a 300 fwhp #, more so i think it's quite possible for them to even obtain that # at wheels with adequate, fueling, timing, heads, cam, ported intake.

anyways heres a little food for thought on a head/cam 305 build (it's not tpi) of course so it wouldn't quite make the same power but, you get the gist

http://www.popularhotrodding.com/eng...o_testing.html

i'd say with tpi and perfect tuning you'd get about 320 hp out of that setup just my opinion though.

anyways good luck with your build either way its easy to make them a lot faster than the factory even intended.

Kawtipping

Stock HP on my 92 305 TPI was somewhere around 205-215 depending on what source you believe. That is flywheel horse though. As for 300 hp out of one, I don't think it would be all that difficult. Heads are easily worth 50-60 hp (with proper tuning). Combine that with a properly selected cam (and again, more tuning), and the goal of 300 should be reached easily. If you are running an auto, ditch the stock converter because you will be outside the designed power curve. Once again, tuning is everything!

Fast355

iTrader: (2)

Enough to make a 5,500 lbs G20 van with 3.08 gears do this.

tenpin842

wow.....glad my speedo goes to 140

But thats nice!!! thats a heavy van!

Fast355

iTrader: (2)

Yeah I know, picks it up like it aint even there(for a van anyway). I've cruised it about 5 miles @ triple digits last night. Never dropped out of OD.

Guest

Supercharge it.

300 at the flywheel shouldnt be difficult, I'm certain I'm way past that point. The engine itself is a stock 91 TPI, from throttle body to oil pan (except the hole in the oil pan for drainback). But there's other ways to get power out of a 305, just like out of a 350. Unless there's some specific reason to run a 305 though, make sure whatever you buy will work with a 350 or larger because if/when that 305 ever lets go there isnt much point fixing it when 350 blocks are dime a dozen and will yield more power with less effort than a 305.

FYI this motor I have has been supercharged for many many miles and its only ailment is valve stem seals which is just because its a SBC. I'm sure my rings and head gaskets are hating life about now but so far its all ok.

tenpin842

omg...thats great! People try to knock 305's but its been a pretty good motor to me so far.
And Yes.....everything ive got.....will swap over to a 350 when I get ready for it.

Brisk

iTrader: (25)

305's came make power, its all about matching your parts so they work well together

i_love_thirdgen

iTrader: (3)

this is off subject but Kawtipping i'm in New berlin, Wi too... where around nb are you at and have I seen your car aound?

1MeanZ

iTrader: (9)

I said you do not have to get into the bottom end of a 305 to make 300hp at the flywheel, did you read my post? You said you have to get into the bottom end, and thats not true, thats why you got the response from me that you did. You further display your intelligence by telling me all about your wheel horsepower dyno numbers when we are talking about flywheel horsepower. Anyone on here that has built one knows that you dont need to get into the bottom end to make 300hp. What you said was simply untrue.

tenpin842

Where in this thread were we talking about 300hp at the motor or at the rear tires?
No where in your post did you say at the flywheel or the rear wheels.
I was the 1st to post (at the rear tires)
this was the VERY 1st post:
I have an 86 iroc z and want to get more power out of it. I want it to make over 300 hp and would like peoples input on how to get there. I was thinking on upgrading the following.
Cam (comp cams xe262h)
Heads, port stock tpi set up,headers,already have flowmaster catback
Do u think these mods would get me there or would i need to spray it.

Brisk

iTrader: (25)

tenpin842

lol....that was after my post.

Rocksiroc

Ive been researching parts and wanted to see what u guys thought of this combo.

World products s/r heads, 170 cc runners, 58 cc combustion chambers
Crane energizer roller rockers 1.6 ratio
comp cams pushrods
12-262-4 comp cams cam, lifter and timing set kit
edelbrock tes headers
Maybe an accel superram intake setup if needed, or could i just port the stock tpi intake setup.

Do u guys think this combo is good, and will make over 300 flywheel horsepower.

tenpin842

Sounds nice....make sure you get matching springs to go with that cam though.
Also check for clearance with your valve covers. Some center bolt covers dont like a large lift LOL.

CoreyRI

http://www.goingfaster.com/spo/carcraft325hp305.html

check that out

oh and i believe its the low output 305

MidnightBlue07

I'm not trying to be off topic but I too have an 86' Iroc-Z and I'm also wondering if the setup I have for my car could possibilty reach 300 fwhp or close to that.

also what about 1/4 ET time do you think I could also reach?

BTW Tenpin, how do you like your 3:73 gears on your car cuz I been thinking of changing mine over , but not sure what gear ratio to decide.

1MeanZ

iTrader: (9)

looks like you have an OK setup, I'd just port the stock heads or slap L98s on it and you'll be there.

tenpin842

I love my 3:73, still drive on the highway at 2500rpm's at about 70mph.
I'm still in 3rd gear by the end of the 1/4 mile.
And its great for around town. I had to get used to it though, big jump from the stock 2:72.
1st gear is a quick one. If I had a 5 speed though....I would have went with a 4:11.

Zepher

iTrader: (1)

you do not want a 5 speed with 4.10 gears. you have no top end, no 1st gear, and your highway mileage suffers.
I've had 3.27, 3.42, 3.73, and 4.10's with my 5 speed.

Below, I had approx. 275HP at the flywheel, give or take a few.
this was my 86 Trans Am LG4 that I swapped from carb to TPI with a cam, headers, full exhaust, and a 3.27 gear (can't remember if I had the 4th gen 3.42 rear at the time).
http://youtube.com/watch?v=nGTLJ9nS2aI

A quick run on the highway with an oil leak,
http://youtube.com/watch?v=iJ8DqoSvQ9E

tenpin842

Yeah but u will be 1 quick SOB from street light to street light!

MidnightBlue07

Yeah you will!

Zepher

iTrader: (1)

This is one of the few vids I have when I had the 4.10's in the car.
I am in second gear then entire course and tach it up to about 5K rpm on the majority of the course. 3.73's would have been ideal for this course.
http://youtube.com/watch?v=szoYOMoO8b4

stevo the torpe

wow wow who says they have 373s at 70 and 2500rpm if its auto someones lieing

tenpin842

LOL.....sorry a GPS doesn't lie. Better do some searching.
3:73 gear with a 700r4 IS 70 mph @ 2500rpm in 4th gear. Sorry to burst your bubble.
(LOL...I just went out to double check again)

stevo the torpe

u must not have 373s i have a 91 camaro 350 700r4 373s with stock height tires and about 70 340r3500 rpms in fourth gear the 273s did 2500 70 so ur stock

tenpin842

LOL....I could go 80mph at about 1500rpms with my stock gears.
You want them....I still have them in the Richmond box.
Want my gear #?
49-0007-1

I think somethings messed up on your car.

Tobias05

yeah man, 2.73s suck.

FWIW ~2300RPM @ 70MPH, 4th gear lockup, 3.42s, 26" tire.

tenpin842

Well I have 17" TTII's 245/45/R17 tires.
I have a 3:73 gear.....I still have the box. I have a 10 bolt 7 5/8"

stevo the torpe

theres nothin wrong with my car ur tach must be set on 6 cilinder or something.eveen my girls 89 camaro does 2500rpms at 70 my brother has an 88 ss454 pickup 373 and it runs around 34an35rpm ive had a **** lode of third gen camaros ive had an 87 iroc tpi auto 700r4 327 gear.ive had a 85 camaro tpi auto 323 gears.and my 91 tbi auto 373 and an 89 mpi 2.8 auto 273s i no what camaros run.82-92 tell someone else
----------
and u prob aint got a progammable speedo do ya how do u no ur running 70?

tenpin842

Its called a GPS, ya know it connects to the satellites? It does tell you the MPH.
LOL...but yeah Your right I'm wrong.
Nope my tach is factory....might not be right on....buts its close.
My car shifts perfectly out of 1st at 5500 rpms, out of 2nd at 5800rpms.
Never had it going fast enough to shift out of 3rd with my new shift kit.
Ive only had it to the 1/4 mile track. Yeah the tracks ET must be off too....because I was still in 3rd gear at the end on the 1/4 mile track trapping 93mph.
Say what you want....I know my car and what I bought and installed for it.

stevo the torpe

350 out of an 88 chevy pickup,cam,ported heads,700r42400 stall 373 motive gears detriot locker 28 spline axles moser,hedman headers,flowmaster 40 series.lakewood traction bars all new energy bushings,koni drag shocks,b&m shifter,be cool rad,optima red top,autometer phantom gauges,black racing seats,,and then what iam building for it 350 bored 30 over 400 eagle forged crank,eagle h beam rods, kb forged p -12 cc 64cc head 10-01, file fit rings 234-234cam 488-488 lift,64 cc jegs aluminum tpi intake ported tci damper as well as 400 flyweel twin turbo kit 2 t4 7psi adjusteble bov,cap hp 450 each,torq thrust II 17by9anhalf 17by8 kumho esta supra treds

tenpin842

Guest

2500rpm with those tires calcs out to about 73MPH.

Handheld real time GPS technically isnt accurate enough to determine an accurate speed... but they do a decent job. I think your tach is ballpark enough accurate.

tenpin842

LOL....thx Max, I knew I wasn't losing my mind. I knew I was close though.

stevo the torpe

same weels as mine 17by 9.5 and17by 8 ?

tenpin842

I've got 17x8 all the way around.

Zepher

iTrader: (1)

I found this cool page where you can input your engine and car data and see some cool info,
http://craig.backfire.ca/pages/autos/speed-calculator

I did mine with the 3.42 gears:
Tire Diameter is 25.66in
RPM @ 60mph in Top Gear: 1989RPM

Rev-limited top speeds in each gear:
1: 40.59mph
2: 57.53mph
3: 83.29mph
4: 111.61mph
5: 150.83mph


Lowest gear to do 60mph: 3
Lowest gear to do 100mph: 4
Transmission Ratio Spread: 3.72
Driveline Torque Multiplication
1: 9.40:1
2: 6.63:1
3: 4.58:1
4: 3.42:1
5: 2.53:1

and with the 4.10 gears
Tire Diameter is 25.66in
RPM @ 60mph in Top Gear: 2384RPM

Rev-limited top speeds in each gear:
1: 33.85mph
2: 47.99mph
3: 69.48mph
4: 93.10mph
5: 125.81mph


Lowest gear to do 60mph: 3
Lowest gear to do 100mph: 5
Transmission Ratio Spread: 3.72
Driveline Torque Multiplication
1: 11.27:1
2: 7.95:1
3: 5.49:1
4: 4.10:1
5: 3.03:1

mnorton

Tenpin,
I've been giving some thought to your recent dyno numbers. I realize that when discussing combo's, it's not easy to speculate which mods give exactly what gains, but just to try, let's talk "flywheel" HP.

You dyno'd at 178 HP (@ the wheels), and the conversion loss for an automatic transmission is ~20%, which would put you at 222 HP @ the flywheel. That's 78 HP away from reaching 300 HP.

It looks to me like the stock flywheel HP rating for your engine is 190 HP @ 4000 RPM, and that the 1987 LB9's which got the "better cam" were rated at 215 HP @ 4400 RPM, (25 HP more). This seems to indicate that your cam swap alone has gained you at least "that 25 HP", maybe more...

With your new cam in place, I suspect that just a set of better heads would provide you with another 25-30 HP, which would then push your numbers up to 250+ HP.

With a new set of heads, the upgraded intake, fueling, and exhaust that you already have in place, and a PROM tune that would make use of those upgrades, you should be looking at well over 250 HP. Throw on a set of Roller Rockers (~5 HP gain), and you're at maybe 275+ HP @ 4800 RPM?

I also suspect that when the factory dyno'd these engines, they did it on a dyno stand with a good airflow and exhaust system in place. Probably better than what came stock on our cars.... but still it's pretty certain that they did use the stock exhaust manifolds. So I'm sure that a good set of headers (like you already have) does improve the numbers.

I believe that when I installed the 2032 cam and World heads in my engine, the power peak moved up a solid 400+ RPM. I'm sure the same thing would happen in your case, maybe even be more pronounced since you have a higher airflow intake system than I do. Then again I have 3:45 gears, and you are running 3:73's so your power peak may be at a different RPM than mine.

Typically, with a higher RPM power peak, comes higher peak HP. (Just look at the stock HP specs...4000-vs-4400 RPM)

Bottom line is; that I believe your stock heads are currently the bottleneck in your system, they just don't flow well enough, and are holding back the gains that ALL of your other existing upgrades could bring.

It seems that all of you "automatic transmission guys" also eventually install higher RPM Stall Converters to match the higher engine power output... Just more food for thought.

So basically I agree that it aint all that easy to get 300 HP from these LB9 (TPI) engines, but still, using the stock rotating assembly, and with the right set of mods, you can get really close, maybe some of us even get there!

tenpin842

Thx mark, Yes I do agree with you there.

stevo the torpe

there are several ways to find out ur gear ratio assuming u have a 26 inch tireyou can travel at 70 in the 1;1 ratio 3rd gear in 700r4 and t5 in fourth.when u reach 70 and ur tach is right N RPM READING OF2730rpm wich is 273s and 3230 rpm would indicate 323,342,373

Fast355

iTrader: (2)

I dyno'd this engine yesterday on a Mustang Dyno.

240 RWHP @ 5,000
329 RWTQ @ 3,600

At 2,700 when the AE finally leaned-out after the first hit of the throttle @ 2,500, the engine made 250 RWTQ.

figgynuton

Not trying to bag on you at all! But i have a buddy who has a 305 TBI With a THM-700R4 And a all stock rear end. With only a magnaflow exhaust and a very mild mild cam. Oh and race fuel! And He does 14.7 in a 1/4 mile. Now i am not calling you a liar or trying to insult you whatsoever but i do believe if you did all of those upgrades in your signature "I" think you would have run a better time.


Perhaps your set up isn't matched up all that great?