Hey Everyone.

Be prepared for a novel

Ive been sorta intermittent on this board, had alot of things change in my life, including picking up a 2nd project, moving and starting school to do Mechanical Engineering - Automotive Product Design.

Well, long story short, my iroc-z is currently a empty shell on a sketchy wooden cart sitting in the back of our shop, begging for some attention.
And attention it will get.

As it turns out, being in a school with a multiple million dollar machine shop has some benefits!

A short list of the machines we have at school:

5 axis CNC machines
Coordinate Measuring Machines
CNC Mandrel Bender
CNC Lathes
TONS of turret mills, manual lathes etc

During my CATIA credit times, ive decided to take advantage of my schools shop and make my iroc-z into something super.

Originally i had my sights on the LSX Shootout's "King of the street" (Fastest street car)

But ive since changed up my idea's, and ive decided a stupid fast car, that can hold its own in the twisties, drive comfortably, look stock, and rattle off a 9.99 at the end of the day.

Sounds like a hell of a project and believe me it will be!

Since im not rich at the moment, my first projects will be with the chassis.

Im going to repair any/all rust on the car, roll fenders, remove weight where safe to do so, and get working on my cage.

Plans for the cage is either a 10 or 12 point. Havent decided if i want to run the strut tower bars yet. Either way, i will design the cage in CATIA, and bend it here at school so that it tucks tight enough to the car that its hardly visible from the exterior of the car, and you can barely slip a finger between the cage and panels.

Also i will have the rear bars set in a way that they allow the retention of the rear seats. Not that they will be used, but this car has to look stock from every angle.

Seats will be stock, interior will look stock short of cluster and some strategically located gauges.

Idea's for exterior is a 91-92 Z28 look, but nothing that would hint theres much to the car. Perhaps some 18" wheels, so it just looks like a clean, slammed thirdgen with some nice wheels on it.

My chassis mods wont be too extensive. Cage will stiffen the car extensively, ill run coilovers on it, with 14" CTS-V brakes up front, then a 9" Differentiall with LS1 brakes (I scored a 9" Diff for $100, its sitting in the parking lot at residence :P ), ill have basic suspension compenents aftermarket, im aiming for a .9g skidpad, shouldnt be too hard, though the extra heft of the car may make things tough.

Inside& outside its going to look stock like mentioned above.

For the driveline, ive got everything pretty well thought out.

For the motor, its going to be forced induction obviously. Im not set on my motor at this point, only my forced induction system. Ill see what motor technology is avalilable when its time to build.

Its going to be a twin turbo setup, likely twin 70mm turbo's, they will dump to an X between the 2 then run 3" piping down to custom side pipes which i will modify the floors to allow to tuck up tight, then ill notch the GFX right before the rear wheels and ahve it exit right there. Similar to the Vipers. Ive figured out how to keep heat down from them so i dont bake the interior.

The turbo's will feed to a single FMIC which im going to have black so that you cant tell its turbo'd from the exterior, then it will run up to the intake.

Transmission will be automatic, likely 4L80e, then a heft driveshaft to 9" rear differential.


Few of the major projects that ill be doing at school:
-Cage
-Custom 1/8" steel wire bumper support to tuck intercooler and not do sketchy cutting of stock support
-Design for exhaust dump
-Turbo hot parts
-Turbo Cold side

Here's how she's lookin right now:



Its going to be a long build, but ill update all of it in here as i go. Its going to be a hell of a car ill build through college, then invest more when i finish school and settle into a job.

Thanks for readin guys!

 

Based on how fast you cranked out that Trans Am swap, I bet you'll be driving this thing in no time.

*subscribed*

And on a side note, I'm jealous of your career path. I wanted to do automotive design but the engineering school I went to my freshman year didn't really have a program for it, and I hated the school so now I am going to be graduating with a finance degree in December. Oh well...

 

Sick bro. I am subscribed as well! Look forward to seeing your progress.

 

subscribed for more updates. Sounds like a great project

 

Thanks everyone!

Nick - The program we've got here is pretty sweet, im still second guessing whether im going to stick here. Ive been mulling over the idea of heading out to the University of British Columbia to get a Masters in Mechatronics. Not sure if that will leave me more options in the end.

Here's the website for the program im in:

http://www.stclaircollege.ca/program...sec/mech_auto/

 

I'm going to offer some advice that may help you out in your project...

I like your ideas about the stock look and the upgrades that won't scream out "race car" - that is something people don't have restraint with these days.

4L80e is a bulletproof trans that costs a lot of $ to get it working right; a 4L60e or 700R4 will hold into the 700+hp range and may be all you need.

While a twin turbo is a great thing to have, it's not really a necessity on a 9.9 car, one that if you get into the 3200lb range only needs about 700hp to achieve. Since you have access to all these machines, why not build a 408 or 418ci LS3 that is going to put out about 600hp and then use a small nitrous kit to get you into the 9.90 range? There are plenty of high 10 second 346ci LS1 4th gens that run at 3600lbs, a lighter thirdgen with more power (more ci) would be at least in the mid 10's on the motor.

A stock IROC/Z28 on 275-40-17 rubber is going to corner in the .95g range, btw...

 

If you want a corner carver... why are you going automatic? I bet a T56 is lighter than a 4l80e too. Even better, a 5 speed TKO probably weighs less than a T56. But weight in the trans is hardly a terrible thing given it's low, centralized position in the car. If anything it might even help weight distribution so ...

But still, if your focus is on making a car that can corner go fast in a straight line, then go manual. if it's making a straight line car turn, go auto.

Of course, maybe you just mean "go around a corner" as opposed to "put up a respectable time around the nurburgring", in which case go with a failmatic.

 

Subscribed. As with the others, I like the idea of a clean "sleeper" look, kinda what I'm trying for, but you sound like you might be able to pull it off . I think this is what the new GM High Tech project car is aiming to be too, 'cept they are using a 4th gen.

If you really are trying to make a corner carver, definatly go with the T56, if for no other reason than 6 gears to choose from, you are more likely to have the 'right' gear available to you.

 

Awesome man, sounds like a nice plan...sorta where i wanted to go with my car but its turning more race than anything...but still can handle well.

I like the twin turbo idea.. build a big inch small block and you wont have to run much psi to get 9's. I'm at 10.3's with weak launch and 10psi with a rough tune. Probly has 9.90's as it sits with tuning and proper launch but 12-13psi will definately get me there on good tune.

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Hopefully that means i could throw this thing over 1g with all tubular suspension and coilovers!

As for Twin turbo, i know its not a necessity for a car of this caliber, but honestly, it means i can run smaller turbo's and have more precision over my spool up speed. Since i own all the tuning software, a key to making this car be more street friendly, but still wicked fast will be multiple tunes. I want it to be reliable, and able to make long cruises. A situation where 8psi would make a potential failure, much less likely to happen, also means meth is not needed. Say a street tune could be 12ish psi, i could run meth with that, and it would still be reliable to tear around town and whatnot, but its not going to put any heavy prolonged wear (meth) on the motor. As a pure hp setup, i figure 16-18psi at the track, where it see's 10seconds or less of max effort stress on the motor.

As for a nitrous motor, im not big into nitrous. I find a nitrous motor to be a bit of a dog on the street. However a multiple tune setup would correct this issue.

Either way, i want something thats more perminent, complicated and exciting. I know it wouldnt take much to build a bulletproof motor and spray a 300shot at it, but to build up a twin turbo motor, that is well put together and functions good i feel takes more engineering and is more respectful. Not to mention boost is always avaliable by getting your foot in it.

This is true. I guess thinking 1/4 mile wise, automatic is a better choise, but quite frankly, its not going to see as much 1/4 time as it will street/twisty duty.

I know one of the 6spd vette's i build made 949rwhp, and runs a 9.89@159mph. 6spd's tend to take more power for a given ET (sub12's i find) so as a 6spd, to meet my 1/4 goal, id have to make sure the motor is well over 1000hp @ the crank. honestly, no big deal, ive built 10+ vette's that made over 850rwhp. It doesnt take much with the LSx platform.

Thats true. Originally i had been thinking of a 454ci LSX block based motor. 6 bolt heads means reliable under boost, iron block means i aint gonna exceed its hp capacity, and 12psi of boost will be well over 900rwhp at 454ci. Hell, a buddy of mines 440ci warhawk TT vette makes 1161rwhp @17psi

 

Just be aware that any decent motor under 12 psi or so will be a bear to drive on the street...it wont hook up when you get on it. My motor drives around great but if you try to get down on the throttle under 50-55 mph in 3rd gear it will blow tires apart. Just a 3.42 gear and 295/30/19 street tires. 1st and 2nd gear are useless unless at the track. Lots of power but if it dont hook on the street its not gonna be a fun car to drive

 

Thats very true. 800rwhp i found to be a sweet spot in the vette's i built. At that power level it was still streetable, you could control the power and if you really had to, you could move around in a city environment without too much trouble. 6spd with slipable clutch makes that a bit easier.

900+ was more race power level, if you went out to pass someone and gave it some throttle to get moving to pass, you just passed them sideway.

 

sounds like a killer build. kinda what I wanted to do with this vert.

just decided on no turbos right now. Its listed in sig.
383 with novi 2000 pulled for 12psi

has spohn suspension parts and a ground control weight jack setup is next.

 

i dont think i'm much over 600whp through this converter/automatic and I have problems trying to hook while doing quick merges/pullouts from intersections to busy roads... its horrible lol

Driving around its tame as can be, actually too weak for me. But the turbos turn on very hard and very quick when you get on it, and it just spins tire. I cant imagine the 800+whp levels. maybe the stick shift is easier to control, but maybe not.

 

I have never heard nitrous motors having this problem - unless you have a 400hp engine that is built to take a 400hp nitrous hit to get quick ETs.

A 600hp stroked LSX motor with a 200hp nitrous hit is going to be in the 9's with the added advantage of controlling how much TQ hits the wheels.

 

I literally busted out laughing when I read that... Sounds like you'd definitely want a plastic interior that could be hosed off easily...


You guys are talking about stupid horsepower levels - but I love turbos as well. If I ever do anything with forced induction, it's not even a decision for me. (Gonna give away my age here, but...) When I was 17 or 18, I worked at a Buick dealership, right when the GNs & T-Type Regals were new. Oh man, was THAT a fun job sometimes! For me, there's just nothing for streetable power like a turbo.

 

Made a bit of a start to this project, ive got some more of the car apart, but its really going to start progress once i get my trans am out of the way.

Ive been working with my buddy who's an absolutly amazing drawer to get an idea of what id like the car to look like in the end.

This drawing here depicts the 18" iroc-z wheels which would be painted to look like stock wheels, shows the 91-92 Lip & Spoiler, and shows the exhaust tip in the GFX, however the exhaust tip would be larger and likely sit a little lower.



Ill keep this thread updated as i go. Im going to be making up Derlin bushings for the car at school, as well as fabricate new rear suspension parts.

 

where that exhaust tip is right where the floor is on these cars, how do you plan on running it like that?

 

Im going to be altering the floor structure of the car. Ive got a rough idea in my mind, im going to use ovalized tubing, though i know i will need to determine a way to conquer the same problem the vipers have of the exhaust tubing heating the floors up, and from there the interior, since it wont have a/c the last thing i want to be doing is introducing heat into the cabin

 

just insulate and wrap the pipes. I used it on my turbo motor and it does a fine job of insulating and isolating heat.

 

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Thats what i was thinking, only downfall to that is if the car is driven in wet weather their going to hold moisture to the pipes promoting rust in them. Unless i get some high quality stainless to run the exhaust with and then i wont have to worry about the piping rusting

 

They may hold alittle moisture if they get wet but the exhaust will get hot enough to evaporate it while driving. Stainless would work well if you can find it

IMO i wouldnt be driving this car in the wet

 

For the boost situation.

Im torn right now on what to do.

I think im going to rule a twin turbo out, its extra un needed work, and add's to the chance that i could have uneven boost between the turbo's, add's to costs etc.

MightMouse on LS1tech, '07/08 king of the street got himself there on a PT88 single turbo.

Precision turbo has since released a PT88 with a 91mm compressor side.

Im sure i can get over 1000rwhp with a PT88, only note with a turbo like that, is its spool up its going to be 4000+ rpm, which potentially is going to make it less streetable.

On the other hand, i could throw a Vortech V-7 YSi or Procharger F1-R on it, and the powerband would be a little more linear, potentially making it a little more streetable, and still a 9 second car.

Turbo is likely a little cheaper to do, both require custom exhaust work, as ill need a 1 7/8" header min with a blower.

PT88 turbo setup would be a 370ci setup, while a blower would be a 408ci setup.

Ill be using the 6.0L block ive got now, as its a used block so its been through its core shift, and i already own it haha. It will be line honed, cam bores will be line honed since cam incident, bore/hone, deck and hot tank, so it will be essentially a brand new block, i just wont have to worry about core shift.

 

Very true haha, wasnt thinkin of heat evaporation. good call

 

Twin setup is nice for packaging components. smaller turbos with 3" downpipes as compared to a large single 4" thats harder to snake through the engine bay depending on turbo location.

If you want 1000 whp start changing the thread to 8 second corner carving irocz. I went 9.8's on a LAZY launch with just 650whp haha, granted its through a loose converter so it may be closer to 700+whp with a tight converter. But 300 more whp is an 8 second car with decent launch.

Regardless, an 88mm should do it. I"ve seen mustangs with smaller cubes do over 1000whp with 76mm turbos.... A T4 based 88mm should do it but get the larger A/R so back pressure isnt as much of a concern. A T4 88 or 91 will spool pretty quick so I wouldnt call it unstreetable. Boost that comes on slower from a late spool would make it more streetable in my book but you wont have to worry about it.

I'd be happy with a 88mm that makes 800whp on this application. Just need to figure out where to put that big turbo. Tubular K member/a-arms will help things


Oh and why 370 with turbo and 408 with blower? Go 408 if you can in any blower/turbo application. And I thought MightMouse had a custom APS twin kit on his car that ran 8s?

 

From one of the threads i saw on ls1tech he was a single PT88, he's put the 91 on his car now and is one of the first guys to run it.

As fir a 370vs 408, few of the guys on LS1tech reccomended the smaller cubes for something like a PT88, though i wonder if the extra cubes would assist in it spooling quicker

 

Dave did some more on the drawing. Tips are PERFECT now, his drawing ability's are out of this world for only being 19.

 

Just need to look at the compressor maps.

I"ve seen 88's on 4.8L motors make over 700whp and i've seen alot on 408's that do very well. 88 Can work on larger cubes just need to match the rpms/desired pressure ratios to the compressor wheel and get the proper turbine a/r for spooling.

Just by some rough calcs, i'm guessing 22-23 psi on a decent 408 will do 1000whp assuming peak hp around 6K rpm. pressure ratio required is 2.7. On a garret GT47 88mm, thats in the operating map although pushing it a bit hard, its still doing ok.

A 370 would need few more psi, 25-26 and a PR of about 3 assuming same rpm peak. Still in the map but the more cubes you have, the less boost you need to run and i'm always a fan of that. Keeps it more pump gas friendly.

 

Definately agree with you there. Ill take a better look at teh compressor map's to see what cube's would be best with it.

I dont want it to be a racefuel motor, so if i can make more power with less boost, then thats perfect. It will run on 91octane with twin nozzle meth injection.

Id like to keep boost a bit down, as i dont really want to run a 6bolt block unless ive got to, so less boost will be less likely to push water

 

I've been up to 18psi on the dyno on 93 oct pump gas no problems, and thats about 700whp through a crappy loose converter. It should be more like 800 once its tuned and has proper converter

If you only have 91 you may need some meth. Small single nozzle should handle it. Larger cubes will make more power with same boost so build it big.

Another recent build on LS1tech was a blown 364" LS2, stock heads/intake and it made 834whp at 17psi with meth injection. A larger motor may make that on straight pump

 

Dr. Turbo on LS1tech has noted in a thread about the new PT88/91 that it is best situated for a sub 370cube build.

And went on to say that anything more then 370ci, and backpressure will go through the roof, and power level will go down.

I think im set on the PT88/91 turbo, it will support over 1000rwhp, its a T4 turbo, and will be fully spooled by 4000rpm.

Ill be running meth either way, im real comfortable with meth, and ive run it on every vette i built. Its a nice safety margin, it would be boost refrenced either way

http://www.ls1tech.com/forums/forced...ick-treat.html

That turbo seems to be money for what i want. I can run flipped truck manifolds, and its a T4 turbo so it will fit into the engine bay. Its about as much turbo as you can get into a T4 setup.

Beside the turbo, ive got to determine what heads to use to reach my power goals and will still hold the boost in the cylinders. I know the L92 heads are useless in boost situations, but if i can run a 317 casting head without much work to it other then springs that would be perfect.

As for intake on it, likely ill run a LS2, as i can run a 90mm tb. Id rather run a Vic JR with a elbow, but i dont want to change the hood, and i know that wont fit under it.

Havent thought too much about the transmission yet, but ill definately be running a Quicktime SFI bellhousing just incase theres a clutch problem.

Im hoping to start into some work on this soon, ill start the engine bay/rad support fabrications probably in a couple weeks. Ill be setting the rad further forward to clear the turbo, not sure on rad size yet.

 

I think its a good turbo choice i just dont think i agree on the back pressure issue when its used on a 364 or 370 or 408. Most high hp builds using 88mm+ turbos on motors like those should use a T6 anyway

 

Agree with you on the T6 flange. Im patiently waiting to see if someone on LS1tech uses a PT88 and 4xx cube motor to see their results.

 

I believe parish used that turbo on a 408 truck that made 1000whp+. My friend was going to copy his build but his 408 blew up so ended up using the 88mm on a 4.8 truck motor and made 708whp on it

 

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best of luck sheldon

 

Sheldon, good luck with the build. Remember less is more when it comes to race stuff. Keep it looking stock is always cooler.

Why do you say the l92 heads are "useless under boost"?

 

Thanks!!

Problem with L92 heads are they are a cheap casting, meaning the decks are thin. They wont go much past 14-15 psi before the thin decks show, and they will start pushing water.

They wont keep the boost in teh cylinders for the levels of boost i want to be hitting. Im hoping a 317 or 243 casting will, if not, ill step up to some trick flows or something with thicker decks.

I dont think my projected power levels will ever have me wanting a 6 bolt setup.

 

I know alot of guys have had good succes with 317's

 

I guess someone forgot to tell GM that these heads won't work on boosted engines.



LSX376—Ready for forced induction!

Boost on a budget! That's what you get with the LSX376. GM Performance Parts takes the LSX Bowtie standard-deck block, adds blower-friendly 9.0:1 forged pistons, and combines them with the LS3's high-flow heads to create an affordable foundation for supercharged and turbocharged combinations. There's no telling how much power you can realize once you swap it into a street rod or classic muscle car for a modern update!




That motor makes 450hp at 9:1 compression. If you put an 88mm on that motor with a nice sized inter cooler or meth injection and ran it up to 18psi you could make about 700 at the crank. Thats enough to go 9.90's. Those heads will handle 18psi with cometic head gaskets.

 

GM built that motor to be okay with the TVS series blowers, which are 13 psi pulley'd and 8-9psi regularily.

The castings are too thin of a deck to withstand high boost pressures, which results in pushing water.

At the 20+ psi i want to be running, the heads simply have to thin of a deck and will cause more problems then power gains. Simpler for me to run a different head with a thicker deck and not worry

 

14-15psi on a healthy lsx based motor will get the job done for 9's

 

This sounds like an exciting build. I'm also very interested in how you will get the exhaust tips to tuck up that high into the GFX. It's not just the floor pan that's in the way, it's the LCA mount that's right there.

 

Keep us posted on what your using for hot pipes. Thats my speed bump. I just can't go out and buy a bunch of lsx manifolds.