I am building something a little different. I am taking a 305 block (bored .030) and using the Powerhouse Stroker 335 engine kit. I will be using AFR's 190cc heads. I will be running about 9:1 compression. I will also be using a ported plenum, SLP siamesed runners, and TPIS Big Mouth intake. I think I will use something similar in specs to the TPIS ZZ9 cam possibly with larger LSA around 114 to 116 degrees. I will be using SLP's coated headers 1 3/4" running to Borla adjustable Catback exaust with no cat and the least restrictive plate on. As far a forced induction goes I will be running an ATI procharger (most likely P-1SC, possibly D-1SC) at about 18psi of boost at 6,000rpm and a 3 core intercooler. Other parts in the induction system will be utilizing the ram air setup I have now (if possible) to get the coolest air possible to the supercharger, ported mass air sensor (if I still need more flow, will switch to aftermarket or GM speed density, because on the procharger kits the mass air goes between the intercooler and the TB.), and a 58mm TB. Theoretically if you run 17psi of boost at 9:1 compression you will double your horsepower.
To make this setup streetable I will be using an Art Carr or TCI Street Fighter 700-R4 with a Gear Vendors Under/Overdrive strapped on. With the gear vendors I will have 8 effective forward ratios which helps keep your engine in its best powerband and it will give me an .55 8th gear ratio coupled with a 3.73 rear gear for decent highway manners and high top speed. Theoretically not using drag as a variable I could have a top speed of 225mph.
My objective with this project is to make a streetable car that will knock down good number on the strip, top speed, and mileage. Only time will tell if I can do it.


I didn't include this in my current profile but will be in future:

Top Speed 160 mph

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1986 Iroc Z 305
3.23 posi-rear
ported mass-air
custom ram-air
removed air pump, converter, straight pipe no muffler
0-60 5.5 sec
1/4 mile at 102mph
est 285hp
fiberglass hood
$2000 Alpine stereo hit 135 in spl comp.

 

One thing you might want to consider if you're on a tight budget is *not* stroking it. On a NA engine, its great for the extra cubes, but forced induction makes up for it quite well. Of all the stroker 350's (383's) I've seen, there was no significant hp gain from the midrange on up. If you're keeping the TPI/super-ram you should have plenty of torque at 2000 rpms, so the stroker might not be much of a benefit. Besides, the stroker puts a bit more stress on the piston and connecting rod as well (longer stroke in same amount of time = more acceleration forces on the piston/rods). Just my few cents, and a of contrarian opinion for good measure. It'll be unique, though!

A.

 

I completely agree. When I had my 305 rebuilt three years ago, I did inquire to Powerhouse about stroking it. I was told that I would NOT be able to rev as high as a non-stroked engine. I don't believe you will be able to come close to attaining 6,000 rpm with a stroker.



------------------
Willie

Supercharged 1987 305 IROC-Z, Daily-Driver, Emissions-Legal.
12.57 @ 111 mph.
12.04 @ 114 mph (50-hp nitrous).
http://members.optushome.com/au/downunder1/rides/willie/willie.html

1987 "20th Anniversary Commemorative Edition" Z28 Convertible -- Super Chevy Show Class Winner, 1998.

My custom front marker lamp assemblies:
http://members.optushome.com/au/downunder1/misc/lens.html

 

Thanks for the comments guys. Thats just the kind of advice I was looking for. Andris, its always good to have someone with a contrary opinion, it helps you see the whole picture, and I always like a challenge. Willie, I'll have to call Powerhouse and check on that stroker kit because it doesn't use longer rods (still uses 5.7") so it may not react the same. I would like to build a car that lives in Viper territory without any fear, and show those Viper owners what you can do for at least half the price. I am getting a new computer for Christmas and as soon as I get a scanner I'll post some pics of my car. I promise you will like it. As always I appreciate any advice.

------------------
1986 Iroc Z 305
3.23 posi-rear
ported mass-air
custom ram-air
removed air pump, converter, straight pipe no muffler
0-60 5.5 sec
1/4 mile at 102mph
top speed 160mph (racing a mustang)
est 285hp
fiberglass hood
$2000 Alpine stereo hit 135 in spl comp.

 

Thanks for the comments guys. Thats just the kind of advice I was looking for. Andris, its always good to have someone with a contrary opinion, it helps you see the whole picture, and I always like a challenge. Willie, I'll have to call Powerhouse and check on that stroker kit because it doesn't use longer rods (still uses 5.7") so it may not react the same. I would like to build a car that lives in Viper territory without any fear, and show those Viper owners what you can do for at least half the price. I am getting a new computer for Christmas and as soon as I get a scanner I'll post some pics of my car. I promise you will like it. As always I appreciate any advice.

------------------
1986 Iroc Z 305
3.23 posi-rear
ported mass-air
custom ram-air
removed air pump, converter, straight pipe no muffler
0-60 5.5 sec
1/4 mile at 102mph
top speed 160mph (racing a mustang)
est 285hp
fiberglass hood
$2000 Alpine stereo hit 135 in spl comp.

 

I contacted Powerhouse and they said that the only reason I wouldn't be able to run high rpms is because the stock heads with the stock bore wouldn't allow the engine to breathe. I am counteracting this problem by using AFR head with 1.94"/1.60" valves, I will also by using hydraulic roller lifters and AFR's hydra-rev kit to increase high rpm operation. Besides, the supercharger will also increase breathing. Andris, I saw on your website that you have a VE graph, do you have one since you put the turbos on, if so I would like to see it. I am trying to make this engine as efficient as possible. Everybody, please give me more comments.

------------------
1986 Iroc Z 305
3.23 posi-rear
ported mass-air
custom ram-air
removed air pump, converter, straight pipe no muffler
0-60 5.5 sec
1/4 mile at 102mph
top speed 160mph (racing a mustang)
est 285hp
fiberglass hood
$2000 Alpine stereo hit 135 in spl comp.

 

I'm not so sure I can agree to this:
One of my best buds has a stroked 400 displacing 434 cubes! Max hp occurs at 7400 RPM. He shifts at 7600 RPM. Its all in the airflow! You have to have the airflow to feed the inches. On a side note this was all naturally asperated. Last week he ordered a Procharger D2R + intercooler. He's changing cams (to blower specific grind) and Pistons (less compression). He's expecting 1200 Hp using 20 PSI.
Supercharging makes up some for not having as many cubes, but ultimatly more cubes will make more power all other things being equall.
Also I would avoid the TCI trans. I didn't and had it apart several times. The first time it was only in My car two weeks and blew a sprag. Then it blew other things (planitary gears+ring, etc. The last time it blew the entire input drum into about a dozen pieces. I then went to Art Carr and havn't had a problem since. The A.C. torque converter comes out of the hole better than the B&M Holeshot I had in the TCI too. They were both the same stall speed but the A.C. unit has better torque multiplucation.

------------------

• 355 cid
• AFR heads
• Arizona Speed & Marine hydraulic roller cam w/ AFR hydra-rev kit
• modified SLP runners
• TRW forged pistons/ceramic coated
• fully balanced
• Edelbrock headers/ceramic coated
• SLP cat-back
• Paxton supercharger
• Nitrous Express nitrous oxide

My IROC-Z
EFI Performance Club on Yahoo

 

Thanks for the comments. What you said about the stroker I believe is true. An engine is just a big air pump when you simplify it. It is obvious if you use stock heads and go up in displacement you won't be able to rev as high because you will choke the engine. That is what happened with the 350 tpi when they put the 305 intake on it, and that is also why they see such large performance gains when you put larger runners on it. Its simple a stroker engine will require more air than a stock stroke engine. Willie is putting 15psi boost on a 305, I want to put 18psi on a 335. His boost may show up sooner because of the restriction of the engine so even if I ran 15psi I would make more power because I would be flowing more air. More air+more fuel=more power. I am willing to estimate at least a 30% increase over Willie's 15psi. Like you said its all about airflow.
I have an update to my plan also. I have been referred by Grumpy in the Prom topic section to go with speed density for the amount of boost I want to run. He has steered me towards a Typhoon/Syclone ecm because it is designed to run with high boost. If anybody has any comments or has done anything similar to this please e-mail me or reply here. Thanks again IrocZ4me.

------------------
1986 Iroc Z 305
3.23 posi-rear
ported mass-air
custom ram-air
removed air pump, converter, straight pipe no muffler
0-60 5.5 sec
1/4 mile at 102mph
top speed 160mph (racing a mustang)
est 285hp
fiberglass hood
$2000 Alpine stereo hit 135 in spl comp.

 

Thanks for the comments. What you said about the stroker I believe is true. An engine is just a big air pump when you simplify it. It is obvious if you use stock heads and go up in displacement you won't be able to rev as high because you will choke the engine. That is what happened with the 350 tpi when they put the 305 intake on it, and that is also why they see such large performance gains when you put larger runners on it. Its simple a stroker engine will require more air than a stock stroke engine. Willie is putting 15psi boost on a 305, I want to put 18psi on a 335. His boost may show up sooner because of the restriction of the engine so even if I ran 15psi I would make more power because I would be flowing more air. More air+more fuel=more power. I am willing to estimate at least a 30% increase over Willie's 15psi. Like you said its all about airflow.
I have an update to my plan also. I have been referred by Grumpy in the Prom topic section to go with speed density for the amount of boost I want to run. He has steered me towards a Typhoon/Syclone ecm because it is designed to run with high boost. If anybody has any comments or has done anything similar to this please e-mail me or reply here. Thanks again IrocZ4me.

------------------
1986 Iroc Z 305
3.23 posi-rear
ported mass-air
custom ram-air
removed air pump, converter, straight pipe no muffler
0-60 5.5 sec
1/4 mile at 102mph
top speed 160mph (racing a mustang)
est 285hp
fiberglass hood
$2000 Alpine stereo hit 135 in spl comp.

 

Actually I am considering/researching the same ECM swap myself (165 to a 749). I am "coping" with my airflow now with a "more than usually" modified MAF to fool the ECM + big injectors, but when I swap the Paxton off my car in favor of a D1 Procharger I'll "overpower" my MAF "crutch". Maybe we can trade/share info & souces.

------------------

• 355 cid
• AFR heads
• Arizona Speed & Marine hydraulic roller cam w/ AFR hydra-rev kit
• modified SLP runners
• TRW forged pistons/ceramic coated
• fully balanced
• Edelbrock headers/ceramic coated
• SLP cat-back
• Paxton supercharger
• Nitrous Express nitrous oxide

My IROC-Z
EFI Performance Club on Yahoo

 

Thanks for your comments. That gives me a little confidence knowing that other people see things the way I do. Keep the comments coming.

------------------
1986 Iroc Z 305
3.23 posi-rear
ported mass-air
custom ram-air
removed air pump, converter, straight pipe no muffler
0-60 5.5 sec
1/4 mile at 102mph
top speed 160mph (racing a mustang)
est 285hp
fiberglass hood
$2000 Alpine stereo hit 135 in spl comp.

 

The maximum recommended compression ratio for a small block V8 with a supercharger is 8:1

Anything above that the supercharger's benefits are decreased.

------------------
1986 Camaro
Carbureted 305
700R4

 

Thanks for your comments. That gives me a little confidence knowing that other people see things the way I do. Keep the comments coming.

------------------
1986 Iroc Z 305
3.23 posi-rear
ported mass-air
custom ram-air
removed air pump, converter, straight pipe no muffler
0-60 5.5 sec
1/4 mile at 102mph
top speed 160mph (racing a mustang)
est 285hp
fiberglass hood
$2000 Alpine stereo hit 135 in spl comp.

 

That doesn't hold true in all applications, especially today. That was a good Idea 20 years ago when carbs, roots blowers, & mechanicaly advanced distributers were the norm. Electronic fuel injection, digital spark timing control, centrifigal supercharges, intercoolers,improved cam grinds, improved combustion chamber designs, etc. not to mention improved knowlege & blueprinting + assembly techniques, have changed the rules. The laws of physics are still the same we just have a better mastery of them now. If you did a survey I would bet you would discover that most supercharged EFI engines are running at or very near 9:1 compression.

------------------

• 355 cid
• AFR heads
• Arizona Speed & Marine hydraulic roller cam w/ AFR hydra-rev kit
• modified SLP runners
• TRW forged pistons/ceramic coated
• fully balanced
• Edelbrock headers/ceramic coated
• SLP cat-back
• Paxton supercharger
• Nitrous Express nitrous oxide

My IROC-Z
EFI Performance Club on Yahoo

[This message has been edited by IROCKZ4me (edited December 20, 2000).]

 

Thanks for the rebuttle IrocZ4me. All of what you say is true. If you request info on an ATI Procharger they will send you lots of paperwork. There is a chart on one of the sheets that shows how much boost you can run with a specific compression ratio. The max for 9:1 compression is 17 or 18psi. I consulted ATI about using aluminum heads and they said you can add about one more psi because of the heat dissapation. Also they have compression ratios on the chart that go all the way up to 11:1, you can't add much boost to that though. The future of supercharging is intercooling and ATI is at the forefront of this movement. Each ATI supercharger is designed to feed a 500ci engine. Do your homework before you question someone. A benifit to intercooling is also no timing retard on pump gas, depending on how efficient the intercooler is. If a supercharger company told you that 8:1 is the limit then their system is inferior. If that was the case then you couldn't run a supercharger on a stock engine. How many stock engines do you know of with 8:1 compression. Thanks for the comment anyway. I'd like to help other people learn along the way.

------------------
1986 Iroc Z 305
3.23 posi-rear
ported mass-air
custom ram-air
removed air pump, converter, straight pipe no muffler
0-60 5.5 sec
1/4 mile at 102mph
top speed 160mph (racing a mustang)
est 285hp
fiberglass hood
$2000 Alpine stereo hit 135 in spl comp.

 

I wouldn't go so far as to say "No Timing Retard if its IC'd" but rather say less timing retard. With the forced induction, the air is heated up when compressed (say 250 degrees at 20 psi) If your intercooler is 80% efficient, then you'll be back down to 106 degrees.

250deg boost - 70 deg ambient = 180 deg * 80% = 144 deg loss
250-144 = 106 degrees

Since you're adding twice as much air and fuel, the mixture in the combustion chamber is more dense and turbulent usually, giving a faster burn time, in addition to the extra heat from the hotter than NA pistons, etc (since about 1/3 of your total hp is given off in heat to the cooling system, the double hp = double heat, so hotter parts)... What was my point again? Oh yeah - you will still probably have less timing advance than running NA in order to prevent detonation.

The various high-tech ceramic coatings in the combustion chamber, on pistons and valves, etc, all keep the heat in the combustion chamber and try to limit the heatsoak to the components.

The best bet is to run the optimum timing and raise your octane instead so that you develop the most hp possible

If you guys are interested in learning more tech about engine design, benefits and drawbacks of longer or shorter rods, etc... you should harass your significant other, your relatives, etc to get the books about small block chevy engines by David Vizard. There is a ton of great info about why and how with the SBC, and goes into much more detail (as opposed to the Lingenfelter book which basically skims the surface...) I've rambled on enough. Back to work

Andris

 

Thanks for the tip Andris. I know it would be optimum to keep timing and add octane but thats kinda hard to do on the street. What you could do if you have a computer ignition is adjust the timing for when you run on the street, and then turn the timing up when you go to the strip. My project will mostly be driven on the street, so I quess before I get it out there I'll have to do a little experimentation. Keep the comments coming, I learn more and more every day.

------------------
1986 Iroc Z 305
3.23 posi-rear
ported mass-air
custom ram-air
removed air pump, converter, straight pipe no muffler
0-60 5.5 sec
1/4 mile at 102mph
top speed 160mph (racing a mustang)
est 285hp
fiberglass hood
$2000 Alpine stereo hit 135 in spl comp.

 

A pretty simple answer to variable timing for street/strip is to use a variable boost retard device like what is available from MSD or Jacobs. You can dial in the required retard for pump fuel then back it off when using race fuel.

------------------

Tracy /AKA IROCKZ4me

• 355 cid
• AFR heads
• Arizona Speed & Marine hydraulic roller cam w/ AFR hydra-rev kit
• modified SLP runners
• TRW forged pistons/ceramic coated
• fully balanced
• Edelbrock headers/ceramic coated
• SLP cat-back
• Paxton supercharger
• Nitrous Express nitrous oxide

My IROC-Z
EFI Performance Club on Yahoo