Performance modifications for the "mighty" 3.1

[Supreme Cutlass]

I've seen this topic pop up more and more, and I'd like to know what the best performance modification is, as I'm curious myself.

 

Here's some of the things I know of, from easiest to hardest, aside from an engine swap.

 

FFP dogbones for better launches

FFP UD pulley

Performance chip

CAI (cold air intake)

installing a tubo from a TGP or TSTE

TB injected Nitrous

Swap in a top end from the 3100

Exhaust work

Port and polish

valve job

Shave heads for increased compression

Cam upgrade

Piston upgrade

 

If anyone thinks of anything else/finds something I did wrong, just PM or post.

[gp90se]

FFP dogbones won't give ya any more power, and yes you can launch better, but I don't count polly motor mounts as performance.

 

you did forget cold air intake, performance motor rebuild with higher compression pistons, or stoking the motor.

[mfewtrail]

I've seen this topic pop up more and more, and I'd like to know what the best performance modification is, as I'm curious myself.

 

 

If you can source everything for a decent price, the biggest bang for your buck would definitely be this option:

 

installing a turbo from a TGP or TSTE

 

Night/Day difference in power. My NA 3.1 is probably right near 3 seconds slower in the 1/4 mile vs. my nearly stock TGP.

[dbtk2]

I'd say do:

 

Cam

P&P'ed 3x00 heads w/topend swap with iron head head gaskets (bump up compression .5:1)

FFP UD Pulley

TGP Turbo swap w/GT2871R (or better) turbo upgrade

29lb. injectors

 

Then it would run pretty well.

 

Shawn

[Supreme Cutlass]

Well, here's what I was thinking of doing with my car; Put on poly struts and a UD pulley now, then, Find an intake from a 3100 at a jy, port and polish them, get the valves done etc., that way I can still drive my car if I screw something up. Then put on the new intake. Do you think that would give me a big performance boost?

[Supreme Cutlass]

bump?

[dbtk2]

Well, here's what I was thinking of doing with my car; Put on poly struts and a UD pulley now, then, Find an intake from a 3100 at a jy, port and polish them, get the valves done etc., that way I can still drive my car if I screw something up. Then put on the new intake. Do you think that would give me a big performance boost?

 

That would provide a pretty good gain, should definately be noticable, however I would do a cam at the same time since you have to take the front cover off for the 3x00 swap anyways, so you pretty much have the whole job done anyways.

 

Shawn

[manitcor]

dollar for dollar, pound for pound you will never come close to what forced induction gives you, particularly when you use a turbocharger

 

http://www.donkeypunchperformance.com/store/index.php?main_page=product_info&cPath=67&products_id=202

 

On a stock 3100 (stock injectors, PCM, etc) at 4psi I dynoed 171hp and 218tq at the wheels.

[gp90se]

manitcor, I disagree. a 50 shot of nitrous will give the same results @ 1/4 the cost. Either 1 (turbo or juice) should have an aftermarket fuel pump, but a fogger kit can be picked up for $350, toss in a ricer filter for $20. Nitrous is also easyer to install, only used when needed which is easer on the engine and you can still use 87 octane when not racing.

[manitcor]

manitcor, I disagree. a 50 shot of nitrous will give the same results @ 1/4 the cost. Either 1 (turbo or juice) should have an aftermarket fuel pump, but a fogger kit can be picked up for $350, toss in a ricer filter for $20. Nitrous is also easyer to install, only used when needed which is easer on the engine and you can still use 87 octane when not racing.

 

 

depends on where you want your power, do you want to refill a bottle once a week (because realistly who will only use it at the track) or do you want the power anytime you put your foot down.

 

further you can run turbocharged systems on 87 octane, its all in how you desgin your kit and what your power goals are.

 

Ive yet to find a $350 fogger kit that I would even come close to considering safe to run on a stock car. Your always welcome to put in whatever you like but I wouldnt reccomend your typical off the shelf $300 universal fogger.

 

Also if you fill your bottle once a week ($5 per lb and a rather small 2.5lb bottle)

2.5lb bottle $650 per year

 

Meanwhile with a turbo there is power anytime the pedal is pushed down, and belive it or not fuel economy is excatly the same as NA as long as your not driving like Earnhart.

 

Unless you use your nitrous very sparingly a turbo over the long run will actually cost you less.

[gp90se]

I cant see 87 octane being used on a stock 3x00 motor with compression being over 10:1 under boost without detination.

 

I come across wet kids for $350 every once in a while that are plenty safe, most of them come with a WOT switch, but there cheap if not included.

 

A turbo car will get slightly lower mpg around town because it needs to run a little more rich.

 

I will be running juice on my 3.4 car when I get bored with it, but I don't plan on being trigger happy with it either.

[manitcor]

I cant see 87 octane being used on a stock 3x00 motor with compression being over 10:1 under boost without detination.

 

I come across wet kids for $350 every once in a while that are plenty safe, most of them come with a WOT switch, but there cheap if not included.

 

A turbo car will get slightly lower mpg around town because it needs to run a little more rich.

 

I will be running juice on my 3.4 car when I get bored with it, but I don't plan on being trigger happy with it either.

 

What 3x00 engine is running over 10:1?

 

3100 and 3400 stock run 9.6:1 and are tuned for 87 octane stock.

 

I have seen more than one 3x00 turbo kit, get the same gas mileage as before with no issues. Theres no need to run richer at idle or low rpm ranges as you are not creating any boost. The only reason you would run richer at all would be heat issues at idle however those can be mitigated with the correct design.

 

The 3x00 and DOHC engines have proven to be very resienlt to knock even on non-intercooled setups at 7psi. Now maybe its not possible with the older engine PCMs but the 97+ pcms give alot of control over timing and fuel to run things.

[gp90se]

With 4psi thru any 3x00 motor, compression will be 10:1 or higher, I worded that poorly.

 

After OBD1 I really don't know much about tuning, have not looking into it at all. will the computer automaticlly pull timing/add fuel for boost?

[manitcor]

Im confused, please explain to me through what magic I like to call physics does the amount of air pressure increase the compression ratio?

[gp90se]

you have more pressure in the cylinders under pressure, more pressure = more compression = more power = more chance for detination (sp)

 

DING

[manitcor]

funny I, last time I checked compression ratio was calculated from bore, stroke and the volume of the combustion chamber including gasket width. Compression ratio has nothing todo with how much air and fuel (ie mass) that you can push into that volume of space. Yes higher compression does give more power by increasing pressure in the chamber provided your stroke length does not change however its not quite the same as building boost.

 

Detonation happens either from heat or too much compression causing the air fuel charge to pre-,aturely detonate. Adding more fuel is used to cool things down and delay the explosion. Other ways (and better ways) are via intercooling or (some people) do a form of water in alchoal injection.

[Vegeta]

Static vs dynamic compression. You can run 12:1 on midgrade if tuned properly with headers. How does that figure out with 10:1....

[dbtk2]

I cant see 87 octane being used on a stock 3x00 motor with compression being over 10:1 under boost without detination.

 

I come across wet kids for $350 every once in a while that are plenty safe, most of them come with a WOT switch, but there cheap if not included.

 

A turbo car will get slightly lower mpg around town because it needs to run a little more rich.

 

I will be running juice on my 3.4 car when I get bored with it, but I don't plan on being trigger happy with it either.

 

I can run 8.5psi on 87 octane with no KR in my STE.

 

Shawn

[Supreme Cutlass]

Well, here's what I was thinking of doing with my car; Put on poly struts and a UD pulley now, then, Find an intake from a 3100 at a jy, port and polish them, get the valves done etc., that way I can still drive my car if I screw something up. Then put on the new intake. Do you think that would give me a big performance boost?

 

That would provide a pretty good gain, should definately be noticable, however I would do a cam at the same time since you have to take the front cover off for the 3x00 swap anyways, so you pretty much have the whole job done anyways.

 

Shawn

 

How to I go about choosing a good cam? what specs will show the most performance gains/ smooth or rough idle, etc.? And most importantly, are there any drawbacks to using one with a turbo?

[Supreme Cutlass]

bump