Performance expectations: "easy" upgrades

[Coelacanth]

I'm wondering what kind of performance estimates (1/4-mile) you might have for a 3.8L Turbo with what I'll call "easy" upgrades to the intake & exhaust; stock turbo, stock injectors, no alcohol injection, everything working well, with a recipe similar to this...

-Upgrade stock intake with 3.5" pipe from turbo to 3.5" LS1 MAF sensor, 3.5"-to-4" K & N cone filter;
-Downpipe upgraded to 3" unit
-Remove catalytic converter
-Upgraded Walbro fuel pump/hotwire kit

This would be phase 1 of what I'm planning; all of this is pretty easy bolt-on mods that simply improve the intake/exhaust flow; certainly nothing too ambitious and I wouldn't be expecting major performance gains, but I'd be interested to know your opinions on how that would perform compared to bone-stock.

Next phase would be a TT chip, bigger injectors, increasing boost on the stock turbo and probably sticking to premium pump gas; I'm not ready for alky injection yet. Looking forward to your thoughts on phase 1...thank you!

 

[1952ray]

You have NO choice but to use premium gas. Even that is not so good with the stock chip. Gas was way better back in the day

 

[Coelacanth]

True, gas was better in the past...I meant that to indicate I won't be driving around town with race gas or alcohol injection, as the TT chip I eventually decide on depends on what fuel I'm using, I think...but I'm more interested to get some ideas on how much simple mods like I mentioned above might improve performance (or not).

 

[Eazy-E]

http://www.gnttype.org/techarea/recipes/recipepage.html
these are a bit dated but you get the idea
do you have a adj fuel pressure regulator?? and why no alky?? it really is the icing on top of the cake on a street car!

 

[3.8L V-8 eater]

I would guess low 13's to possibly high 12's...I would consider the TT chip to be added to phase 1 though....That's a basic mod that will help idle and drivability as well as performance!!

 

[we4Mateo]

Pump gas will be your limiting factor. Mid to high 13s as you probably won't get past 100 to 104 mph in a full weight car. You'll need a turbo tweak or Bailey chip just to get a knock free tune on today's gas. What's the best unleaded octane available to you?

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[forcefed3.8's]

Mid 13's with good tires. The intake and downpipe will give 0 performance gain at that level. Add a test pipe and a Pypes Race Pro exhaust. With a TT chip, you will be able to run 17 maybe 18 psi. With the stock turbo, and especially on pump gas, the stock injectors are more than enough, no gain there. Put a 9 K&N cone filter on the end of the MAS and remove one screen from the MAS. A bigger turbo and injectors will do nothing at boost below 20 psi. Anything over 17 to 18 will require race gas, alky, or E85.

Now to show you how much of a restriction the factory heads are, I ran 12.2@107 on pump gas, 14psi with an NOS turbo with a non adjustable wastegate with a set of heads I ported. The car went 11.72@114 on race gas 20psi in 1st and 2nd, 18 by the top of third (out of turbo), 10.87@125 @22psi by changing to a TE63e turbo.

 

[TurboTnZ06]

Best I could do on today's pump gas in my old stock GN through stock intake, gutted cat, TT chip (tuned via scanmaster) was 13.0 at 104 in 40 degree weather with a tailwind and slicks. Usually it was 13.1-13.3 at 102-103 all day long. You'll only be able to run 16 psi boost, maybe 17 with a little KR here and there. Those times on my GN was consistent with my T when it was stock back in 2000 (low 13's at 100-104), actually better since I knew what I was doing this time.

Best bang for the buck is to get a TT chip, fuel pump, hotwired fuel pump kit, the kirban base plate for stock air filter, run alky injection and crank the boost to 24 psi.

 

[TurboTnZ06]

My best 1/4 trap speed on my T was on a stock MAF with stock MAF screen and stock intake tube... 130.8 mph... I say just port the stock elbow if anything. Leave cat, but gut it if it is not rusty.

 

[John Larkin]

I have no idea where you live but if E85 is available and somewhat accessible, go that route and don't look back. You can go faster for no more money than you are already planning to spend but your MPGs will suck. Its a good tradeoff.

 

[earlbrown]

Your phase 1 leaves a lot to be desired. Without valve springs it's going to fall on it's face.


Without a timing set it's doing to be dead on the road soon.

And without a good set of injectors (and modern chip) that aren't 1/4 century old, it's goign to help you shoot out a head gasket.



The preventative maintenance list is actually quite long.

 

[Coelacanth]

Thanks for the replies & suggestions. Earl, I have 2 cars I'm working on, and very limited budget. I do what I can with limited resources and a lot of my own elbow grease. Would that I could throw money at it without a care.

 

[coach]

I've always been different then most. I bought an all stock car and first upgrades were chassis and thats it. Adding horsepower to a "rickety bridge" didn't seem like a good investment. The car squeaks and rattles and is missing more body bushings then they actually installed.
My phase 1 was...
Boxing the trailing arms and new bushings.
bigger sway bar
Bilstein shocks
body bushings...including GNX bushings
front frame brace
front connecting bars
and the best $$$ was spent welding in the GNX rear seat brace.
The car felt like a completely different car and the tightness made it feel faster.

My Phase 2 was a downpipe and new exhaust
Scanmaster
Boost gauge
Hot wire and pump.
TT street 93 chip
valve springs
It was pretty good.

Phase 3 was a 49 turbo (27 psi) and ALKY...then the shit was flyin'...that was a fun 2 summers.

 

[1952ray]

Coach, did the same as you. Right on

 

[TT/Ameasap]

Dont forget locking the converter..... 2mph and .2 holds true.

 

[bison]

With open exhaust and drag radials high 12's on 93 octane with a decent driver. The car will be capable of 60' 1.65-1.7 with proper technique if youre 25 year old injectors are still good. 3" dp is a waste of $$$. I'd get rid of the stock intercooler restriction before I wasted $$$ on a dp. Way back when I had fuel pump @14v, m&h racemasters, 3" torque tech ex, Stock dp and intercooler and stock untouched longblock and the car went 12.40 with 110 octane 1.8 60'. On 94 octane it was a pooch. Maybe low 13's at best.

 

[bison]

Dont forget locking the converter..... 2mph and .2 holds true.

I've never seen .2 locking a stock converter. .08-.1 was normal. I have seen almost 3 mph though. The biggest reduction in e.t. Only occurs if it's locked at the correct time.

 

[TT/Ameasap]

I've never seen .2 locking a stock converter. .08-.1 was normal. I have seen almost 3 mph though. The biggest reduction in e.t. Only occurs if it's locked at the correct time.

Lock it before flight. Always worked for me and the Bradenton crew.

 

[bison]

Lock it before flight. Always worked for me and the Bradenton crew.

Locking immediately in 2nd netted me consistent 12.0-12.1. Locking in 3rd around 90-95mph with the stock turbo got me in the 11's. I made about 15 passes one Saturday back in the late 90's. Unlocked right around 12.1. Car was hot as hell every pass

 

[TT/Ameasap]

I think were splitting hairs, but I and others on this board have gained 2mph and .2 in the 1/4 with locking the converter.