weird race

[Semifast4x4]

Ok heres the rundown truck A(me), truck B, and truck C.

we all got to a four lane up from my house to see how we each stack up, for those of you in the area old hwy 70.

the line up is

Left Lane

Truck A(ME)

1990 5.7 reg. cab, sb 4x4

intake

exhaust (no headers)

hypertech chip

8.8 wires

intake manifold

244 intake/264 exhaust cam

1.6 RR's

3.73s on 32x11.50x15's

 

Right Lane

Truck B

1999 5.3 reg. cab stepside 2wd WHIPPLECHARGED.

stock otherwise

 

Right Lane behind Truck B

2001-2 5.3 ext. cab, sb

intake

exhaust (no headers)

stock otherwise

 

Ok as soon as we take off From a dead stop me and truck B pull truck C by about a half truck length.

I stay door to door with truck B Supercharged  til about 50mph.

Hes' past me completely by 55 and is pulling hard.

By this time truck B comes past me like i was almost going backwards by 60-65 and i let off.

WTF Happened I can understand the supercharged truck but why would truck C just fly by me like that do those trucks just have a bad ass top end or does it sound like my truck needs something adjusted or tuned?

thanks for listening, and any help offered.

no bs flags i aint s*%ttin ya

[gandolphxx]

Interesting way to drag race - don't underestimate the LS1 5.3 engine, it is pretty strong from the factory.

[CMNTMXR81]

I smell Nitrous!  

[Semifast4x4]

So you guys are telling me pretty much that after all ive done to my truck a new intake and exhausted silverado will still just walk away from me:angry:?

Am i the only one that finds something wrong with that?

I understand I dont have a drag truck but ####.

and btw no nitrous i know both the guys I raced.

[RyanbabZ71]

Dont underestimate the power of the 5.3  

[CMNTMXR81]

While I agree with Ryan, from the way you described it, that's not the way the LS1 and it's derivatives act.  They don't just suddenly surge and explode past you.  They have a linear and strong power curve, so they should pull as smooth at 1,500rpm as it does near fuel cut off.  Anotherwords, no sudden surges in power.  The N/A 5.3, should've pulled at nearly the same "rate" as the supercharged 5.3, just not as fast/quickly.

 

With that said, the sudden surge that N/A 5.3 had, sounds to me like he flipped the switch to the giggle gas!

[MarkD]

Hey guys!  Maybe we are looking at this backwards.

 

It has been my experience that the early 90's V8's fell on their face at about 4000 rpm.  It might have been that the 5.3 didn't get a burst of speed of speed, the 5.7 just stopped pulling as hard.

 

It is all relative (rough Einstein paraphrase).

 

We used to have a 396 TBI motor that fell on its face above 3500 rpm.  At 3500, it had 450 ft. lbs of torque and 291 hp, but above 3500, the curve dropped at almost a 45 degree slant.  We changed the intake manifold and injectors, and gained a usable range of 2000-6500.

[Semifast4x4]

Mark D your answer sounds to me to be the correct one so I think I may have left out some crucial info for the nitrous boys  my 90 silvy is 4x4 on 32X11.50's, but i have the performer tbi intake manifold from edelbrock so if that helped your truck mark what do you think is still plugging mine at top end besides the fact my auto changes gears at 4500 tops?

[MarkD]

We went with a TPI setup from TPIS.  They call it the Mini-Ram II, 30 pound injectors, and a 52mm throtlebody.  

 

Will Autotap work on your truck?  Or do you need to use diacom to get the O2 readings?

[Semifast4x4]

Hey Mark D thanks for that i dea but

"AutoTap is an OBD II scan tool that works on 1996 and newer cars and light trucks." :angry:

Think you could point me to a few other manufacturers?

ANY help is Greatly Appreciated.

[SilveradoWV]

It could be that the truck that lined up behind the supercharged one was drafting!

[ByUBlue]

Semifast, if you still have the stock TBI on your truck, you are severely limited by the amount of air your truck takes in.

 

Even modified, your TBI can only flow about 520 CFM...not enough for you to keep up with a supercharged anything...well maybe a supercharged golf cart.

 

You need more air...then possibly more fuel. I have a 93 w/ 5.7 in it and when I took the ridges off my throttle body, and ported the top of the bores to let more air in, it made a noticable difference in top-end performance. Air is our friend.

 

If you really want to solve your problem, call Edelbrock about a MPFI setup. They have some sweet packages that will drop right on your truck and give you better gas mileage by 20%. Other than that, for less money, you can call TurboCity if you wnat a TBI that will perform as good as any without a total fuel system swap.

 

Our trucks have no top end compared to many other engines...not enough air. You can fix your fuel problem...but will still need more air than that TBI can suck.

[ByUBlue]

Where'd ya get those monster heads from?