Headers and Exhaust advice

Hugemoose · #1 (**permalink**) 12-05-2005, 09:58 PM

First of all, just to let you all know, in case anybody is looking for a VERY good set of headers, for VERY cheap go to http://www.ssautochrome.com/
they have got headers an a y-pipe for $275. The headers alone at $175. They are direct bolt on shorties. I've got just the headers on and they are great.

They are made from stainless steel and have held up fine to all of my abuse. *You can also look on e-bay for them, something along the lines of Tundra Headers*

The other thing is I need some advice. Right now I've got a true duel 2.5" piping with an x-pipe and two flowmaster mufflers. I love the sound, but I do notice that my low end torque really sucks. I've raced my truck before at the track, and I seem to get around a 2.4 60 foot time. That was when i ran my best time of 16.16 sec at 85.67 mph. I new to this forum, and i've been reading a lot about how i should keep the y-pipe and put a 3 inch muffler on it. Here's my delima. I don't have much money, but I would love to redo my exhaust to get some of my low end torque back! The web site above has a nice looking y-pipe, but I could also re-use my stocker. I kinda want to keep the rest of the ehaust back simply because it would cost so much to buy a new muffler and re-fit the pipes. Any suggestions? Should I look into putting a y-pipe on, is it really worth it?

Thanks for any advice.

KLS · #2 (**permalink**) 12-06-2005, 11:56 AM

2" pipes would help your situation, as would the addition of an x-pipe crossover and scrap the true duals.

I've seen no benefit from an aftermarket y-pipe. You could bolt the original piping back on with one of your mufflers and be better off than you are now.

Ken

Hugemoose · #3 (**permalink**) 12-06-2005, 02:22 PM

Thanks for the advice. I'm thinking then i'll just take it to the shop where I got it put on and have my stock y-pipe put back on, then maybe one muffler and have the tip point down. My only question is, how far back must it be to be legal? I've heard a lot of guys talk about it, but does it need to be past the cab?

Thanks a lot,
David

TrueDuel · #4 (**permalink**) 12-12-2005, 05:26 PM

I think you were on the right track with the dual exhaust but may have been misguided in the approach. Base on the engine size and horsepower capacity of the 4.7 V8, 2.5" Is fine from the muffler back and 2" between header and muffler may be a bit small especially if you have other engine performance upgrades. If your X-pipe is back where the stock Y comes together You probably arent getting much benefit as it is not equally spaced from each engine bank making equalization difficult.

My approach was to bore the stock collector flanges to 2.25". Using mandrel bends I mounted 2 1/4" Dynamax Super cats and re-used Oxygen bungs from Stock cats. All positioned as close to factory as possible. That is followed by an 2 1/4" H-pipe under rear of trans. To position the mufflers correctly can be done with some masking tape. prior to mounting mufflers run temporary pipes about 2/3 back to the rearend. somwhere after the cats run tape down the legth of each pipe. Start the motor and let it run long enough to get the pipes good and hot. where the tape stops melting or burning is the best place to put the muffler. This improves flow as you are not pushing all those hot gasses through the muffler. On the tundra, keep in mind that the mufflers will probably be offset due to differences in pipe length or distance from the header collector. Two offset Center-side-Dynamax ultraflows fit perfectly on edge as the offset makes up for that S pipe that was on the stock exhaust. Mufflers are then piped back to the old 2.5" cat-back tail pipes and connected with three bolt flanges. It works great, no ill effect on 02 sensors. The H pipe creates a wonderfully balanced system. The HP and torque increase of this combination is incredible And gas mileage is better than ever.

Steve Z
2001 Tundra 4.7
Modified K & N intake, Helix Power Tower
S&S Chrome Stainless headers, Custom dual exhaust,
ARB Lockers,

KLS · #5 (**permalink**) 12-12-2005, 06:31 PM

The problem with dual exhaust is that all the V-8 engines fire with a firing order like this:
left
right
left
right
left
left
right
right

The lefts and rights might be reversed for some engines, but they will still have two pulses in immediate sequence from one side, then from the other. This causes congestion in the exhaust piping. The X-pipe relieves this. An H-pipe is better than duals, but not as helpful as the X-pipe. The only real advantage of duals is for smaller diameter mufflers for cars with reduced ground clearance. A properly sized single muffler and exhaust works as well at lower cost.

Bigger piping is not better. The bigger piping allows the gases to expand and cool. The sound pressure waves in the piping move at the speed of sound which is temerature dependent. Piping too small causes a pressure increase, and piping to big causes slowing of the scavenging and a pressure increase (back pressure is always bad--proper scavenging causes a negative pressure at the exhaust port when the exhaust valve opens). Piping just the right size for engine size and speed is needed for best power.

Ken

Hugemoose · #6 (**permalink**) 12-13-2005, 01:06 AM

I'll try to get some picutures on here soon so you all know what i'm dealing with here. I'm still in school right now, but it's finals week, yippy! So after this week i'll be home and i'll get some pics. I love the sound of my exhaust, but the low end blows! Top end is awesome, with the K&N and headers and exhaust, it really screams, I just miss some of the low end torque. I was getting beat by a 6 cyl. 5 spd. 90 something chevy 1500, needless to say I was getting scared cause he beat be off the line, and kept going, until I got up in the RPM's and FINALLY passed him.

Thanks for all of the advice, this is giving me lots of good ideas on what to do.

TrueDuel · #7 (**permalink**) 12-13-2005, 11:31 AM

If it's low end torque you want, add a Helix Power Tower. Low end torque is incredible. Once installed You will start to see other performance upgrade needs like Posi lockers or LSD if you dont already have either. If you tow anything you will be especially hjappy with this addition to your engine

SteveZ

01 tundra
headers
2 1/4" true duals with
Dynamax supercats
H-Pipe, Dynamax Uni flows
Modified K&N Intake
Helix Power Tower

dyogim · #8 (**permalink**) 12-13-2005, 11:48 AM

Quote:

Originally Posted by TrueDuel

If it's low end torque you want, add a Helix Power Tower. Low end torque is incredible.

For some reason, after testomonials from many TS members on these so called performance enhancing throttle body spacers, I highly doubt there are any gains from them. I can see some gains from your other mods but, not from the spacer itself.

Hugemoose · #9 (**permalink**) 12-13-2005, 03:17 PM

Quote:

Originally Posted by dyogim

For some reason, after testomonials from many TS members on these so called performance enhancing throttle body spacers, I highly doubt there are any gains from them. I can see some gains from your other mods but, not from the spacer itself.

Well I have heard some good things about throttle body spacers, mainly from older cars with carbs, but the basic princible is the same. When there is more volume in the air plentum (sp.) it equals more low end torque. The whole deal with the threads that are supposed to make the air into a "vortex", i don't really buy, but i do think it would help slightly.

My only issue would be that I have a K&N right now, and it is about a quarter of an inch away from the fan shroud, so there really isn't any extra room for it unless I start cutting away at the fan shroud and the fan itself.

TrueDuel · #10 (**permalink**) 12-16-2005, 12:32 PM

The reviews you read? You think I am making this up? I have been involved in hot rod and Street performance stuff since before high school, about 40 years, On the Tundra, I started with a cat back exhaust then added cold air intake. A marked improvement. The TBS was added and blew me away with the increase in low end torque and overall power.and still it felt somewhat choked or held back. I went to true dual exhaust with H pipe for a vast improvement. I don't know the stats on all throttle body spacers. Helix is a clone of the Jet spacer with some marked improvements. As far as the K & N intake with a TBS, Custom Fabrication is the key phrase. You will need to customize the K&N to compensate for the thickness of the TBS.

dyogim · #11 (**permalink**) 12-16-2005, 01:02 PM

Quote:

Originally Posted by TrueDuel

The reviews you read? You think I am making this up? I have been involved in hot rod and Street performance stuff since before high school, about 40 years, On the Tundra, I started with a cat back exhaust then added cold air intake. A marked improvement. The TBS was added and blew me away with the increase in low end torque and overall power.and still it felt somewhat choked or held back. I went to true dual exhaust with H pipe for a vast improvement. I don't know the stats on all throttle body spacers. Helix is a clone of the Jet spacer with some marked improvements. As far as the K & N intake with a TBS, Custom Fabrication is the key phrase. You will need to customize the K&N to compensate for the thickness of the TBS.

I'm not doubting you just the spacer. If the spacer actually provided more gain, more power to you. When I added my AEM intake, the only noticeable difference was an increase in sound coming from the engine bay. Same thing with my JBA catback EVOL exhaust. If I hadn't won the intake, I would've just stuck with my stock box and a drop in filter. I have definitely noticed a gain from regearing from stock 3.9's to 4.88's.

KLS · #12 (**permalink**) 12-17-2005, 05:05 PM

Quote:

Originally Posted by TrueDuel

The reviews you read? You think I am making this up? I have been involved in hot rod and Street performance stuff since before high school, about 40 years, On the Tundra, I started with a cat back exhaust then added cold air intake. A marked improvement. The TBS was added and blew me away with the increase in low end torque and overall power.and still it felt somewhat choked or held back. I went to true dual exhaust with H pipe for a vast improvement. I don't know the stats on all throttle body spacers. Helix is a clone of the Jet spacer with some marked improvements. As far as the K & N intake with a TBS, Custom Fabrication is the key phrase. You will need to customize the K&N to compensate for the thickness of the TBS.

Our trucks came stock with a cold air intake. If any of the other changes you've made didn't make more noise (intake & exhaust) or allow more dirt to enter the engine (K&N filter element), Toyota would have built them in. You like the throttle body spacer and nobody else does. I wonder why all the vehicle makers didn't just manufacture the engines with the correct throttle body spacing...doesn't increase noise, doesn't increase emissions, power for free...why not???

Ken