In the neverending search for more HP, i decided to do some testing reg. intake runner lengths on my 2 liter. I ordered some ITB extensions from TWM directly, and the next day they were at my door. The fit wasnt so great "out of the box" but nothing thats mass produced really ever is.



I spent a little time working them over, and here's a shot of them about 3/4 of the way through.



I ordered 8 extensions, and stacked 2 on each runner for an additional length of 80mm (3.2"). While this may not seem like a ton, if youre familiar with "ram tuning" theory, you know this is substantial. Plus, because theyre stacked, i can remove them, 40mm at a time. Heres a visual aid to show you the diff. in length.



Anyway, i should be back on the dyno with my oft-ignored 2 liter in about a week or so, in which time i will update this thread. Thanks for lookin.

 

good luck with it man. looks pretty good. u should probably pick up some torque with the longer runners. nice job smooting them out btw.

 

in for results steve

 

whoa, u cleaned the inside pretty darn good!, on ur second pic, u cant really tell that thers an extention sumwer there, good work!

in for the results too!

 

in for results

 

I too am in for results.

So far, I am unhappy with my TWM's compared to my old AEBS manifold/65mm TB setup.

- Derek

 

Good idea. Pretty cool that its semi-adjustable for length as well. That may come in handy if ya want it a little shorter later on...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Combustion Contraption &raquo;</TD></TR><TR><TD CLASS="quote"></TD></TR></TABLE>
Will that even fit in your chassis? Very curious to see how the different lengths move the powerband and affect peak horsepower. It's good to see someone out there testing
If this does not do the trick it's time to try out the PerformerX

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by b19coupe &raquo;</TD></TR><TR><TD CLASS="quote">
If this does not do the trick it's time to try out the PerformerX </TD></TR></TABLE>

I'll either be switching to the Performer X or Victor X for my 89x85 build.

- Derek

 

im going straight to the performerx

 

ITB's on headstand FTW.

(in for results)

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by b19coupe &raquo;</TD></TR><TR><TD CLASS="quote">
Will that even fit in your chassis? </TD></TR></TABLE>

Yeah, i put it back in last night, and theres plenty of room. It looks like i could even stick one more 40mm extension on there, except id run into problems with cyl. 4's air horn hitting the prop. valve, and the trumpets just not having room to "breathe".

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Combustion Contraption &raquo;</TD></TR><TR><TD CLASS="quote">

Yeah, i put it back in last night, and theres plenty of room. It looks like i could even stick one more 40mm extension on there, except id run into problems with cyl. 4's air horn hitting the prop. valve, and the trumpets just not having room to "breathe".</TD></TR></TABLE>

thats the only difficult thing I could see off hand. The dyno will tell the rest but Im sure you will pull your usual magic tricks.

 

LOL, ask b19coupe, i seem to have run out of tricks to make these things work.

 

Relocate the prop valve and lines, cut a hole in the firewall, and fab up one vent for the AC that blows in front of the air horns. That way if you're losing by a hair you can turn the blower all the way up and it will be like an intercooler. I call this ITBizzleAChizzleRAMAIRizzleCOOLER(t)izzle.

 

in for the results as well, even on a half *** street tune with the stock stacks i'm pretty happy with it, if you gain a bit more over the regular stacks i'll try it out as well.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by b19coupe &raquo;</TD></TR><TR><TD CLASS="quote">
Will that even fit in your chassis? Very curious to see how the different lengths move the powerband and affect peak horsepower. It's good to see someone out there testing
If this does not do the trick it's time to try out the PerformerX </TD></TR></TABLE>

im gonna say that with the shortest setup u will have most power and the least amount of tq. then when u sart to increase the length of the stacks u will gradualy see ur power peak stay the same but start to move back in rpms and and then eventually starts to drop while at the same time ur tq will increase a great bit in the mid range and become flatter with the longer the stacks u go with. of course there is a limit to all this but going from the short stacks through all the extensions u plan to run u will see similar changes like what i said above.


mike

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Aquafina &raquo;</TD></TR><TR><TD CLASS="quote">Relocate the prop valve and lines, cut a hole in the firewall, and fab up one vent for the AC that blows in front of the air horns. That way if you're losing by a hair you can turn the blower all the way up and it will be like an intercooler. I call this ITBizzleAChizzleRAMAIRizzleCOOLER(t)izzle.</TD></TR></TABLE>

LOL. That's great.

 

in for dynoooo

 

Interesting.... In for results too.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Aquafina &raquo;</TD></TR><TR><TD CLASS="quote">Relocate the prop valve and lines, cut a hole in the firewall, and fab up one vent for the AC that blows in front of the air horns. That way if you're losing by a hair you can turn the blower all the way up and it will be like an intercooler. I call this ITBizzleAChizzleRAMAIRizzleCOOLER(t)izzle.</TD></TR></TABLE>


hahahahaaha .........

 

Back from the dyno, just havent gotten the graphs scanned yet. That will be tonite or tomorrow.

Anyway, conventional wisdom ruled. Running the extensions (3.2" longer) peak HP dropped by a staggering 15-18 hp. (Depending on which run you were looking at.) Bringing the throttles back to their original lengths brought the peak power right back to where it was last dyno session.

The only other change to the setup was the switch from a standard RAGE header to the big tube version. I was pretty convinced before that the restriction was partly in the exh. but switching from 1.4" primaries to 1.8" primaries didnt really seem to do much.

Anyway, the next test will be a Performer X vs. TWM shootout. I think the results will be "eye-opening". Thanks for looking, graphs up later.

 

Try more cam with the longer ITB setup. You might get back some or all or more of the lost peak.

Also have the ceiling lift up higher if you know what I mean.

Contraption Engineering

 

Im running the pro2's right now, and we moved them around a bit, but the curve didnt seem very responsive.

I tried the ceiling thing, but the guys at Churches werent really feelin it.

 

Well if you can't raise the ceiling, then drop the oil pan. It will be like a Castrol Syntec commercial. You'll be up 25whp for about 4 secs.