Terry Houston 3"DP?

[UR50SLO]

How much luck have you had with your TTA Terry Houston DP?

When we did the conversion to our Camaro with the Buick motor I thought that the TTA DP would be a close fit with our combo.
I was mistaken. We had to cut it apart in several places to make it fit but it worked finaly.
We have a HD actuator on it so the .72mm turbo would be able to make 24-30lbs boost with out a bleeder valve.
We have run a best of 10.92@122 but could not make any more boost than 21lbs no matter how tight we made the actuator.

Yesterday I cut the DP apart and installed smooth pre-bent mild steel 90deg bends and 45deg bends out of 3 1/2 pipe from the start of the THDP all the way to our duel 3" system. So it go's from 3 1/2 right out of the turbo down to a splitter (Y) that makes the 3 1/2 duel 3" with two ultraflow mufflers and dumps just after the rear axel. All that was realy left from the THDP was the 1" thick flange that bolts to the turbo.

The we pulled out onto the street and had to do a double take on the boost gauge.. it was now reading 27LBS! We double checked the actuator.. it never moved! Just the back pressure from the THDP was stopping us from getting anymore boost than 21lbs!
Ours was not a "perfect out of the box" unit like the one's on your cars but I was wondering if anyone had put a different pipe on and gained anything like we did? Don't get me wrong Terry Houston makes a excellent quality unit and works with the space avalible with the TTA platform. We had to do extencive cutting and moving of unibody to make the 3 1/2 work. We reinforced it with 1/4 steel plate along with the cage and connectors I don't think we realy disturbed the structure. I'll take some pics and post them.
~Scott

 

[Roc87]

6 pounds difference??? Amazing..... I still don't know how you fit a 3" down pipe, much less 3.5" of down pipe. I was barely able to fit 2.5" pipe without hitting anything. But, with out the wg rod being tightened very far, I'm getting 19 pounds with the stock turbo. Will see what the PT51 does with a ported elbow this weekend (with alky).

Lets see some pics of that 3.5" downpipe!

 

[UR50SLO]

Did not sell the car then...?

You were trying to sell the car and then the motor/trans at one time right? I thought I spoke with you about the engine a few times... Glad to see that you have it in there! Cool! I'll take some pic's of it before we send it out to Jet to get coated. Like I stated it did take some unibody relocation to do it but it works

The car also came with a factory heater.. No A/C to work around so it's also a nice space adder.

Our first goal was to touch the 10's now we want to see the low 10's hopfully the stock stuff will hold up

We are getting 1.49 60's out of it maby with the larger down pipe and quicker spool we'll see the low 1.4's we are searching for with ET Streets... The 3:50 Gear helped out the RPM's at the end of the pass 5400rpm.The 3:89's were buzzing the motor at 6200!

We started the year off running 12.40's. Between Paul (owner) learning how to drive and me tuning the car we've come a long way in the last few months.

 

[Roc87]

Yes, finally got the swap done (Mostly). Nobody wanted to buy the engine/trans with the car so I stuck it out and actually completed it (Never again though, I should have just sold what I could and bought a TTA!)

A few years back when I had a 385 and a weiand blower I found a Berlinetta with out A/C and was lucky enough to get that heater box, but there is still little to no room for that down pipe.

Just bought a TTA rear, didn't figure having 25" tires and a 4.10 rear end would be good for anything but 1/8 mile!

I had some pictures somewhere, I'll see if I can find them and shoot them over to you....

 

[Razor]

Kinda weird..

The THDP for the TTA is way different than that of a GN..I also dunno if you were using a TTA THDP with GN heads..I dont see how you make an additional 6 lbs of boost by making it less restrictive..Boost is restriction.Leaving things the same if the restriction decreases..so does the boost..case in point is heads and cam.Just like if you put a banana in the tailpipe..the boost would skyrocket.

Maybe I'm wrong..but increasing the flow brings boost down.Not talking spoolup..not touching the turbo and increasing flow..brings boost down.Open a cutout and see.

I wont knock the performance..hell 10's is extremely stout for one of these motors..Congrats and I wish you well..

 

[UR50SLO]

I guess I don't understand how if you put a restriction in the exhaust that the boost would increase. When you have a restriction in the exhaust, Turbo or not your limiting engine output.
Some turbo systems just use a exhaust restriction for a boost limter! These are not high output engines but the application would be the same as the situation we had the Camaro in.
If boost would increase with a smaller down pipe everyone would be going smaller instead of bigger. "IF" you could change from a stock elbow and 2 1/2 down pipe to the 3 or 3.5 THDP with the actuator at the same setting (not using the stock controll unit) I'll bet you'd see a boost increase because the engine is flowing more air and allowing it to increase effecency.
Our case may be a little different because we have such a big compressor .72 with alot of Volume of air. We have such a open intake,intercooler,Air Cleaner,Heads that the exhaust was the restriction.. now with that open it can breathe.. Now we'll run into the restriction of Heads not being ported or blowing the bottom end up with too much cyl pressure/breakage of stock parts.
There's always going to be a weak link somewhere.

We put 3 full turns on the actuator before we changed the DP with no change in boost. When we did the new DP we gained 5-6lbs boost because it was restricing the volume of air being able to pass through it. It's all about getting the air in and out as fast as possible. Not that everything bigger is better just the right combo works good.
Thanks for your input.. ~Scott

86 Camaro body, Stock 87 GN block,crank,rods,headers, Steel ctr caps JE pistons, GN1 Heads (Unported) .72Turbo CAS-TTA-FMIC,
Perf.Trans 2004R 3500Stall, 9" Ford Rear w/3:50Gears,PowerConcepts,Inc. Rear susp,10ptcage,DP&Install.
See it herePower Concepts,Inc.

 

[Razor]

Hi Scott..thats why its great to be civil about things..

I can understand to generate boost the turbo has to be spun using exhuast gasses/pressure..and a restriction in the exhuast will not let the turbine spin as fast..

Pressure can be a tricky thing and probably not the same on any two cars.

My car runs higher boost with the cutout closed vs open..And I can see if the exhuast were to be restrictive..how boost could be compromised..I know of a local turbocharger company that uses pressure guages in the exhuast tract before and after turbo to map out wheels...Lot of work.

Again my opinion is running high boost isnt the answer..There are limits to the HG's for instance..and given the option of running 30 vs 25..I'll take 25 "if" I can make the same power as 30..heads,cam,IC,etc ..Now once the motor has been taken to that limit where the only thing left to do is boost...then and only then..go for it.

Anyone else ?

Julio

 

[UR50SLO]

I think your right on running the lower boost levels and making the engine more effecent. The smaller the turbo the more boost you'll have to run for a given CFM but you'll realy beat up the air doing it. I have chosen to run a larger turbo (for future engine plans Stage or the new TA Block) so we are not spending the $$ two times. The .72 is a little big for our combo but we don't have a spooling problem or a poor 60' (1.49)
I think we'll see a good mph change even at the same boost we were running before. Hopfully at 25-27lbs we can see some low 10s.
The last time at US 41 it was 55deg out with 21lbs boost I ran 29.5 degrees of timing with no knock.. is that strange??? 114oct fuel with 11.4 A/F ratio...
I think I'll knock down the timing to 24deg and run the 27lbs of boost and see what we get.

What timing and A/F ratio do you run.. Heads ect...? FAST system or stock? What timing on spool up?
Thanks!~Scott.

 

[Razor]

Ahh I'm one of those that believes ya can get more out of stock stuff than one can believe..

I run all factory stuff on mine..I kinda am on the fence as to future plans and mods to the car..I have a lot to learn still and am trying not to break stuff in the process.

My car is your typical original TTA with the regular mods..Nothing special..stock ecm,stock MAF,stock cam,TB,Intake,heads,...it for some reason now hates high timing irreguardless of octane.Thats my new problem to chase down..

I ran 11.74 this weekend in hot/humid Florida..It will go mid 11's before years end.And with better weather I believe 120 very possible.I had a 117.2 trap on a run with a 23 degree chip this sat...

Your in a league of your own when you cross into the 10sec land..information dries up quickly.As you probably already know.

As far as AF..i'm in the process of building a WB for this purpose..
I'm ,according to the dynojet I had it on,am running mid 11's for AF..which is a little rich..but safe

You'll always make more power on boost than timing..Bring the timing down,up the boost,then start adding in timing ..I like three runs before a change of any kind.Unless it runs so bad that a change is mandated

Good luck with the combo..keep us abreast of your results..I may decide to follow

 

[UR50SLO]

That's Movin!!!!

Your doing a great job with stock parts!
Although I'd like to come visit you for a week in about January or so to get some warm weather!
The TTA compression is around 9.5-1 about a point higher than the GN engine's because of the heads right?
I'm wondering if that's playing a part of your detonation?
I have not worked with a actual TTA yet. All our engines are GN motors... Can't find a TTA quite as easy..

I've had alot of luck tuning my wife's GN with a Direct scan.
Stock engine with 149,000miles. It runs low 12's with a few bolt on's turbo,injetors,street chip ect. I had quite a time getting it to run right after the stock MAF quit on me. The 3 1/2 MAF out of a gm 4.3L truck and the Ramchargers MAF translator/extender chip finaly solved that issue. It's back to running great again.

I wish I had more information on tuning you engine but I just don't have any experience with the TTA. There are just not enough around! I sure wish there were!!!!
The CAS front mount is a good fit with the F-Body and is a good size.. if you don't have that IC it would be a improvement over stock.
Talk to you soon,Scott~