My setup has been holding together great, this is the second season with the turbo setup and no problems what so ever, besides traction!
I was signed up for the dyno up at Powercruise in Brainerd, MN but the next morning rained like crazy so it never happened. A friend informed me last Saturday that a place 5 minutes from my house was having an open house with $25 dyno pulls and free food so I flew up there right away. My A/F was pretty rich, since I was still messing with main air bleeds to continue my cruise tuning. I typically like to run my A/F at WOT in the upper 11's, but that day it was at 11.1-11.2. This was running 9 psi which is what my track times last year were from. I now have an MSD 6AL2 box which has been awesome since I can run 34 degrees timing until boost comes up and then I had it dropping down to a total of 20 at 9psi. I could be a little more aggressive with it butI'm sure but the cast pistons are happy with it at 20.
So here's the graph. I'm guessing what it made that day wouldn't be enough to trap 123mph, but I'm not sure. I was expecting power to be somewhere in the 400's to make that kind of trap speed. See how the curve drops off a lot after 4700? It should be pulling strong to the mid 5000's I would think, since that's what it did N/A with just a little larger cam. Dyno guy there commented that the rich A/F might cause the high rpm fall-off. It was also interesting that their dyno's wideband read less than 10.3 A/F the whole time under boost while my LC-1 read 11.1.

Current cam is 212/222 @ .050 in a 350 with vortec heads, performer rpm, Holset H2E turbo.
What do you guys think?

 

I wouldnt be too concerned. Dynos dont load turbo cars well and they may not show true hp. They all read different.

Turbo side and exhaust side may make power peak sooner due to backpressure or other restrictions. So it may fall off sooner because of that or alittle bit of the tune factor but car seems strong at 9 psi. 123mph dont lie. Powerband seems right to me for 212 deg cam on vortecs

My 3450 lb car went 119 on 400 whp.

Dyno will not load motor as hard so explains why air fuel was richer. I noticed my car picks up a ton with air fuel lean outs if too rich. My 10 psi tune starting out went 134 at 11.0 air fuel. I went to 11.5-11.7 and went 137. Added a deg timing and saw 138.

Dont tune on the dyno, you can for bragging numbers but dont race it on that dyno tune. It will likely lean out too much

 

Thanks for the reply Orr. It's cool to hear what you've experienced as far as how A/F affects power. I've been curious of that since you can't really tell by the butt dyno what different A/F ratios and slight timing changes make on power. If the powerband is actually like that with a leaner and more aggressive tune than I've been shifting too late at 6,000. Anyways, not a big deal. It's cool that you know what you ran both on the dyno and at the track. I still need to weigh my car!
I wonder about the accuracy of my wideband vs the dyno's. My LC-1 on my car and my LM-2 on my friends car both read at least 1 point leaner than the dyno. 1 point is a lot to be off when you are relying on it for tuning.

 

i agree with orr, dont get discurraged with dyno numbers. They mean nothing more than a number. The general manager at my dealer has a highly modified 2012 cts-v that put down 780rwhp. He went 10.6 @ 132mph. My old rat, TPI car went 10.7 and 130mph before. The best numbers are track numbers, not dyno numbers

 

Try on a Mustang dyno, numbers are usually more realistic. On a Mustang dyno the operator can input car model, weight and I am not 100% but it also calculates air drag depending on the vehicle. The dyno will also calculate 1/4 passes, very usefull tool. All the fast GTR's here use them and this guys mean business, they are all into 1/2 mile races and serious drag racing.

 

If you could verify with a spark plug reading that would be helpful but its kind of a pain to do. Need to shut down after making a wot pull and look at one of the plugs. Sucks because you need to do a pull, coast down to a stop somewhere and pull a plug on a hot motor and likely complicated turbo setup lol not easy but beneficial. Or do it on a dyno

 

I think your numbers are right for what you have and the boost your running.
I would recommend getting rid of the turbo and carb.

As far as dyno not loading turbo cars properly , I had no problem making 200hp more with 74ci less and 2 cylinder less on a dynojet.

 

Its not that you cant make numbers on the dynojets. Just saying you may have issues getting turbo motors to load up and make full boost and full power on your optimized track tune, when running it on a dynojet. My track and street tune saw 14 psi and mid 11's air fuel. I threw car on mustang dyno and still couldnt load it up. Only saw 12 psi and 10.9-11.1 air fuels. I made 2 street pulls to verify i was seeing 14 psi before getting on dyno


So just be aware of your tune on the dyno and leave it richer before track testing

 

Yeah I hear ya, thanks for the advice. I made it to the track a few days ago for the first time all year and was definitely slower than last year.

This year - only saw about 7-8 psi vs 9 on the street, AFR around 11.8-12 and timing should be around 24 at that boost. Best of 12.4 @ 116 on street tires. 2.3 60' (I haven't got the 9" installed yet) It was about 88 and humid which I'm sure didn't help!

Last year- same boost, 11.6 AFR and open exhaust 12.0 @ 119 on same street tires

The only real difference is I now have full length single 4" exhaust with a muffler vs just a 3 foot long down pipe out the side. My tune is pretty similar, although my timing might be a little more conservative than last year.

 

Are you saying run EFI with the turbo or get rid of the turbo too? lol

As far as my carb is concerned, I've got it working very well. Excellent driveability, consistent WOT AFR, good part throttle AFR and have even had a couple tanks of gas average over 18mpg. I'm always tweaking it a little here and there, but sometimes that's the fun part!

 

probably the carb.

i think the strange low rpm peak of your setup is the heads and maybe a little bit of the cam. a touch more duration and a lil more LSA would move the rpm up ~200-500 rpm

the LC1 is inaccurate junk. be careful trusting it.

back pressure COULD be an issue. what turbo are you using and what size dp?

 

I was talking about the holset. You might want to talk to Turbonetics or Percision turbo. Yes get EFI it's way better than the obsolete carb.

 

I'm thinking the low rpm HP peak might be due to my tune and maybe the backpressure between the heads and turbo required to make boost with more restriction in the exhaust after the turbo. My downpipe is 4" mandrel bent from turbo to rear bumper with a big flowmaster muffler in the rear. Maybe the muffler has sucky flow. It'd be interesting to remove just the muffler and see what effect it has.
It's interesting my HP peak back when I was NA was around 5500 rpm, so something is definitely affecting it. Last year when I trapped 123 at 10psi it felt like it pulled hard to almost 6000rpm but that would be hard determine without a dyno I guess.

 

a T70 would do quite well with his setup..

 

Agreed. I don't recall the Holset H2E compressor wheel size, but I think it's in the 63mm range. It's a smallish turbo, matched with a carb and Edelbrock Performer dual plane intake setup at a mere 9-psi of boost. Be happy with the power you made. I would go with a slightly larger Precision turbo, but with a single plane manifold instead of the dual plane if your that content with the carb...

 

if it's a chambered flowmaster try yanking it for a session and seeing what happens.

 

Well I made a great discovery the other day! Checked my timing just for kicks and my base timing somehow moved about 7 degrees retarded from where I thought it was! With the MSD 6AL-2 box I have, I have the base timing set at 45 and pull timing from there. When I checked it with 0 degrees advance it was only at about 38, big difference! That put my max timing at 8 psi at around 18 instead of 25. Plus I had my curve setup to actually pull a few more degrees after 5000 ramping to 6000. Not really sure why I did that, but I changed it so the rpm graph is steady from 2400 to redline. So now my timing is this: "mechanical advance" ramps up from about 20* at idle, all in by 2400 at 34, steady to redline. Boost/vac curve starts to pull timing out from 45 (base) at around 12" of vacuum, dropping down to make my timing at WOT at 0 psi 34*, then pulls more timing starting at 3 psi, pulling it down to a max of 28 at 6psi, 25 at 8 psi, and 23 at 9-10 psi. Light throttle cruising it is barely pulling any timing from my base of 45, so it runs between 40-45* cruising. Last tank with only punching it a few times net me 19 mpg! If that makes any sense to you guys, maybe I lost you, oh well.
Bottom line is it is WAY faster now that it's back running 24* timing at 8psi instead of 18*. So that would explain my dyno and slower trap speeds. I don't think the full exhaust is hurting it anymore.
My car is running the best it ever has right now, idles perfect at 700rpm, great response, runs in the 14.5-15.2 A/F cruising, 12-13's under light to medium throttle, and locks itself at 11.7 at WOT. The worst milage I've ever gotten is around 12, best of 21mpg. Loving it! Who says blow thru carbs suck? Only 2 years of constant tuning and a entire notebook full of notes, I guess that's all it takes!
Also with the more aggressive timing pre-boost it spools great, I don't think I could improve that much by switching turbos. I'd love to get back on the dyno now and see what it does. Plans for this winter are installing my Moser 9", new driveshaft, and torque arm. I'm guessing next year I will be too quick without a roll bar, so that'll probably be next after that.

 

Congrats, its always something with these cars when numbers dont look right. Bet it picks up a ton on the dyno. Timing makes a huge difference with boost

 

The only real difference is I now have full length single 4" exhaust with a muffler vs just a 3 foot long down pipe out the side. My tune is pretty similar, although my timing might be a little more conservative than last year.[/quote]
I'm no dyno guy but here's some interesting facts. I do a lot of custom work for a Mustang Dyno guy and also a lot or work for several restoration & street rod businesses. I had a customer I did a polished cooling system for on a Dodge Challenger. Car had one of those 500 inch Indy all aluminum hemi engines in it. Engine dyno numbers were around 600hp. Once in the car, ran great but only pulled about 380 RWHP!!! Where did it go??? some obvious parasitic losses in drivetrain and automatic trans but not that much. Any way, I introduced my street rod customer to my dyno customer and here's what came up. Unhooked the exhaust from the headers and RWHP went up to 525! Reattached exhaust and back down to 380. I looked at the exhaust system. It was beautiful polished stainless steel dual 3" from collectors back. Only 3 bends per side. Tightest bends were the over the axle bends and looked about 35-40 degrees, other two bends about 15-20 degrees. Bends were D.O.M. bends with no sway in the pipe. All TIG welded. One muffler on each side clear at the back behind the axles and were straight through Magnaflow mufflers. Whole system looked very unrestricted. Hmmmmm. Never would have believed any of this if I hadn't seen it for myself. Conclusion is that if you are making much more than 400 flywheel hp exhaust needs to be pretty large or it will cost you.
Next episode...... My car has 414 dart, F.I. 14lb boost, E85, etc.... I built my own exhaust using Hooker Super Comps. The collectors are modified to go 90 degrees out each side with very short 3" D.O.M. bends. They transition into 4" side pipes with no inserts. Car made 782 rwhp. Diablo motorsports tech was at my dyno session and said I was probably losing 100hp at those 2 bends???? WOW! Would have never believed that either until the experience with the Challenger. I just put 3" electric dumps on in addition to the side pipes so I will post back after results here in a couple of weeks. Will be interesting to see what changes. Point being, you may be losing more power than you think with 2 into one 4" pipe all the way out. Take the 4" loose and see if your power comes back. Might be very surprised and may want to look into a 4" dump at the "y"??

 

Not sure if you read my last post, but I am no longer pointing fingers at the exhaust. Thanks for sharing your experiences though. That's pretty surprising.

 

I read your last post. Might want to consider an exhaust dump for the track though.

 

Well I made another discovery today. I tore all of my exhaust out of the car including the turbo to check things out and get it all ceramic coated. One of my flex joints between the engine and turbo had mushroomed out inside and brought the inside diameter down to just over an inch. I knew about the flex mesh coming apart on turbo applications but I didn't find that out until after I had built my setup. The other flex joint coming from the other head was already missing and must have made it's way through the turbine at some point. The turbo looks mint still, so I'm lucky there. I cut apart my pipe and removed the other internal mesh. I would say that would affect performance necking half of the engine down to a 1.25" restriction. We'll see how it works out soon once I get everything coated and back together.

 

Yup that will do it. Had that happen to my friends car. If you need a flex coupler then try one that has a liner inside, like the treadstone performance pre turbo flex couplers

 

Wow....now there's some choking goin on there! That's gotta hurt performance! Change that thing out with something that will hold up, and put it on that same dyno....bet it'll pull past 5K now!

 

Yeah, I'm glad I finally got around to pulling it all apart to inspect everything. I've been meaning to do it for quite a while. I managed to remove all the mesh so there shouldn't be anymore of that getting in the way. Two of my friends are running the same flex joints and discovered you can remove the internal mesh in about 30 seconds by prying the layer out before welding them in. I just dropped everything off to get ceramic coated today, hoping to have it back together soon and I'm expecting a little bit of an improvement. Haha. How the other chunk of mesh made it through the turbo without harming it is beyond me.

 

Confuzed1 - How is your True Trac holding up in your 9"? And how do you like your UMI torque arm? Is it cross member mounted?

 

The Tru-Trac has been fine...I've had it for at least 4-5 years now. It's as quiet as the stock 10 bolt actually....just a bunch heavier and bigger. The UMI torque arm I have is actually the cheaper non-adjustable.

The UMI guy that used to frequent here on the board tried to tell me that I needed an adjustable with this 9" Moser, or else the pinion angle would be wrong...but I've checked it and it's fine...right in spec. I recently put it on a Founders (I think) crossmember mount. Works great....pinion angle is still fine.