Bigger turbo, slower truck?

[absintheisfun]

So I got the Stage one RPM turbo and installed it....after all my (and Aj's and Darren's) frustration, I took it to a mechanic who owns/races and builds SyTy's close by to give it the final tune.
Here is the list of items that went on:
Turbo - 50 trim, T04E
A2A w HKS BOV
Walbro fuel pump
3bar map
Fuel pressure regulator
AEM boost controller & Gauge
Programmed Chip (piggyback)
(i might be missing something)

It runs like a dream and sounds vicious as hell, but it feels slower!
Everything is set exactly right, but it just doesn't feel fast!

A buddy took a ride with me and filmed it. A boost launch took almost 8 seconds to reach 60mph! WTF?????:tdown:

It put me back in my seat when I took off but what the hell?!?!?!?!?!?!!!!????

I only dicked around for a few minutes and did very few launches, but something isn't right. Any ideas?

Either my speedometer is WAY off, or something just aint right.

I was told that I did not need bigger injectors or a bigger stall converter for it to run right...

 

[SY2455]

Re: Bigger turbo, slower truck?

You don't list what chip you have. If you are still using the stock chip, then you don't need a 3 bar map. Is you waste gate adjusted right?

 

[absintheisfun]

Re: Bigger turbo, slower truck?

You don't list what chip you have. If you are still using the stock chip, then you don't need a 3 bar map. Is you waste gate adjusted right?

Piggybacked programmed chip...sorry, fixed.

Waste Gate is adjusted correctly 14.7lbs of boost

 

[JSM]

Re: Bigger turbo, slower truck?

I would still question the tune, I can make a tune that drives smooth and nice but will be slow.

Who is it that tuned it, if they race/own syty's we would probably know who I would think?

 

[absintheisfun]

Re: Bigger turbo, slower truck?

I would still question the tune, I can make a tune that drives smooth and nice but will be slow.

Who is it that tuned it, if they race/own syty's we would probably know who I would think?

Joe @ Mac's Performance in Ft. Worth, TX

I'm no expert, but he seems to be on top of his game.

 

[Goshinki]

Re: Bigger turbo, slower truck?

The Canadians told me I would have a slower spool time if I didn't get a bigger torque converter.

Don't know if it would make you that slow >.>

I have a 20g turbo and a 2600 stall converter (Its just my daily)

 

[It's just a six]

Re: Bigger turbo, slower truck?

It's probably retarding the timing.

What gas, methanol injection? Looking @ Knock retard? What psi? A/R on thurbine housing?

So this guy tuned the factory ECU?
He used a lap top?

Need more info.

 

[jpalmer]

Re: Bigger turbo, slower truck?

Definitely your stall, you need about a 2800-3k stall. tune could be off to but a looser stall will help you immensely.

 

[absintheisfun]

Re: Bigger turbo, slower truck?

Definitely your stall, you need about a 2800-3k stall. tune could be off to but a looser stall will help you immensely.

forgive my ignorance, but doesn't the stall just help spool times? It spools as fast as the stock turbo (according to memory)

 

[WyoSyclone]

Re: Bigger turbo, slower truck?

I too have the Stage1 and I feel some of the same frustration you're feeling. I've been working on the tune with it for over a year now via Code59 (taking time out for our LONG winters of course).

Mine drives great, smoother than my 02 Bravada: but, I just can't seem to make any power out with it. Mine spools great (I've got over 100 DM runs if anyone wants to see). I have to back the timing way down to keep out of KR.

My final test might be this weekend.. a racer buddy is going to give me a tankful of 116 and we're going to turn up the boost and the timing to see if we can make some horsepower.

I did manage to get the compressor map for the Stage1 and I have to say that I'm not all that happy about the map.. it doesn't get up into the 70% efficiency range until you get up around 20lbs of boost. The map is pretty narrow, and peaky.

In summary, I think it will turn out that this is an OK upgrade if you want to run high boost, high octane fuel (two gallons of xylene didn't help me all that much), or an alky kit (which I have, but haven't installed). The Stage1 is OK for driving around and cruising, but I'll reserve my final judgement for when I get the good fuel in it.

In fairness to Mike (I hope he posts here), I just got my FP gauge installed and need to verify proper rising rate FP... but I really think I'm fine there. I wish I could get Dig out here for a weekend... he's got a lot of experience that I'm sure would shed proper light on the subject


EDIT... I would think that you need larger injectors. I'm running KB 40lb'ers on mine at 48lbs static FP (engine off). My guess is that stock injectors would be maxed out.
Also, I have to say that my observations are via my butt dyno.... and it's older and slower these days I got Dynostorm for my Blackberry... I'll be digging it out this weekend too. HTH

 

[WyoSyclone]

Re: Bigger turbo, slower truck?

Here's the compressor map for the Stage1.. in my previous post I referred to it as 'peaky'... that may not have been the correct word.... but it does have to move a lot of air (high boost) to get up into its high efficiency area... running lower adds approximately 50 degrees of heat to the intake charge....

 

[qbnkiller]

Re: Bigger turbo, slower truck?

To those of you with an RPM stage 1 turbo...PM me and I might be able to help you get more out of it.

 

[turbodig]

Re: Bigger turbo, slower truck?

Here's the compressor map for the Stage1.. in my previous post I referred to it as 'peaky'... that may not have been the correct word.... but it does have to move a lot of air (high boost) to get up into its high efficiency area... running lower adds approximately 50 degrees of heat to the intake charge....

Actually, you gotta remember you're at higher altitude... your pressure ratio *is* higher.

Personally, I don't think there's enough exhaust housing on these things, but that's just my .02.

It'll be interesting to see how she runs on 116. You should be able to run at least 20 degrees of timing and 20+ psi on the good stuff.

You should bring her around to Car Craft this summer...

 

[WyoSyclone]

Re: Bigger turbo, slower truck?

Actually, you gotta remember you're at higher altitude... your pressure ratio *is* higher.

Personally, I don't think there's enough exhaust housing on these things, but that's just my .02.

It'll be interesting to see how she runs on 116. You should be able to run at least 20 degrees of timing and 20+ psi on the good stuff.

You should bring her around to Car Craft this summer...

Hey Dig... glad you saw this. I'm anxious to see what the 116 will do. One of the guys I'm sponsoring with ZDDPlus wants to run at Brainerd... I should load the Sy in the trailer and bring it too!

 

[BoostedSUV]

Re: Bigger turbo, slower truck?

Doesn't make sense why it would spool great, hold 15 psi and not make any power? Has to be something with fuel/timing map. A higher stall would get it rolling and spooling faster but that doesn't explain it feeling slow. Where is the wideband at at WOT, how much WOT timing are you guys running?

 

[Whiplash]

Re: Bigger turbo, slower truck?

Doesn't make sense why it would spool great, hold 15 psi and not make any power? Has to be something with fuel/timing map. A higher stall would get it rolling and spooling faster but that doesn't explain it feeling slow. Where is the wideband at at WOT, how much WOT timing are you guys running?

I agree. Could be too much fuel. Had this problem on my turbo'd Sierra. The first tune was way off, and this particular guy was supposed to be good as well. Next tune by someone else gave me damn near 125HP more!!! My truck kept pulling timing thus killing power until the better tune as well. Good luck with your truck!

 

[Osmosis]

Re: Bigger turbo, slower truck?

I agree. Could be too much fuel. Had this problem on my turbo'd Sierra. The first tune was way off, and this particular guy was supposed to be good as well. Next tune by someone else gave me damn near 125HP more!!! My truck kept pulling timing thus killing power until the better tune as well. Good luck with your truck!

I wonder what your Air/fuel ratios were before and after your tune to get a difference in HP near 125hp from one tune to the other?

Doesn't make sense why it would spool great, hold 15 psi and not make any power? I wonder if you have done a leak down test? Just a thought as boost psi could be passing the rings or the valves??? Just a thought.

 

[gkrcr882]

Re: Bigger turbo, slower truck?

From what I gather, you aren't feeling the "kick" that you used to feel with the old turbo. is the exhaust housing larger than the stocker? Basic turbo operation states that the smaller the exhaust housing, the faster the turbocharger spools up and hit peak boost. If you have something preventing that from happening (stuck open W/G or poor tune) you wont be at full boost as quickly as you were before. Heat, speed, volume and gas expansion are what spin that turbine, and if something is off you're reducing the force on it. If it put you back in the seat during a launch but fell off, its possibly because you had good boost pressure on takeoff, but the engine simply ran out of breath to spin the compressor until it was higher in the RPM range.

 

[Flyin Ryan]

Re: Bigger turbo, slower truck?

I don't know i've had a stage 1 for two years now and never had a problem with it other then fitment. Mine is set for 20lbs with meth though but you def don't need a higher then stock stall to spool it or else you have something wrong in the tune/wastegate adjustment.

In the original poster's case I'd suspect the tune.. most likely pulling timing due to the amateur tune job on it plus the ton of fuel it's seeing from the alky.

 

[qbnkiller]

Re: Bigger turbo, slower truck?

Without knowing the exact combination of parts used to construct the turbo, its difficult to point any fingers at the turbo being a problem. I can tell you that it sounds like there may be other issues that need to be addressed (timing/tune, exhaust backpressure, wastegate adjustment etc).

David at Bullseye Power (the manufacturer of the exhaust housing for that turbo) has offered to look at the turbos for just about free - you pay freight both ways, and he will not charge shop time to look at it. This would be to verify there isn't anything wrong with the turbo itself. The exhaust housing is capable of accepting quite a few options, so it is something you can build off of if you wanted to - talk to him about that.

If any of you want to take advantage of this, please call David Hall at Bullseye Power (231) 788-5209 and set it up.