I'm in the early stages of an engine rebuild and would like to know how quick can I hope to be with the stock turbo? Figuring I do all the other standard things to go fast, can the stock turbo take me into the 11's and if so how far?
I once had a dream that I could get to the 11's with my stock turbo. I don't think it will happen. Some people have. I don't run slicks or race gas, so I will never get there...
I wanted to keep it so that I could brag about my "stock turbo times", but it just wasn't meant to be.
My advice would be to see how much you could sell your stock turbo for and see about a TA-49. That will be my plan.
My stocker works fine, but with 120,000 miles on it who would want it?
Anyone else? No offense, but I hope there's better news for me than what Shawn gave me!
I appreciate the reply Shawn. I don't want to brag about mine being stock. As my handle says, I'm Low Budget! I'll spend it where I must to successfully rebuild this beast, but if it takes
a turbo to go faster, it will have to wait. I just wanted to know what was possible.
Thanks, Jeff (lowbudget)
A stock turbo can go hi 12's with the stock injs.
modified pump and volt booster. This is really pushing it and the motor has to be properly tuned
race chip,race gas and hi boost if too much knock,
boom. You could go alky again you need a properly
tuned motor.
I'd say Frank is about right on target, but I have gone 12.20 @ 108 with a stock turbo, but everything does have to be perfect ie: weather, tuned motor etc.
What about (not to beat a dead horse) with my new 50# injectors, head work, 62mm throttle body, Hemco 62mm plenum, high volume in-tank pump,etc. Is there still no chance of getting to the 11's? Were these items necessary to even get to the low 12's or is the stock turbo just a weak link to quicker times? In other words, without the better turbo I can't utilize the potential of the other parts? Think maybe I'm answering my own questions now.lol Throw me a bone guys! Lie to me and tell me what I want to here!(Just kidding) Jeff
That's a definite yes. your car would be pretty fast if you replaced the stock turbo with a bigger one. my car was all stock except the injectors they were green stripes and the TE 44 turbo, it even had the stock pump. The car went 12.47 at 109. The stock pump thing was just being stupid I have replaced it since then with a red armstrong pump.
What is different with bigger turbos that allows the higher HP? Is the extra size to allow an increase in volume without over-pressurizing the system? Also, am I in danger of doing this simply by increasing the capacity of everything else without replacing the turbo, or am I safe as long as I don't run a chip with too high a pressure? What pressure can a stock turbo safely create? If I'm not already in trouble using this turbo, what chip and from whom should I purchase for Delphi 50lb/hr injectors? And...is anyone familiar with Summit Engine Rebuild Kits? I see they have one for us with forged pistons. The pistons are Speed Pro. I see their numbers all seem to start with TRW-***. Is Speed Pro a supplier of TRW or do they manufacture a piston that coincidentally uses TRW as the beginning of their numbers? Does anyone know a machine shop in the eastern PA area who have used these kits? That's all for now. Thanks!
First off, you asked too many questions to answer in the limits of the discussion board. I'm having to cut my response into three pieces. :-(
The fastest I have actually seen with a stock turbo was Cal Hartline many years ago. He ran 12.1x's. He had a lot of modifications but I don't remember all his build up at the time. I do remember riding in his car and thinking "Wow, this is a monster. I'll never get my car going this fast." My car runs 11's now and with some tuning and my new front mount intercooler, I'm looking for the 10's. My wifes' GN runs low to mid 12s and we're currently building up a 10s motor for her. I'll be bolting the GN1 heads on this weekend. These cars will take over your life. I think I remember seeing the stock turbo rated around 600 - 650 cfm which puts it in the 400 HP range. No, I don't know the source so this is rumor/hearsay.
>What is different with bigger turbos that allows
>the higher HP?
In short, they're bigger and have less resistance to the airflow.
>Is the extra size to allow an increase in volume
>without over-pressurizing the system?
No.
The wastegate controls the maximum pressure. The extra size is basically to reduce the back pressure and load on the engine for a given airflow. Larger turbos can compress more air with less RPM and proportional leakage around the turbine blades. This is reflected in their "efficiency" ratings at higher compression ratios and higher air flows. Basically, they heat the air up less when you push them. The down side is turbo lag. It takes more air to start a larger turbo spinning. This is why people change to higher stall torque converters. Porting the heads helps here too. Porting the heads is probably the biggest performance enhancement to do to our cars. There have been significant changes in the turbine blade technology since 1987 and some of the newer, slightly larger, turbos will spool up as fast as the stock turbo.
continued...
Craig Watson
>Also, am I in danger of doing this simply by
>increasing the capacity of everything else
>without replacing the turbo, or am I safe as
>long as I don't run a chip with too high a
>pressure?
No, well maybe. Yes, but maybe. Kind of a hard question to answer keeping it simple.
First, you have done the right thing by addressing the fuel first. Many people hurt their motors from lack of fuel. Over pressure isn't a real issue if you have enough of the right fuel (high octane). Most people running pump gas can't run more than 17-18 PSI due to octane limitations.
Running race gas and sticking with the stock turbo will eventually push your manifold temperatures to high. When they get much over 200 degrees F, you will start to have detonation (i.e. head gaskets) problems.
The chip only modifies a percentage of the maximum pressure the wastegate is set for. The stock ECM actually doesn't measure the manifold pressure.
>What pressure can a stock turbo safely create?
It depends on several things. Octane, your intercooler and the ambient temperature are the two primary issues. Most people agree that the stock turbo is pretty much "done" between 21-23 PSI. Some people can't get their stock turbo to produce 23 PSI. I think the turbo could, but they are watching their knock retard (KR) and back off before they hurt anything.
When you really get a turbo spooled up and moving a lot of air, it can create more volume than can be consumed by the motor and bypassed by the wastegate. Then you have an over pressure situation. This is called boost creep. It is common to port (grind and polish) the stock turbo's wastegate hole to the largest that the wastegate puck will cover. If you do this, you might want to port the exhaust outlet of the turbo too.
>If I'm not already in trouble using this turbo,
>what chip and from whom should I purchase for
>Delphi 50lb/hr injectors?
There are several people on the list who make good chips. I'd go with one of them where you get a chip tailored to your car rather than a chip with a catalog number like a few suppliers offer. Some of the suppliers also will make one customized for your car.
continued...
Craig Watson
>And...is anyone familiar with Summit Engine
>Rebuild Kits?
A lot of people are. I used one for my car. It is a good deal, especially for a budget. Now, I have opinions and choose different brands for some things. I like Clevite bearings. I don't really have any bad experience with the Federal Mogul bearings in the kit, but I buy Clevite's anyway.
>I see they have one for us with forged pistons.
>The pistons are Speed Pro. I see their numbers
>all seem to start with TRW-***. Is Speed Pro a
>supplier of TRW or do they manufacture a piston
>that coincidentally uses TRW as the beginning of
>their numbers?
Federal Mogul purchased TRWs automotive aftermarket business operations a while back and sells a lot of TRW stuff. They also own Fel-Pro and they have combined a lot of operations. The pistons are made by TRW but they're in the Federal Mogul Speed-Pro catalog under the Speed-Pro name.
The pistons are good forged pistons. The particular alloy and design they use is a little heavier than some of the higher performance brands (like J&E) but it allows control of the expansion due to temperature better. This means there is less piston noise and rattle when you start the engine cold than a lot of forged piston motors. They are still lighter than the stock cast piston. The kit provides a heavier wrist pin so you don't have to re-balance the engine. A go-fast thing to do is get some lighter Pontiac wrist pins and re-balance the motor. There have been a few people who had lubrication and galling problems with the wrist pins. There are details about this and how to drill a hole and provide more lubrication in the archives. I haven't had this problem.
>Does anyone know a machine shop in the eastern
>PA area who have used these kits? That's all for
>now. Thanks!
Sorry, I'm in Florida.
Later,
Craig Watson
Thanks Craig,
I new I was asking alot of questions. I appreciate the wealth of valuable information you took the time to give me. I appreciate all the help everyone gave me in this thread. I've been struggling with some physical problems and haven't worked in over a year. Money's obviously tight and this is a bad time to get into a rebuild, but sometimes these things happen. I'll get it put together as long as I get the continued support of good guys like all of you!
Thanks again,
Jeff Medlar (Low Budget)
PS Anybody on Eastern PA machine shops? I'd put this bottom end together myself, but I'm a little concerned I won't get the clearances right.
I've run 12.20's @110 with a stock turbo, intercooler,injector car with not a lot of mods on drag radials at a crappy track with less than perfect conditions. It's not all that hard. I'd rate it a 4 on the hardness+expense scale. Getting a mustang 5.0 to run 13.6's with the same mods would rate a 7 out of 10.
You'll need race gas and a good chip like a $25 Thrasher 108. Good back tires will help tremendously. I used 275/50 drag radials, but I feel 275/60's or 28" tall ET streets would work even better with a stock car. The stock combo doesn't like to rev, so a taller tire will help keep the RPMs down and use all the torque the motor makes.
A good K&N cone filter, a right side airbag at about 25 psi, a ported stock elbow and a dump, 114 or better race gas with the boost set at 20-22 psi should net a very low 12, with high 11's being theoretically possible (good track, good conditions).
Lots of little tricks are involved, though. You have to race a lot to learn all of them. Find someone running fast with few mods and pick there brain. It could save you thousands in the long run not buying a lot of parts you don't need.
http://perfauto.tripod.com
Chris hit the nail on the head! It matches my experiences as well ..
Also, check out the performance Recipes on the web page at:
http://www.gnttype.org/techarea/recipes/recipepage.html
I not only read them, I printed them and put them in the library next to my favorite "porcelan chair." I enjoy reading them and only wish there were more. Thanks guys.
Anybody in PA? Need a machine shop reference yet. Anyone ever get one done at HG Associates in Limerick, PA?
One other question. I see almost no references to Eastern Performance and as they are now called, ESP Products. What little I do see is not very positive. I have an ESP High Volume In-Tank fuel pump and was wondering if it was good for its rating of 50gph @ 50psi. This should get me into the 11's shouldn't it?
Good Morning jeff,
I don't want to continue on this subject on even message board. As I said to you before, we are not Eastern Performance, Inc. Please stop referring to us as such. This is the second time.
Re. H.G. They do good work. When we get backed up they do machine work for us. If they have any questions on how to assemble or clearance or parts to use they will also contact us. Price is average with everyone. Ask for Bob, tell him John @ ESP sent you.
Now you are getting on MY nerves. This thread is over a year old!! Any understanding we have come to can not go back and undo stuff written a year ago. At the rate you are going, people won't refer to you with any name soon. Chill out!