I have a 1990 Callaway Twin Turbo that I am considering putting a boost controller on.

I am having trouble controlling the boost and severe backfiring is occurring. The engine is "mildly" modified and I am running 15-17psi of boost on my chassis dyno.

The car is emissions legal with cat's and a full exhaust system. My best numbers so far are 609.1hp and 723.7tq at the rear wheels.

I would appreciate hearing from anyone with boost controller experience.

By the way, are there any other Callaway owners out there? I bought this car new in 1990 and it has only got 1770 miles on it!

 

542: Can I be your friend :chevy

 

How are your wastegates set up ? If you're backfiring you've got fuelling or ignition problems.

If you can't get boost control now with what you've got, a boost controller probably isn't the answer. The wastegates need to function properly before the boost controller is going to work.

 

I don't know anything about the Callaway setups, but if your wastegates are the two port design, with one vacuum/boost port on the side, underneath the diaphram, and then another port on top, over the diaphram, you have several options.

I just a used a manual boost controller on the dyno, but I have an electronic HKS controller that I am going to run in the car. The manual boost controller is just a manual air valve that limits the amount of boost/vacuum that can be applied to the top of the wastegate, acting against the diaphram increasing the amount of boost you can build past the wastegates spring rate. It's simple to use but doesn't give any variability except by turning the ****. The electronic controllers are nice because you can program them to limit boost at lower vehicle speeds, but allow you to make higher boost as vehicle speed increases and traction is regained.

Lack of boost control shouldn't be directly causing a backfire though, sounds like a timing or A/F problem, possibly caused by a vacuum leak?


[Modified by Monty, 2:36 PM 7/15/2002]

 

Ok, from now on I will make sure to check the "Save a copy of this post in MyNotepad" box. I had composed a somewhat lengthy response and hit "Post" and it just vanished. Oh, well here I go again.
**************************************** ******

Thanks for the feedback.

I am using the stock Callaway turbo configuration with a number of modifications. It is not the best configuration in terms of making power but it gets the job done. The turbos are the Rotomaster compact type with the wastegate exhaust path built into the turbo. The A/R is a very small .62.

The wastegates are bolt on with the two port design. I installed Turbonetics T04B H-3 Hi-Fi compressors with the Super H compressor wheel. I am also using the Turbonetics Norgren style boost controller that you twist the **** to increase/decrease the boost.

I use a Racepak data acquisition system to monitor the boost, vacuum, fuel pressure, and rpm. My DynoJet chassis dyno has a wide-band oxygen sensor with data-logging capability so I know what my air/fuel ratio is all the time - except when the engine backfires. The DynoJet rpm recording equipment doesn't like it when that happens and it stops for an instant.

My problem is definitly a lack of fuel to cover the increase in boost. When the boost initially hits at about 15psi it then drops back to 12psi. I then try to twist the **** but there is a fine line between 15psi and 22psi for my combination. I don't have enough fuel available for that much boost. I have a very hard time manually controlling the boost. That is why an automatic one of some type would be cool.

I know there are dual stage controllers out there that might address my problem, but I was wanting to see what people here were using. I have talked to a lot of salespeople about their product and it all sounds great at the time.

Monty: I have gone back through some of your posts and am impressed with not only your turbo motor but also your naturally aspirated one. It's awesome. I know from personal experience what it is like to have 723ft-lbs of torque at the rear wheels(appx.850ft-lbs at the flywheel). And you have a lot more than that. I purchased a set of 315 BFG Drag Radials and they were worn out in less than 40 miles of street driving. I never once wound it up from a dead stop and let it go. This is while driving from 35mph on up. On my chassis dyno, I have 4 straps in the rear to hold the car down. With them tightened up as much as possible, when the boost hits the tires actually spin and smoke violently. It is quite a sight. I have also fried two clutch setups including the Dual Friction Center Force. I have now ordered a McLeod Street Twin like I have in my '67. I hope this takes care of things. By the way, do you have a projected completion time? Do you plan on putting it on a chassis dyno? Bring it out here and we will give it a go. I made the same offer to Steve Kamis(Merlin522) and have not received a response yet. And he is a lot closer than you are.

69 N.O.X. RATT: I thought we were friends.

 

Post this over here as well. A bunch of the callaway owners hang out over here.
http://forums.corvetteforum.com/zeroforum?id=50




[Modified by bill mcdonald, 3:04 PM 7/15/2002]

 

Is the boost pressure line to the wastegate coming from the intake or the compressor ?

 

An electric boost controller will always work much better, but If you go that route, don't buy a cheap one. You would want one with a remote style solinoid, as the cheap electric ones are more prone to Spiking the boost.

If you want a cheap fix to fin tune your boost, check out the TURBO XS, manual boost controller, they have 3 kinds, a cheap one like the Turbonetics, then one step up is basically the same, but has an additional adjusting screw that allows you to fine tune your boost in 1/8 pound incriments practically. Then they have their dual stage setup where you can have a nice fine boost level, then flip an electric switch from the drivers seat and jump the boost up to what ever the hell you want. Best of all, this allows you to keep your lines nice and short making the chances of spiking much lower, and if it were to happen, the wastegate would react much sooner due to the short length of the lines as well.


So your in Puyallup? I am in Auburn, like a block from Pacific. I hope to take mine down to test and tune this Wed night, see what I can run now.


[Modified by WashingtonRacer, 8:15 AM 7/16/2002]

 

SloRvette: From the intake manifold. From their it splits and feeds each wastegate.

WashingtonRacer: Thanks for the info. I have actually looked at their website in the past at the dual stage and was wondering how it worked. Are you using this? I tried to look up some of your posts to find out about your car and I don't see anything. What do you have?

 

Do you have the diaphram regulator T'd off the boost reference to wastegate opening port ? Then the other line runs off the regulator to the wastegate close port ?

You might want to think about running the wastegate opening directly to the compressor housing. Then use the intake port to feed the the regulator.

Boost spike is usually the wastegate being just a little slow to react.

I gave up on the regulator setup a year ago. The regulator was just too sensitive. There was no way I'd turn the dial under boost. A bump or jar and all of a sudden there was 5 psi that I didn't want.

I've heard that 30 psi diaphram regulators are available at Graingers and aren't as sensitive.

I went with the Innovative closed loop controller.

 

SloRvette: Thanks alot for the info. It all makes sense. I think I am through with the diaphragm regulators.

I have never heard of this Innovative closed loop controller and could not find it on the web. Can you tell me how to contact them so I can investigate?

 

Well, I don't have any sort of Controllers on mine as of yet, and I will be going with a standard boost controller with a fine adjustment setting. (like that from Turbo XS) their dual stage I hear is very reliable and efficent, Though not that much less than a moderatly good electric style controller.

Anyways, about pics of my car. Someday I will have a site deticated to it. In the mean time I really just can't find much time to post pics or anything. I don't have much pushing for me to post any either. Mainly cause I do have high standards with my car, so I will not even show it in public till it's re painted, and new interior.

But for those who care to know, my corvette is a 1980. I purchased it on my 18th birthday (i'm 21 now) Anyways full ground effects kit, daytona 4 front end, with a twin turbo hood, 255x50 R15 in the front and 295X50 R15 in the rear, some nice no lip fender flares that have saved me numerous times from other asses opening their doors and hitting my car, and they look very clean to boot. umm... Slalom springs in front with a Composit fiberglass spring in the rear, ( I hope to go to the transverse front spring setup soon) And on to the engine. I will start by saying I have spent an excess of 7 grand plus, and put out 414hp to the wheels before even thinking of my twin turbo setup. It started as I just wanted to change the exhaust but then one thing led to another, and I found a twin turbo manifold setup on E-bay for 400 bucks. So I jumped on that. then I found 2 Rotomaster T04B turbos on E-bay as well, rebuilt them. then I tore down my engine, kept my forged flat top pistons, but o-ringed the heads and put a .93 thousands copper gasket in. (people said this would detionate all to hell, but it hasn't yet) I then went to a single plain intake, and a 950cfm carb, with the nytrophyl floats, had a custom inlet hat made, Picked up 2 blackstone intercoolers, 2 delta gates a TurboXs, type HRFL blow off valve, and then stuffed it all in the engine compartment. and it fits like a glove. It may not be the best looking compared to that of Monty's, But then again I am doing it all on a 14 dollar an hour job, and doing it all my self. On top of that, it only has cost me an estimated 5 ro 5.5 grand to accomplish. as of today I increased the boost via wastegate load setting, up to 10 pounds of pressure. I am still running absolutly no retard under boost, and a total of 38 degrees of advance, So I feel that my engine has alot of capability, which makes me so very happy, I have almost accomplished dream number 1.
I hope to get some boost controllers this weekend, since thats when I get paid again.

Anyways I plan on taking the risk and taking it down to next weeks street Legal drags to test it out. I would love to see the callaway setup. Do you ever go to any events or anything?

 

This should be the link for the controller http://www.innovativeturbo.com/Produ...tes/msbc-1.htm

If you decide to go this route, you can buy these through dealers for less than the retail price listed.




[Modified by SloRvette, 2:33 PM 7/17/2002]

 

WashingtonRacer,

What do you think about the TurboXS HRFL BOV? I was looking at it before I bought the HKS SSQV's and was wondering if it is really that much louder? I'm looking for something that I use to play with the RICER's with ;).

 

Monty: Did you read the post that I addressed to you? It is 4 or 5 above this one.

SloRvette: Thanks alot for the link. This may be what I am looking for. I will give them a call as soon as I have a chance.

WashingtonRacer: I am impressed with your project. Keep it up. And no, I don't go to any type of events at this time with the car because it is dismantled waiting for paint.

 

542C2,

Sorry I must have missed it.

I had similar problem with a Dual Friction clutch with my NA SBC 427. Even after giving it several hundred miles to seat and breakin as recommended by Centerforce, it would not hold and slipped noticeably as well. The flywheel was brand new, and it as well as the clutch surfaces were clean and grease/oil free, even when I took them apart.

I hope to have it back on the road aorund the first week of August. I only have another couple days work on it, but I'm heading out of town for 10 days later this week.

I'd like to put in on a chassis dyno at somepoint, maybe later this Fall, but I doubt it'd be realistic to take it out to Washington State to do so. Thanks for the offer though. If you're near Steve (merlin522) I hope he takes you up on the offer. I can't wait to hear what his car puts to the ground, it's going to be crazy!

 

Monty: I don't think that it is realistic for you to come out here either, but stranger things have happened.

Steve (merlin522) is actually very close to my location and was at my house once looking at my '69 Corvette with a drag race style tube frame. I still have not heard from him and I see that the last posting he made was an angry one dealing with norvalwilhelm. Maybe he has decided to stay away for a while, who knows.

I will be following your posts with interest.

 

The Blow off valve is actually pretty loud, but compared to the turbos when spooled, and the exhaust note, It fits right in. As far as playing with the ricers... I took my car down to an Import Drag race even at pacific Raceways tonight. "first time I took it out" Anyways It got many looks by the rice burners. but they became most intrested when I breifly popped the hood. Right after that I took off, and thats when I got everyones attention. And it was with the blow off valve. I had guys with skylines running across the pits to take a look. I didn't even put it to the floor. A new issue arose though. On the way home it stated to overheat, and very quickly, OH and I got a freaking rock chip on my windshield now. But honestly I have other things to worry about in the mean time.

Hopefuly I will have my issues taken care of in a swift basis, thats all I ask for.

 

I personally am going to be running The innovative setup as i am running there wastegates on my car. When i had the hks wastegates i was looking at the evc 4 because it was going to do everything i wanted and had alot of options ( i did not like the evc pro cause it just had too much wizbang stuff going on)
Lots of twin turbo cars in washington love to see this :smash:
Steven

 

Monty- Quick question. How close is that exhaust to your Master cylinder? it looks like is moved upwards. Is this so? I had one hell of a time with my master cylinder. I ended up throwing on a 87 booster "alot more slim" and an 87 master cylinder. Still didn't solve my clerance problems, so I ended up making a bracket that located the master cylinder about 8 inches forward of the booster. Looks pretty trick.