Engine/Transmission (1994 - 1998) Easy way to reduce Lag?

[pwerwagn]

I was just curious about this. A bunch of guys I know run turbo'd cars (miata, saab, dodge stealth, etc). One of the guys saab was actually national champ last year in some saab rally of america. He has some sort of data acquisition wherein the computer records and plays back rpm, boost peaks etc. He was telling me the virtues of wrapping the exhaust manifold/turbo/downpipe with stuff such as thermotech, and also coating stuff with HPC. He saw a 1. 4 second reduction in lag (recorded from the computer, 2. 1 seconds before, 0. 71 seconds after the wrap). They run Water cooled turbos. Would this be a bad Idea to wrap my HX-35 and the intake manifold? I Know the stock man is already prone to crack, and this would probably make it worse. Has anyone done this? how about turbo-cool down time, would it increase drastically? My friend with the miata also saw a 2psi increase (32psi total) by wrapping/coating his T-3/manifold.

Just wondering if this is a feasible possibility for us.

 

[guava]

this is an apples and oranges type question

I'm by no means a dodge expert but I've enjoyed blowing up a rice burner on more than one occasion. My favorites is hondas.



My OPINION is:



Ricer is power curve is at 3000+ RPM. My honda works up to 10000 RPM.

Air flow is like 1/10th or maybe as high as 1/20 of what the dodge needs.

Temps are going to be much different (opinion).

The water cooling you mention is the same as 'intercooling' that cummins is using.



If I've read correctly, the easiest way to reduce turbo lag in the 12V engine is to get a smaller turbo housing. It will spool faster. The data they give on lag times seems a little long to me but thats a driving style too.



Hope this helps. Some of the real pros should chime in soon.

 

[pwerwagn]

the data he gave me was for a saab motor (i think like 1. 8L) that was making 38psi. that is why the lag was long. the water cooling on his is not only for intercooling purposes (in any at all), it also keeps the turbo cool. I agree with the fact that the airflow is different, as the miata is shifted at 8,500. the saab on the other hand makes peak torque at 2500 and peak hp at 5500, so it is slightly more relevant.

 

[guava]

I see your point. I'll admit to knowing absolutely nothing about saabs. I've got a friend I'll email your question to. He loves saabs.



What is the purpose of the 'wrapping' your talking about. Does it keep the heat inside the turbo or keep the turbo isolated from the engine compartment heat?

 

[pwerwagn]

The way I take it, it keeps the heat in and allows more of the heat energy to produce more boost and less lag. I guess less of the energy is lost into the atmosphere. Oh, and after reading my post i didnt clarify, the seconds lag he mentioned is from 0 psi to peak boost.

 

[KennyM]

Insulate the exhaust housing and manifold you will retain the heat to help spool the turbo faster. Heat is what drives the turbo. This would apply for any turbo powered car. I would recomend if your always in a hurry and can't wait to let your turbo cool down do not do it. It will require longer cool down, but the spool up will be much improved. Also it should cut down on underhood temp.

 

[Rattlin_Ram]

Talk to Y-knot he's done the wrap thing on his... .



Thread is here:

https://www.turbodieselregister.com/forums/showthread.php?t=107168

 

[chrleb1]

Many of the replies are pretty on. The turbo is just like a steam turbine. Take a river power plant, if you pass water through the turbines it will produce engery. Now turn that water into steam and let it flow at a lot higher velocity. A lot of times, the hotter the fluid (air), the easier it is to flow. So if you were to retain an extra 50 - 100 degrees, you could infact spool faster. Reducing you housing size is not always the answer. Doing this can hurt your overall air flow. If you talk to people that are making 500 - 600 -700 hp, they will tell you that air flow is everything.

Water cooled turbos... . you can find these on natural gas cummins motors (diesel motor that have converted). The exhaust manifold has a water jacket build around it to prevent cracking. It will also probably help the life of the bearings and stuff. Cracking the manifold... . this usually happens when the manifold cools too fast. Rapping the manifold also can slow down the cooling time and lets the metal "settle". Just some quick notes.

 

[pwerwagn]

So maybe cracking the manifold isnt a concern afterall. Acccording to Y-Knot, the spool up time reduction is significant. He did notice a increase n EGT, i think he said 150* or so.