A turbo manifolds job is to direct exhaust gas from the engine to the turbo. That may sound simple but a lot can go wrong if your turbo manifold isn’t built properly.
Things to consider:
1. Material
2. Runner size
3. Runner length
4. Wastegate priority
These are all things we can figure out for you and teach you about as we build your turbo manifold. With these variables properly set up your turbo manifold can be tailored to exactly how you want your car to perform and at the same time be a long lasting solution.
How your turbo manifold is fabricated and welded has a huge effect on performance and an even greater effect on how long it lasts. The life of a turbo manifold is not an easy one. No material likes to be heated up close to its melting point and then cooled down to room temperature over and over again but with proper construction they can be built to withstand just about anything you can throw at them.
Not only does your turbo manifold need to be built correctly in order for it to last but it also needs to be designed in a way that fits and functions with the rest of your setup. Just as a turbo manifold can be damaged by heat a poorly designed manifold can damage other components if not carefully designed with proper clearances and heat shields
Let’s break down some of our previously stated points starting with materials.
We currently offer turbo manifolds in 304 and 321 stainless steel although special requests can be made for Inconel or TItanium (titanium not recommended).
304 Stainless steel is the minimum standard. It withstands higher temperatures than mild steel, keeps heat trapped in which increases performance and keeps engine bay temps down, and doesn’t rust unless severely overheated.
321 Stainless steel although a little more expensive handles extreme heat even better, and does an even better job of holding that heat inside the manifold.
Inconel is the top tier option. Inconel is a nickel alloy that is stronger and lighter than stainless steel and can handle incredibly high temperatures although it is more costly. Serious racers looking for every competitive edge may want to consider this option.
Titanium is a great material for weight savings but it doesn’t handle the extreme heat cycles of a turbo manifold well. It may be able to be built to handle the stress for a time but its not a good choice for a long term reliable solution in most cases.
Proper runner size is essential for getting your turbo to behave the way you want it to. We offer stainless steel runners in two common size.
1.25” sch 10: This is the smaller runner size but don’t let that fool you it is still capable of supporting up to 2,000 HP in many applications. The difference between 1.25” sch 10 and the larger 1.5” sch 10 is in turbo spool and power band.
The smaller runner takes less time to fill with exhaust gas and reach the turbo resulting in faster turbo spool. Sometimes as much as 1000 rpm sooner than 1.5” sch 10. The trade off is that it doesn’t perform as well at high rpms as the 1.5”.
1.5“ sch 10: This larger runner has the opposite characteristics as the 1.25” sch 10. It doesn’t perform as well down low but gives you the best high rpm and peak power capability.
Turbo spool depends on a long list of factors but as far as runner selection goes we often recommend a small runner for street cars and a large runner for drag cars or other large displacemet high HP vehicles.
How many times have you heard someone talk about equal length runners being incredibly important? Well with turbo manifolds thats not exactly the case. Not because they don’t help, but because other factors take priority in a turbo system.
Like we said in the “What does it do?” section, the job of the turbo manifold is to quickly and efficiently get the exhaust gas from the engine to the turbo. Here is why speed and runner length matter. The heat in the exhaust gas increases exhaust pressure and velocity, colder gas equals slower spool, so we want to get it there before it has time to cool for maximum spool. Exhaust velocity also slows down the farther the exhaust has to travel so shorter runners are better. Thats the problem with equal length runners on a turbo manifolds, achieving equal length runners often involves lengthening the shorter runners to match the length of the longest runner which adds bends, increases restriction, and slows exhaust velocity, working against the job of the turbo manifold to deliver exhaust gas quickly to the turbo.
That being said we make every attempt to make runners as close in length as possible but we don’t go out of our way to do that if it requires making any of the runners longer than they have to be. It’s just not a worthwhile tradeoff.
If you have an internally gated turbo you can skip this section but if you require an external wastegate mounted to your manifold this is very important information.
Your wastegate vents off excess exhaust pressure to regulate how much boost your turbo makes, if it isn’t set up properly you can have all kinds of issues like boost creep.
Your wastegate needs to be sized properly and placed in the correct location and orientation to vent the exhaust gas’s off efficiently. If your manifold is built properly the exhaust gas will want to flow towards the turbo. In order to convince the gas to stop flowing towards the turbo when the wastegate opens it must be big enough and provide a smooth transition that makes the path out of the wastegate have less resistance than it would if it were to continue into the turbo. If these conditions aren’t met you end up with boost creep, your wastegate opens to let the exhaust out and limit the amount of boost your turbo can make but instead it keeps flowing into the turbo and doesn’t redirect enough exhaust gas to limit boost. This can cause serious issues and be difficult to fix if not done right the first time.
Our manifolds are built with the highest quality materials and processes. We start with a 3/8” thick header flange that resists warping. We bolt it to a 2 inch thick aluminum block that keeps it flat while welding and also acts as our purge block to flow welding gas inside of the runners as we weld them. Purging is an essential step, if it is skipped the chances of cracking a weld increase dramatically and with stainless steel, welds that aren’t purged produce a black oxide on the inside of the part that can break off into your turbo causing catastrophic failure.
We spend hours meticulously fitting each runner to our manifold fixture that we build to match your engine bay. We ensure perfect fitment and clearances from heat sensitive parts in your engine bay and design a wastegate outlet that will make your system perform flawlessly. We can build manifolds for any engine and any turbo.
Our manifolds also feature flanges welded on both sides which increases strength and creates a smooth transition from the manifold flange to the inside of each runner.
Once your manifold is completely welded we machine the flange surface flat so it seals perfectly against your engine. And then we coat the manifold in Zyclear, an extremely tough ceramic clear coat that helps keep engine bay temps down and keeps your manifold looking beautiful.
All of our turbo manifolds come with a lifetime warranty!
We don’t expect you to make all of these decisions yourself. Reach out to us and we can work together to come up with the best turbo manifold solution for your build. Text or Call (570)-352-6623 or fill out the form at the bottom of our home page.