The spring bolts from down pipe to centre section….

[Grahamo spec c]

Finally got the new HKS system the other day.

Have the HKS cat down pipe (twin scroll) also.

instructions (diagram) on new system shows the cat down pipe to centre has spring type bolts.

Question is…… Can Similar bolts without springs be used?

cat down pipe has a donut to fit the centre section.

have other bolts that will fit with washer and spring washers, NCT soon so don’t want to have issues of blowing or that, when the zero/sports on it now passes the last 10 years.

long winded sorry!
Want ye folk say? I’ve only ever had several exhausts with flush fittings and metal gaskets!!

info or advice please thank you.

 

[BazGF8]

Normal bolts be fine , the idea of the factory spring bolts is to allow some movement on the donut without a blow

 

[Grahamo spec c]

Normal bolts be fine , the idea of the factory spring bolts is to allow some movement on the donut without a blow

Thanks Baz
Wasn’t sure if they came on the car many moons ago as I can’t remember.
Does the donut seal properly? All alien to me as said, I’m used to flat exhaust flanges with metal gaskets..

 

[davelegacy]

If the downpipe your using has the 2.5 flange with donut ring use the spring bolts. If its a 3" flat gasket flanges use normal bolt/nut