Alunox Stainless Steel Rear system development for Esprit Turbo HCi

[MarkKassim]

Alunox are looking for a rear system (turbo back) from a HCi Turbo to use to develop a Stainless Steel direct replacement.

 

I know this is rare car but if anyone has one and is willing to let Alunox have it for a while, they

Will give a discount on the new system. They will also pay the postage each way.

If you can help with this you can hold of me or email

leon@alunox.co.uk    Or    richard@alunox.co.uk

 Thanks

Mark

[CarBuff]

Alunox should be aware that the '88 and '86 - '87 were slightly different specs.

'88 had the EBPV (exhaust back pressure valve) fitted to the left joint of the muffler in the picture. Many owners have eliminated it (I know JAE Parts sells a spacer).

[MarkKassim]

Thanks , I have updated Loen and he has taken that into account. Sections will be connected using V Bands alowing for options.

[MrDangerUS]

Mark,

FYI,

Stevens exhaust and the G exhaust are not similar, regardless of it's being a UK, ROW or Federal car.

There were some clearance problems on US cars, start from page 33 here  https://www.lotustalk.com/threads/penelope-pitstop-resurrection.335777/page-33

 

 

 

 

 

[MarkKassim]

Hi Just an update, Alunox now have a genuine exhaust for the HCI Esprit and can now supply the full system for federal cars in 

the US and Europe.

 

I will give an update when the someone orders one and we can see the final result 

Mark k

[MarkKassim]

Hi another update from Alunox, they now have the full system designed for HCI federal Esprit As well as the other full systems for G and Stevens cars . Here are some shots of the new HCI full system which is a 3” Direct replacement for the original.

 

The is built to the usual Alunox standard , Mandrel bends, purge welded and V bands etc. I can get full specs if needed.  

Alunox can now offer the full systems for the G, HCI and Stevens Esprit and are open to a mixed Group Buy. Could you give me some idea if you would have an interest in this and what model your car is and if it would be a manifold , rear system or full system. This would give us some idea of the group buy quantities and so we can then work on the prices.

Thanks

Mark

[MrDangerUS]

Mark,

Alunox header installation combined with a higher flowing turbo, 3.25" CAI and Micklewright racing hi-flow exhaust (NOT muffler, but just straight resonator) morphed my S4s into a Rocket Ship!

Tubular header delivers absolutely incredible results!

However, in the past,  the HCI version was somewhat troublesome... US cars are configured differently. 

Remember Jenna's problems?  https://www.lotustalk.com/threads/1995-s4-turbo-exhaust-upgrade.464140/#post-5912462

I hope, that this time all the issues were carefully investigated and addressed.

More food for thought here:  https://www.lotustalk.com/threads/alunox-header-installation.469196/#post-6149952

[GavinT]

I’d be interested to know pricing - 88MY Stevens USA Spec (same chassis as 87 HCI)

[CarBuff]

On 20/12/2023 at 12:14, MrDangerUS said:

US cars are configured differently. 

Shape/specs differ, even among model years...

'86 - '87 HCI and '88 Bosch cars are different, for sure.

[MarkKassim]

Just an update , the Federal system is now on Group Buy under Site Sponsors

https://forums.thelotusforums.com/topic/122093-alunox-combined-product-group-buy-for-giugiaro-stevens-esprit-turbo/#comment-1041595

 

[MrDangerUS]

Mark,

Is it possible to get the system bolting directly to the turbo flange like in the picture?

The car is 1988 USA Federal, which still has 87 Giugiaro turbo position/location/geometry, but different body clearances.

I'd like to eliminate the OEM "adapter" which is a restrictive antiquity (junk!).

FYI, the OE muffler, CAT and EBPV valve weighs 45lbs.  Now, add to it wastegate & w/g extension!

It would be interesting to calculate the total savings, if someone had the weight of wastegate, w/g extension, OE cast iron header and turbo "adapter".

Thanks

John

[MrDangerUS]

FYI, OE components weights are:

Turbo adapter                                        1,900 kg

Wastegate bypass                                  2,381 kg

EBPV valve                                               0,451 kg

Wastegate                                                2,500 kg

Cast iron exhaust header                      12,700 kg

Pre-Cat downpipe                                    3,000 kg

Main CAT pipe w/CAT                                      ?

Muffler w/outlet pipe/tip                         15,000 kg

 

[MarkKassim]

Hi John , Yes I'm pretty sure that will be the case , Leon has done away with the adapter and put the O2 sensor in a similar position 

, but I will double check with him and I will get him to check your 59mm ID also while I'm there.

I will get back to you soon, and add you on the other thread when he gets back to me

Mark 

[MarkKassim]

Hi John, Yes it is the case the OEM "adapter" is now obsolete in this design and the 59mm ID can be accommodated.

Mark 

[MrDangerUS]

Great! Please add my name to the List.

Thank you

John

[MrDangerUS]

Alunox header, which eliminates the OE "turbo adapter”, offers a great opportunity to to open up free-flow of the exhaust gases and improve your car performance.

OE turbo turbine exducer diameter is small because of the restrictive "adapter" inner passage tube ID, (only 1,9"). Thus, the engine cannot breathe freely.

Whilst ordering a new header, one may consider revising turbo at the same time. Stock turbine cover (A/R .63) can be machined to accept a larger wheel. Stock compressor (A/R .48) cover can be ported to Super 60 trim. If you want a bit more power, with minimal lag, ask to port the turbine a bit bigger than stock using exducer diameter 2.1 to 2.2  (53 to 56mm).    Use a T3 compressor 60 trim.

T3 60 trim has a smaller flow capacity (34 lbs/min) Vs the Super 60 (36 lbs/min)

60 trim has a smaller inducer than the Super 60 Trim. You could consider the Super 60 with a ( stock) 0.48 A/R compressor housing to improve drive ability.

When increasing air flow, fueling has to be adjusted to achieve correct AFR. Also ignition has to be retarded little bit.

 

 

[snowrx]

Speaking of turbo upgrades, the manifold is also available with a T4 flange option.

[MrDangerUS]

Alunox prices are still very reasonable. Raging inflation makes this purchase a good investment, which will never depreciate. Keeping money on hand or in the Bank makes cash value loses pretty painful over the time.

Not too many realize that inflation is a Geometric Sequence (Series), which affects pricing in a horrific magnitude.  https://en.wikipedia.org/wiki/Geometric_series

For example, with an actual true annual inflation in USA of ~14%, the $1,000 item would cost $1,688 at the end of 4-th year. Yikes!
For real statistical data see: http://www.shadowstats.com/alternate_data/inflation-charts

[MrDangerUS]

Mark,

Would you please convey to Leon a couple of suggestions for further improvement of the CNC cut components of the system.

1. Add ~35 deg chamfer to the mounting holes to facilitate initial installation over the head studs. Runners can and will misbehave (rotate or droop), no matter how well you pre-position them.

2. The top nut pockets in the flanges need to be tad larger to be able to withdraw the ring spanner after final torquing.  Apparently, there are a couple of different stud length and gasket thicknesses. Original studs seem to be longer and come close to the relief pocket edge, often closing the stud-to-exhaust flange clearance.  Note, that 12mm hex nuts would not work with CNC cut flanges in this location. I had to use expensive K-nuts, which accept 10mm sockets and ring spanners.

.

If too long, the studs should be modified by grinding the tips little bit shorter.

Older header versions have ample room  for larger nuts.

CNC

CNC flange relief pocket,  top stud location only.

Shortened stud works much better.

[drdoom]

Do locking nuts on exhaust manifolds present a problem in that they clasp too firmly on the studs? I'd expect some unintended stud extractions might occur.

[MrDangerUS]

No, I did not experience any extraction incidents.

[MrDangerUS]

When parts will be manufactured, approximately?